Refinement of computer ATX power supplies, modernization, improvement, increase in reliability, reduction of noise and ripple. Laboratory power supply unit with protection from a conventional computer Computer power supply unit rework 12
Once upon a time, there were computers. They knew how to count quickly and a lot and even display two-dimensional graphics on the monitor screen. And everything on the computer screen was flat and dull. People wanted three-dimensionality, a sense of space, cinematic graphics. They modestly dreamed of a miracle. And a miracle appeared to the world in the person of 3Dfx Interactive.
Part 1 - Theoretical. And also an excursion into history
Founded in 1994 by four enthusiasts, the company 3Dfx Interactive introduces Voodoo Graphics to the world for the first time. Rather, not even a chip, but a chipset - PixelFX and TexelFX Engine with support for up to 4 MB of local memory, which at the time was akin to a miracle. And a miracle happened - 3D graphics have become a massive phenomenon for the personal computer.
In January 1998, 3Dfx introduced a new miracle in the form of the second generation of graphics chips - Voodoo2, along with the advent of SLI technology, which allowed multiple chips Voodoo2 work in parallel. SLI (Scan Line Interactive) [not to be confused with NVIDIA SLI = Scalable Link Interface], allowed several Voodoo2 cards to run in parallel, thereby increasing fps in games.
Games! For the sake of fairness, it should be said that among the revolutionary developments 3Dfx had at its disposal a unique API - Glide. The vast majority of games at that time were developed specifically for this API. Until now, many people remember TE games with great fondness. And many still play these classic games.
But that's not all. Subsequent developments of 3Dfx were no less significant.
For example, support for multi-chip solutions using SLI technology, but this time within the framework of one (!) Board for an AGP slot.
It's about the graphics chip VSA-100, which contained interesting features - multi-chip image processing, very high quality full-screen anti-aliasing and successful texture compression.
For the first time on one "consumer" video card, it has combined two (Voodoo5 5500) and even 4 (in the legendary Voodoo5 6000) graphics chips, namely 3Dfx. The latter, to the greatest regret, did not have time to get into the series. Since December 2000, 3DFX has ceased to exist independently, since was bought by NVIDIA.
Video card 3Dfx Voodoo5 6000 also known for being a harbinger of technology Quad SLI.
Four video chips on one printed circuit board. Since it was equipped with an AGP interface, and motherboards with two AGP ports did not exist, we can assume that the Voodoo5 6000 was the first graphics solution to combine four video chips in one system. Nvidia showed a similar product only! SIX! years later, with the release of Quad SLI-enabled drivers for combining a pair of dual-GPU GeForce 7950 GX2 video cards.
If we talk about multi-chip solutions, then we must mention the company Quantum3D ... And her technology Heavy metal on 3Dfx chips.
Before starting the description of Heavy Metal technology, it must be said that this technology belongs to the HI-END class (do not forget that we are talking about 1998-2000). So Heavy Metal isn't just a graphics station, it's more.
Heavy Metal is a high-performance graphics workstation to meet all the needs that the most advanced software (of the time) can have for users who don't care about the price of a product, they use the most advanced.
These users were: military training bases, NASA, some large graphic studios. They also used such things to train specialists in helicopter control and missile guidance, when it was necessary to recreate scenes of military action in real time with maximum realism. The system was also used by civilians at Ford Research Laboratories in Dearborn, Michigan.
Lockheed Martin Selects Open Architecture Imaging System AAlchemy by Quantum3D to improve the realism of the C-130 aircraft simulator.
Heavy Metal stations were designed for such tasks. In particular, the most powerful solution on VSA-100 3Dfx chips in history is AAlchemy modules.
AAlchemy graphics subsystems have a separate metal case, a cooling system consisting of two 150 CFM fans and other components. The AAlchemy deck fits into the Heavy Metal body. Moreover, the number of such decks can be up to four.
AAlchemy contains from 4 to 32 VSA-100 chips, for memory bandwidth from 12.8 to 102 gigabytes per second. AAlchemy uses this architecture to obtain 4x4, or 8x8 sub-sample, single-pass, full-scene, sub-pixel anti-aliasing with a FillRate of 200 Mpixels / sec. up to 1 Gpixels / sec. AAlchemy4 was only sold as part of Heavy Metal GX +.
Specification:
Supports 4 or 8 VSA-100 chips on one board.
Support for 1, 2, 4 channels in Heavy Metal GX +
Supports SwapLock and SyncLock precise synchronization.
Supports 16 bit Integer and 24 bit Z-buffer with 8 bit Stencil
Supports 32 bit and 22 bit rendering
Single, Double, Triple Buffering
Perspective correct bilinear, trilinear and selective anisotropic texture filtering support with per-pixel LOD MIP mapping with Gouraud modulated, detailed and projected texture mapping
Transparency and chroma-key support
Per-pixel and per-vertex atmospheric effects with simultaneous OpenGL compatible alpha blending
Supports 16, 24, 32-bit RGB / RGBA and 8-bit YIQ and color-indexed compressed textures
Support for texture compression FXT1 and S3TC
Support for textures up to 2048x2048
32 or 64 Mb Framebuffer
3dfx Glide API support, Microsoft Direct3D, OpenGL and Quantum SimGL
Memory bandwidth 12.8 - 102.4 Gb / sec.
66 MHz PCI 2.1 interface with multi-chip transfer capability
Built-in geometry pipeline with a capacity of 2,100,000 textured polygons per second.
135 MHz RAMDAC with Stereo support
T-Buffer technology support
Considering all of the above, it becomes clear why 3Dfx acquired a huge army of fans of its products. Over time, turned into fan-collectors. And just gamers who love and appreciate old, classic games.
Again, if in the 2000s many did not dare to dream of the Heavy Metal AAlchemy GX + graphics system, because it cost $ 15,000 even with one AAlchemy module, now all this equipment can be bought for more reasonable money. It is possible in parts.
How do you like it - to fulfill the dream of your childhood, youth, youth ... who how? Decorate your collection with such a beauty? The author of the article is one of the fan-collectors of 3Dfx and Quantum3D products.
When I got the chance to purchase a single graphics module from the Heavy Metal AAlchemy GX + system, I naturally did not miss it.
But collecting computer hardware differs from collecting, for example, stamps, in that the hardware also works. Having admired enough of the man-made miracle, it occurred to me that it would be very cool to run Quake on a video card with EIGHT graphic chips on board, plus everything removed from a military or aerospace simulator! I got down to business.
The video card has a PCI interface, which makes it compatible with any modern computer.
Let me remind you the nearest solution Voodoo5 6000:
has an AGP 2x interface, requires a motherboard for a chipset no older than 333, is not compatible with many motherboards (even if they support AGP 2x)
and is so rare that it appears only on e-bay no more than once a year at a price of 1000 euros. And it has a performance that is two times lower than that of AAlchemy. Of course, these are incomparable things, but still.
It would seem that it is easier. PCI slot card. This is practically in all computers ... But, as always, there is a "BUT". A dedicated power supply is needed to power this graphic monster. With these parameters:
Impressive? 2.9 V and 75 A !!! Almost a welding machine! The only comfort is that 75A is required for two AAlchemy video cards combined in SLI. For one, half is enough, and this is 30-35 A.
3.3 V and 30 A is still real. Available on many 400W power supplies. But where to get 2.9 V?
Buy a branded (native) power supply? You can of course try, but this thing is extremely rare. And it costs decent money. Even on such a worldwide market as E-Bay it is rare.
Many Western enthusiasts do it differently. There is an option using converters 12 V to 3.3 V DC / DC-Converter Artesyn SMT30E 12W3V3J
At first glance, simple and affordable. But the price of such a device is about 50 euros, and you need three of them. And getting them in Russia is not easy. And buying abroad ... is long, troublesome and expensive.
There is an option using a powerful laboratory power supply and powerful current relays
I tried to figure out how much such a power supply might cost. Found 20 A 5 V. The price is a little over twenty thousand rubles. How much will a seventy amp cost !?
I didn't like these options right away. In general, I saw such a solution: three power supplies - ordinary, computer ones. Connect the Pc-ON wires. Combine common (black) wires. And somehow modify one of the power supplies to get the desired 2.9 V from it. The first two positions were solved without problems. I had two power supplies:
1. Linkworld LPQ6-400W... This is a pretty dead block. But it will work fine for my retrocomp.
2. FCP ATX-400PNF A more modern block has a declared current of 28A along the 3.3 V line. Practically what you need.
But from what to get 2.9V? Basically, I have a single Quantum 3D AAlchemy 8164... Half of 75 will be enough for her. The power supply is designed for SLI of two Quantum 3D AAlchemy 8164. I only have one. According to the experience of foreign users, 30 amperes is enough.
And then I remembered about Powerman HPC-420-102DF... I have a schematic diagram very close to this block. And I decided to take it as a base.
click on the picture to enlarge
In power supplies made according to approximately the same scheme, 5 and 3.3 V is taken from one transformer winding. This means that such a unit has a power reserve along the 3.3 volt line. But there are two small problems. Overload protection and overvoltage and undervoltage protection. There is also such a thing called - "voltage imbalance due to uneven load along the lines." I have not considered how to deal with these troubles. Decided to "solve problems as they come." If the unit starts to turn off during operation, then I will bother.
I opened the block and refreshed my memory by downloading and reading the datasheet on SG6105... It is on this microcircuit that my power supply is made. The large, twenty-pin connector has three orange wires. These are 3.3V lines. One of them goes with the (usually) brown Vsens wire. Sometimes it is the same color, but thinner than the rest. This wire monitors the voltage change at the unit output along the 3.3 V line.
The wire goes to the power supply board.
And through the resistor R29 it comes to leg 12 of the SG6105 microcircuit. The leg is called VREF2. The value of this resistor determines the output voltage of the power supply on the 3.3V line.
According to the 18kOhm circuit. I found this resistor on the block board:
I unsoldered one leg of this resistor, thus disconnecting it. This can be seen in the photograph. I measured its real resistance with a multimeter. It turned out to be 4.75 kOhm. Whoa! Schemes and life are often different from each other!
Now I take a variable resistor with a worm gear with a resistance of 10 kOhm. These resistors are very popular with overclockers because allow you to smoothly change their resistance. Turning the resistor motor with a screwdriver, I set it to the required 4.75 kOhm. I control the value with a multimeter and solder it instead of R29 from the side of the printed tracks.
I do this for the possibility of adjustment. Then I make a hole in the block case to access this resistor.
Now we need to make the connecting wires of the block with the video card. AAlchemy has a special board with connectors. You can connect to it with the help of petals. But the design of my homemade case is such that the video card is upside down. Therefore, I will screw the wires directly to the card itself. Here:
I find orange wires in the bundle. I cut them out, clean them, carefully tin and solder two wires with a cross section of at least 2.5 mm square to them. I do the same with black wires.
(common, ground, minus power supply). I also take three wires so that the cross-section of the outgoing wires is equal to the cross-section of the incoming ones.
I assemble the block, insulate the soldering points of the wires with electrical tape. And the process of checking-adjustment begins.
For the load, I used a 20 W furniture spot. All assumptions turned out to be correct and everything worked correctly. 2.9 V was exposed without problems. If you repeat this moment, then note that I turned on the power supply without blowing a fan. It is possible for a short time. But it is better to run with a blower.
For a long time, I have had a homemade water-cooled case, the hero of the article.
It now contains the retroconfiguration:
- CPU Athlon 1700
- MB EP-8KTA3L +
- Mem 3 at 256mB
- GeForce GTS graphics cards
- QUANTUM3D AALCHEMY
I install all three power supplies on it.
I connect the blocks as follows.
I connect the green wires of the connector of all power supplies. Now all blocks will turn on at the same time. I connect any black wire of each power supply unit to each other.
This body is very spacious. Such a giant as Quantum 3D AAlchemy... If the first block is loaded - motherboard, processor, hard drive, GeForce GTS video card, then the rest of the load is only on the 3.3 volt line. In this case, there will be no voltage imbalance, because 3.3 V is stabilized separately from 5 V and 12 V. But the 5 V and 12 V lines cannot be left completely without load. Therefore, I hang neons and fans on them. Such beauty is obtained:
My Quantum 3D AAlchemy turned out to be an old revision and did not require a power supply of 2.9 V 2.7 V. I adjusted the required voltage with a variable resistor without any problems.
After checking everything again, I started the system. The monitor has so far been connected only to the GeForce GTS. After loading the operating system, I checked the supply voltages on AAlchemy. The 3.3V line was normal. But 2.7 V dropped to 2.65 V. I again adjusted to 2.7 V.
The operating system immediately saw the new device and requested a driver. I took the driver from here.
Here it is, the legend works. I connect a second monitor to the AAlchemy output. And I run the test.
AAlchemy works as a video accelerator in a regular computer. The 2D image is displayed by a regular video card, and the Glide applications are displayed by AAlchemy.
Part 2 - F.A.Q.
After a successful experiment to upgrade a conventional power supply and launch AAlchemy (hereinafter abbreviated "AA5") on a regular motherboard, I tried to assemble the native configuration of the graphics station Heavy Metal AAlchemy GX +:
- 2 Pentium III processors - 1000 MHz / 100/256
- 2 x processor motherboard Intel L440GX +
- Integrated Video CL-GD5480
- 1.5 Gb SDRAM ECC Sync. PC100R
The board has two types of PCI connectors 66 MHz and 33 MHz.
I drove AA5 on it. In the process, some of the subtleties of operation became clear. First I wanted to write a continuation of the article. But I realized that it would be more useful to present all the developments in the form F.A.Q... and place it at the end of the first article. Pros - all information is in one place and clearly presented.
This F.A.Q itself is presented to your attention:
1. Where can I get a manual for AA5?
2. What operating system should I use?
The graphics station was designed for use with Microsoft Windows NT4 and Windows 2000. But it works great with Windows XP too.
3. Where can I get a driver for AA5?
Huge selection of drivers for 3DFX is here
4. Where can you ask questions and discuss AA5?
Part 3 - Extreme. Practical tests
The third part, the most extreme. In the first two parts, it turned out that a single AA5 video card is not that difficult to run on a regular home computer. The price of the issue is an easy upgrade of a separate power supply. But .. Again "but". Now you can purchase a module immediately, consisting of two QUANTUM 3D AALCHEMY 8164 and nVSensor post-processor. 16 GPUs! But then it will take 75 Amperes to power two video cards! With non-standard 2.7-2.9 V.
For such currents, the above modification is not applicable. Firstly, part of the power goes to other lines 5 V, 12 V, -5V, -12V. The 5V line had to be loaded with a light bulb, otherwise voltage imbalance still occurred and the unit stopped working correctly. And this is additional power loss.
Overload protection also worked. In short, it was required to get honest 75 A from the power supply at a regulated and stabilized voltage of 2.7-2.9 V. Twice as much as the unit can give. But if the power supply unit is capable of delivering 400-480W on all lines, why can't you force it to give out all this power in one line? Can.
The original plan was as follows. Disconnect all protections and monitoring of all voltages. I solder all unnecessary details. And I make the unit work only for one line. And honestly to give out everything that he is capable of in ONE, this line with an adjustable voltage of 2.7-2.9 V. This spread is due to the fact that there are two versions of AA5. There is a 2.7 V supply, and there is also a 2.9 V.
I study in more detail the datasheet on SQ6105. And I'm developing ways to disable all protections. The principle is simple. We must deceive the SQ6105. There is a so-called "duty room" in the block. This is an independent 5V supply. It supplies power to the SQ6105 before turning on the entire power supply.
For example, how to turn off 5V monitoring? Apply a voltage of 5 V to the SQ6105 pin, which is responsible for this monitoring. And I will take it from this very "duty room". Monitoring +3.3 V? I'll take 5 V from the "duty room" and use a resistor divider to supply the required 3.3 V to the SQ6105! The only problem with 12 volts arises. But I also solved it. Anyway, I use three power supplies to power a computer with AA5 installed. I'll take +12 V from any of them.
What I did, I set out strictly point by point. I reworked the 480W codegen power supply. I have not upgraded it as soon as possible. Simple, no extra bells and whistles. And reliable. The only weak point is diode assemblies. But I changed them long ago. After previous alterations, it looked like this.
Has a scheme very close to this:
Scheme No. 1
Let's get started.
1. I connect the load to the output of the power supply - a 12 V light bulb. The PS-ON wire to the ground, which means - I short the green and black wires of the 20-pin connector with a paper clip. The light is on. The block is working.
2. I disconnect the power supply unit from the 220 V. (You need to pull out the power wire from the unit!) This is important. Otherwise, electric shock and possibly death. Electricity is a bad joke. I turn off the analysis of SQ6105 plus 5 V - I cut the track coming from pin 3, SQ6105 (V5 Voltage input + 5V, circuit 1), and I connect pin 3 by soldering to pin 20 of SQ6105 with a jumper or a 50-200 Ohm resistor (RR5 in diagram 1). Thus, I disconnect the SQ6105 from the power supply circuit and replace the monitoring of the output 5 volts with five volts of the "watchman". Now, even if the power supply does not supply 5V to the load, the SQ6105 considers that everything is normal and the protection does not work. Done.
I turn on the power supply unit for testing, the light should be on.
3. I disconnect the PSU from the 220 V. I turn off the definition of SQ6105 plus 3.3 V - I cut the track near pin 2 and solder two resistors, 3.3 kΩ from pin 2 to the case (RR7 in diagram 1), 1.5 kΩ from pin 2 to pin 20 (RR6 in the diagram). I turn on the power supply unit in the network, if it does not turn on, it is necessary to select the resistors more precisely in order to get +3.3 V at pin 2. You can use a 10 kΩ trimmer resistor. After each alteration, it is better to check the unit for operability. Then, in case of failure, the circle of error search will be narrowed.
4. I disconnect the PSU from the 220 V. I turn off the definition of SQ6105 minus -5 V and - 12 V - I solder R44 (near pin 6), and I connect pin 6 to the case through a 33 kΩ resistor, more precisely 32.1 kΩ (RR8 in diagram 1 ). I turn on the power supply unit in the network, if it does not turn on, I need to choose a resistor more accurately.
5. Disconnect the power supply from the network. I turn off the definition of 12 V. For this, I am looking for pin 7 of the SQ6105. This is a 12V input. If there is no 12V, the microcircuit turns off the power supply. I look at the board, from foot 7, the track goes to a resistor, usually with a nominal value of about 100 ohms. I solder the leg of this resistor - the farthest from the microcircuit. I solder a wire to the soldered leg, to which I will supply 12 V from another power supply. There is nowhere to take 12 V in this block, and this wire will perform the function of additional protection and guarantee the simultaneous operation of several blocks. The project requires the simultaneous inclusion of several power supplies.
6. I solder all diode assemblies. This is most conveniently done with a suction soldering iron. All assemblies are soldered together with the radiator on which they are installed. I unscrew all assemblies from the radiator and study them. I need to dial at least 80A, and be sure to have the same assemblies. Nothing came out of the soldered one. But in stocks there were two assemblies of 40A for 100 V. I install both of them on the radiator and connect them in parallel. Then I connect them with wires to the contact pads of the 5 volt line of the power supply. The wires should be as large as possible. From 4 mm 2 suitable for assemblies and 8 outgoing. Also, all involved tracks on the board, starting from the transformer, need to be powered up. Either solder the wires on top, or fill them with solder. Better both.
7. Now you need to switch the output of the error amplifier and the negative input of the SQ6105 comparator. To do this, we are looking for 16 (COMP) and 17 (IN) legs of this microcircuit. (This is, in fact, the very stabilization of the output voltage).
And starting from them I go along the printed paths and compare the real block diagram with the one I have. I reach the resistor that connects the 16 and 17 legs with 12V and solder it (R41 in diagram 2).
Scheme No. 2
I find a resistor that connects the microcircuit to 5 volts (R40 in diagram # 2). I solder it. Then I measure its value and solder in its place a variable resistor of a slightly larger value. Naturally, having previously exposed it to the same resistance. I solder, of course, not the resistor itself, but the wires going to the resistor. The resistor itself is brought out to the power supply case in a convenient place. I will use it to regulate the output voltage.
I unsolder all unnecessary parts (electrolytes on all lines except 5 V, magnetic amplifier chokes 3.3V, if the parts of the -5V and -12 V lines interfere) and the wires coming from the board instead of them I solder two wires with a cross section of 4 mm 2 to the 5 V output and general. (These are thick speaker wires in the photo). It is better to duplicate the output wires. The section of 4 mm is not enough. The wire may become hot.
8. I connect the load (12 V 20 W bulb) to the power supply output. I turn on the power supply unit to the network. PS ON to ground. The block should work. This means that I did not drop anything superfluous.
I measure the voltage on the bulb with a tester and adjust the voltage to the required value of 2.7 V or 2.9 V. There is very little work left.
9. Now it is necessary to remake the group stabilization choke for a higher current. The section of the choke core is quite sufficient. Insufficient wire size. Still, the estimated winding current is 40 A and will be up to 75 A!
I solder the choke and find a 5 V winding on it. These are two or three wires with a diameter of 1.5 mm. In my case, these are two wires.
The cross section of these two wires is 3.54 mm 2. Rated current 40 A. For a value of 80 A, double the cross section. I had a wire with a diameter of 1.77 mm. In order to dial the required 7.08 mm 2, three wires are required (do not confuse the cross-section with the diameter!)
I wind all the windings from the group stabilization throttle. I count the number of turns of a 5-volt winding. 10 turns. I wind a new winding on the torus of the magnetic circuit with three wires at the same time. To do this, it is convenient to immediately measure the required length of the wires, carefully fold them in a strip and twist the ends with two pliers. Then winding will be much easier. The turns of all three windings must be exactly the same.
In the process of winding, I decided to use two such chokes to better smooth out the ripple. For the second, I dropped the throttle from the killed power supply and rewound it too. In principle, this is not necessary. The original circuit uses two chokes. The second is just a few turns of wire wrapped around a post. The core is too small for 3 wires. So I decided to put two identical ones.
I soldered the first choke to the place of the group stabilization choke in the +5 V contact pads. After it I put an electrolytic capacitor 4700 uF at 25 V, then the second choke (it replaced the capacitors that had been freed from the desoldering of the capacitors (along the 5 V line I also evaporated them, I it seemed that they were of insufficient capacity). I soldered it to the pads of the next choke. There was a small, nondescript. I removed it, drilled holes and soldered a new one. And at the output of this I hung two electrolytes of 10,000 uF 25 V. The current doubled, so and the capacity of electrolytes should be increased. Here the more, the better. It is also good to shunt them with ceramic capacitors with a capacity of 1-10 μF. This is for better filtering at high frequency.
Electrolytes of this magnitude were not removed from the board, and I attached them to the power supply case and connected them with wires to the printed circuit board. The wires must be of a decent size. At least one millimeter square.
To improve cooling, I made a new cover for the power supply from perforated steel and attached a 120 mm fan to it. He connected it to the wires supplying 12 V from the second power supply.
To control the output voltage, I wanted to make a built-in voltmeter. The easiest way for me is to put the arrow head. I did not find a head with a nominal value of 4 V. Found some strange device. I don’t know what he measured. But all dial heads are microammeters. And it is easy to make a voltmeter of them by installing a damping resistance. So I did. In series, the head included a 33 kOhm variable. Collected: it turned out pretty well.
I connected two blocks (from the second I take 12 V for the operation of the first, otherwise the block will not start, see item 5). On the second, I connected a light bulb as a load. It is not recommended to turn on blocks without load. I laid everything out on my favorite stool and realized that there was nothing to load the new superblock with. I remember physics.
According to Ohm's law I \u003d U / R, hence R \u003d U / I
U - Voltage, V
R - Resistance, Ohm
At a current of 75A and a voltage of 2.7 V, the load resistance should be 0.036 ohms. Conventional multimeters cannot measure such resistance. Not calculated. Well, let's remember physics again.
R - Resistance, Ohm
ρ - Resistivity for copper is 0.0175
L - Length of the conductor in meters
q - Section, mm square
I have a twisted pair of wires. 24AWG. This caliber corresponds to a section of 0.205mm 2. There are eight such wires. Four wires - 0.82 mm 2. Eight - 1.64 mm 2.
Immediately at 70 A, I did not dare to turn it on. Let's start with 35 A.
We calculate:
i take 4 wires, the length is 3.6 meters.
So, half of the lived 3.6 meters, resistance 0.0771 Ohm, current 35A.
All eight cores, 3.6 meters, resistance 0.038 Ohm, current 71 A. In general, it should be 70 A. But when calculating, I rounded. Two loads come out at once.
I connect half the load first. I turn it on. The block is working. The tension dropped a little. But I adjusted it with a variable. While fiddling, the wire got hot: 95 watts of heat!
Now I connect all eight: the current has reached 70 A! I turn it on - everything works !!!
Only the tension subsided a little again. But that's not a problem - we have an adjustment.
Only the load gets very hot - I can't carry out long-term testing. After 15-20 seconds, the insulation becomes soft and begins to "float".
P.S. In my case, for some reason, the overcurrent protection in the load did not work (short-circuit protection). I don’t know the reason. But if this happens, then this protection can be adjusted. It is necessary to reduce the resistance R8. The lower the resistance, the more current the protection will operate.
The power supply is ready. And you could plug in the AA5 and enjoy. But ... As always. Purchase from E-Bay haven't arrived yet :(
This material is discussed in a special thread of ours.
Hello, now I will tell you about the conversion of the ATX power supply model codegen 300w 200xa into a laboratory power supply with voltage regulation from 0 to 24 Volts, and current limiting from 0.1 A to 5 Amperes. I will lay out the scheme that I got, can anyone improve or add something. The box itself looks like this, although the sticker may be blue or a different color.
Moreover, the boards of the 200xa and 300x models are almost identical. Under the board itself there is an inscription CG-13C, maybe CG-13A. Perhaps there are other models similar to this one, but with different inscriptions.
Soldering unnecessary parts
Initially, the diagram looked like this:
It is necessary to remove all unnecessary, wires of the atx connector, unsolder and rewind unnecessary windings on the group stabilization choke. Under the choke on the board, where it says +12 volts, we leave that winding, we wind the rest. Unsolder the braid from the board (main power transformer), do not bite it off. Remove the radiator along with the Schottky diodes, and after removing all unnecessary, it will look like this:
The final layout after rework will look like this:
In general, we solder all the wires, details.
Making a shunt
We make a shunt from which we will relieve stress. The meaning of the shunt is that the voltage drop across it tells the PWM how it is loaded by current - the power supply output. For example, the resistance of the shunt we got 0.05 (Ohm), if you measure the voltage on the shunt at the time of passage of 10 A, then the voltage on it will be:
U \u003d I * R \u003d 10 * 0.05 \u003d 0.5 (Volt)
I will not write about the manganin shunt, since I did not buy it and I do not have it, I used two tracks on the board itself, we close the tracks on the board as in the photo, to get the shunt. It is clear that it is better to use manganin, but even so it works more than normal.
We put the choke L2 (if any) after the shunt
In general, they need to be counted, but if anything, a program for calculating chokes was skipping somewhere on the forum.
We supply a common minus to PWM
It is possible not to apply if it is already ringing on the 7th leg of the PWM. It's just that on some boards on the 7th pin there was no general minus after the parts were soldered (I don't know why, I could be mistaken that there was no :)
We solder a wire to the 16th PWM pin
We solder to the 16th PWM pin - a wire, and this wire is fed to the 1 and 5 legs of the LM358
Between 1 PWM leg and the plus output, solder a resistor
This resistor will limit the voltage supplied by the PSU. This resistor and R60 forms a voltage divider that will divide the output voltage and supply it to 1 leg.
The inputs of the op-amp (PWM) on the 1st and 2nd legs are used for the task of the output voltage.
The task on the output voltage of the PSU comes to the 2nd leg, since 5 volts (vref) can come to the second leg, then the reverse voltage should come to the 1st leg also no more than 5 volts. For this, we need a voltage divider of 2 resistors, R60 and the one that we install from the output of the power supply unit to 1 leg.
How it works: let's say a variable resistor is put on the second leg of the PWM 2.5 Volts, then the PWM will give out such pulses (increase the output voltage from the power supply output) until 2.5 (volts) comes to 1 leg of the op-amp. Suppose if this resistor is not present, the power supply will reach the maximum voltage, because there is no feedback from the PSU output. The resistor value is 18.5 kOhm.
We install capacitors and a load resistor on the output of the PSU
The terminating resistor can be supplied from 470 to 600 ohm 2 watts. Capacitors of 500 microfarads for a voltage of 35 volts. I did not have capacitors with the required voltage, I put 2 in series of 16 volts 1000 microfarads. We solder capacitors between 15-3 and 2-3 PWM legs.
Soldering the diode assembly
We put the diode assembly on the one that was 16C20C or 12C20C, this diode assembly is designed for 16 amperes (12 amperes, respectively), and 200 volts of reverse peak voltage. Diode assembly 20C40 will not work for us - do not think to install it - it will burn out (checked :)).
If you have any other diode assemblies, see that the reverse peak voltage is at least 100 V and for the current, which is higher. Conventional diodes will not work - they will burn out, these are ultra-fast diodes, just for a switching power supply.
We put a jumper for the PWM power supply
Since we removed the piece of the circuit that was responsible for supplying power to the PSON PWM, we need to power the PWM from the 18 V power supply on duty. Actually, we install a jumper instead of the Q6 transistor.
We solder the output of the power supply +
Then we cut the common minus that goes to the body. We do it so that the general minus does not touch the case, otherwise, short-circuiting the plus, with the PSU case, everything will burn out.
We solder the wires, common minus and +5 Volts, power supply duty room output
We will use this voltage to power the volt-ammeter.
We solder wires, common minus and +18 volts to the fan
We will use this wire through a 58 Ohm resistor to power the fan. Moreover, the fan must be turned so that it blows on the radiator.
We solder the wire from the braid of the transformer to a common minus
We solder 2 wires from the shunt for the LM358 op-amp
We solder the wires, as well as resistors to them. These wires will go to the LM357 op-amp through 47 ohm resistors.
We solder the wire to the 4th leg of the PWM
With a positive +5 Volt voltage at this PWM input, there is a limitation of the regulation limit at the C1 and C2 outputs, in this case, with an increase at the DT input, there is an increase in the duty cycle at C1 and C2 (you need to look at how the output transistors are connected). In a word - stopping the power supply output. This 4th PWM input (we supply +5 V there) will be used to stop the PSU output in the event of a short circuit (above 4.5 A) at the output.
Assembling the current amplification and short circuit protection circuit
Note: this is not a complete version - see the forum for details, including photos of the rework process.
Discuss the article LABORATORY PSU WITH PROTECTION FROM A CONVENTIONAL COMPUTER
Progress does not stand still. Computer performance is skyrocketing. And as productivity increases, so does energy consumption. Previously, almost no attention was paid to the power supply, but now, after the announcement of nVidia about the recommended power supply for its top-end solutions of 480 W, everything has changed a bit. And the processors consume more and more, and if all this should be properly overclocked ...
I have long resigned myself to the annual upgrade of the processor, motherboard, memory, video, as inevitable. But for some reason, the upgrade of the power supply makes me nervous. If the iron progresses dramatically, then there are practically no such fundamental changes in the power supply circuitry. Well, the trance is bigger, the wires on the chokes are thicker, the diode assemblies are more powerful, the capacitors ... Can't you buy a more powerful power supply, so to speak, for growth, and live at least a couple of years in peace. Without thinking about such a relatively simple thing as high-quality power supply.
It might seem as simple as buying the highest wattage PSU you can find and enjoying a relaxed life. But it was not there. For some reason, all employees of computer companies are sure that a 250-watt power supply will be enough for you in excess. And, what infuriates most of all, they begin to teach categorically and groundlessly prove their case. Then you reasonably notice that you know what you want and are ready to pay for it and you need to quickly get what they ask for and earn a legitimate profit, and not anger a stranger with your senseless, unsubstantiated persuasions. But this is only the first obstacle. Move on.
Let's say you still found a powerful power supply, and here you see, for example, such an entry in the price list
- Power Man PRO HPC 420W - 59 ye
- Power Man PRO HPC 520W - 123 ue
With a difference of 100 watts, the price has doubled. And if you take it with a margin, then you need 650 or more. How much is it? And that is not all!
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The overwhelming majority of modern power supplies use the SG6105 microcircuit. And its switching circuit has one very unpleasant feature - it does not stabilize voltages of 5 and 12 volts, and the average value of these two voltages, obtained from a resistor divider, is fed to its input. And it stabilizes this average value. Due to this feature, such a phenomenon as "voltage imbalance" often occurs. Previously, we used the TL494, MB3759, KA7500 microcircuits. They have the same feature. I will quote from the article mr. Korobeinikov ."... Voltage imbalance occurs due to uneven load distribution on the +12 and +5 Volt buses. For example, the processor is powered from the + 5V bus, and a hard disk and CD drive are hanging on the +12 bus. The + 5V load is many times over. exceeds the load by + 12V. 5 volts fails. The microcircuit increases the duty cycle and + 5V rises, but +12 increases even more - there is less load. We get a typical voltage imbalance ... "
On many modern motherboards, the processor is powered by 12 volts, then the skew occurs on the contrary, 12 volts goes down, and 5 goes up.
And if the computer works normally in the nominal mode, then during overclocking the power consumed by the processor increases, the skew increases, the voltage decreases, the power supply protection against undervoltage is triggered and the computer turns off. If there is no shutdown, then still the undervoltage does not contribute to good acceleration.
So, for example, it was with me. I even wrote a note on this topic - "Overclocker Light" Then I had two power supplies in my system unit - Samsung 250 W, Power Master 350 W. And I naively believed that 600 watts was more than enough. Enough may be enough, but due to the skew, all these watts are useless. I unknowingly enhanced this effect by connecting the motherboard from the Power Master, and the screw, floppy drives, etc. from Samsung. That is, it turned out - from one power supply unit, mainly 5 volts is taken, from the other 12. And the other lines are "in the air", which intensified the "skew" effect.
Modification of power supplies CODEGEN and others, JNC-like ... Sasha Cherny / 04/27/2004 00:56
This article (first draft) was written for my own project, which is currently in a dying state and will be repurposed. Since I believe that the article will be useful to many people (I judge by numerous letters, including from the readers of your resource), I suggest you post the second edition of this creation.
Good and stable computer performance depends on many factors. Last but not least, it depends on a correct and reliable power supply. The average user is primarily concerned with the choice of a processor, motherboard, memory and other components for his computer. Little (if any) attention is paid to the power supply. As a result, the main criterion for choosing a power supply unit is its cost and the declared power indicated on the label. Indeed, when 300 W is written on the label, this is certainly good, and at the same time the price of a case with a PSU is $ 18 - $ 20 - generally great ... But not everything is so simple.
And a year or two and three years ago, the price of cases with a power supply unit did not change and was the same $ 20. And what has changed? That's right - the declared power. First 200W then 235 - 250 - 300W. Next year it will be 350 - 400 W ... Has there been a revolution in the power supply structure? Nothing like this. You are sold the same PSUs only with different labels. Moreover, often a 5-year-old power supply unit with a declared power of 200 watts produces more than a fresh 300 watt. What can you do - cheaper and more economical. If we get a case with a power supply for $ 20, then how much is its real cost, taking into account transportation from China and 2-3 intermediaries when selling? Probably $ 5-10. Can you imagine what parts Uncle Liao put in there for $ 5? And you THIS want to normally power a computer that costs $ 500 or more? What to do? Buying an expensive power supply for $ 60-80 is, of course, a good way out when you have money. But not the best (not everyone has money and not enough). For those who do not have extra money, but have straight arms, a bright head and a soldering iron - I propose a simple revision of Chinese power supplies in order to bring them to life.
If you look at the circuitry of branded and Chinese (no name) power supplies, you can see that they are very similar. The same standard switching circuit is used based on the KA7500 PWM chip or analogs on the TL494. And what is the difference between power supplies? The difference is in the parts used, their quality and quantity. Consider a typical branded power supply:
Picture 1
It can be seen that it is quite tightly packed, there are no free spaces and all the parts are unsoldered. All filters, chokes and capacitors are included.
Now let's look at a typical JNC PSU rated at 300 watts.
Figure 2
An incomparable example of Chinese engineering! There are no filters (instead of them there are "specially trained jumpers"), no capacitors, no chokes. In principle, everything works without them too - but how! The output voltage contains transistor switching noise, sudden voltage surges and significant voltage drop under various operating modes of the computer. What a stable job here ...
Due to the used cheap components, the operation of such a unit is very unreliable. The actually delivered safe power of such a power supply unit is 100-120 watts. With more power, it will simply burn out and drag half of the computer with it. How to refine the Chinese power supply unit to a normal state and how much power do we really need?
I would like to note that the prevailing opinion about the high power consumption of modern computers is a little wrong. A packed Pentium 4-based system unit consumes less than 200 watts, while those based on AMD ATHLON XP consume less than 150 watts. Thus, if we at least provide a real power supply unit of 200-250 watts, then there will be less one weak link in our computer.
The most critical details in a PSU are:
High voltage capacitors
High voltage transistors
High voltage rectifier diodes
High frequency power transformer
Low voltage diode rectifier assemblies
The Chinese brothers also manage to save here ... Instead of high-voltage capacitors 470mkf x 200 volts, they put 200mkf x 200 volts. These details affect the ability of the unit to withstand a short-term loss of mains voltage and the power of the supplied power supply voltage. They put small power transformers that get very hot at critical powers. And they also save on low-voltage rectifier assemblies, replacing them with two discrete diodes soldered together. The lack of filters and smoothing capacitors has already been mentioned above.
Let's try to fix it all. First of all, you need to open the PSU and estimate the size of the transformer. If it has dimensions of 3x3x3 cm or more, then it makes sense to modify the block. First, you need to replace large high-voltage capacitors and put at least 470 microfarads x 200 volts. It is necessary to put all chokes in the low-voltage part of the power supply unit. The chokes can be wound by yourself on a ferrite ring with a diameter of 1-1.5 cm with a copper wire with lacquered insulation with a cross section of 1-2 mm 10 turns. You can also take chokes from a faulty power supply unit (a dead power supply unit can be bought at any computer office for $ 1-2). Next, you need to unsolder the smoothing capacitors into the empty places of the low-voltage part. It is enough to put 3 capacitors 2200μF x 16 volts (Low ESR) in the + 3.3v, + 5v, + 12V circuits.
A typical form of low-voltage rectifier diodes in cheap units is as follows:
Figure 3
or worse, like this
Figure 4
The first diode assembly provides 10 amperes at 40 volts, the second 5 amperes max. In this case, the following data is written on the PSU cover:
Figure 5
Declared 20-30 amperes, but actually 10 or 5 amperes are issued !!! Moreover, there is a place for normal assemblies on the power supply board, which should be there:
Figure 6
The marking shows that this is 30 amperes at 40 volts - and this is a completely different matter! These assemblies must be on the + 12V and + 5V channel. The + 3.3v channel can be performed in two ways: either on the same assembly, or on a transistor. If there is an assembly, then we change it to normal, if it is a transistor, then we leave everything as it is.
So, we run to the store or to the market and buy there 2 or 3 (depending on the power supply unit) diode assemblies MOSPEC S30D40 (for the +12 volt channel S40D60 - the last digit D - voltage - the more, the calmer in the soul or F12C20C - 200 volts ) or similar in characteristics, 3 capacitors 2200 microfarads x 16 volts, 2 capacitors 470 microfarads x 200 volts. All these parts cost about $ 5-6.
After we changed everything, the power supply unit will look something like this:
Figure 7
Figure 8
Further refinement of the power supply unit comes down to the following ... As you know, in the power supply unit, the +5 volt and +12 volt channels are stabilized and controlled simultaneously. With +5 volts set, the actual voltage on channel +12 is 12.5 volts. If the computer has a strong load on channel +5 (AMD-based system), then the voltage drops to 4.8 volts, while the voltage on channel +12 becomes 13 volts. In the case of a system based on Pentium 4, the +12 volt channel is heavily loaded and everything happens the other way around. Due to the fact that the +5 volt channel in the PSU is made of much better quality, even a cheap unit will power an AMD-based system without any problems. While the power consumption of the Pentium 4 is much higher (especially at +12 volts) and a cheap power supply unit must be improved.
Overvoltage on the 12 volt channel is very harmful to hard drives. Basically, HDD heating occurs due to increased voltage (more than 12.6 volts). In order to reduce the voltage of 13 volts, it is enough to break the yellow wire supplying the HDD, to solder a powerful diode, for example, KD213. As a result, the voltage will decrease by 0.6 volts and will be 11.6 volts - 12.4 volts, which is quite safe for a hard drive.
As a result, we got a normal power supply unit capable of delivering at least 250 watts to the load (normal, not Chinese !!), which will also heat up much less.
Warning!!! Everything that you will do with your power supply unit - you do at your own peril and risk! If you do not have sufficient qualifications and cannot distinguish a soldering iron from a plug, then do not read what is written here, and even more so do not !!!
Comprehensive noise reduction for computers
How to deal with noise? To do this, we must have the correct case with a horizontal power supply unit (PSU). Such a case has large dimensions, but it removes excess heat to the outside much better, since the power supply unit is located above the processor. It makes sense to put on the processor a cooler with an 80x80 fan, for example, the Titan series. As a rule, a large fan, with the same performance as a small one, runs at lower speeds and produces less noise. The next step is to lower the temperature of the processor during idle or light load.
As you know, most of the time the computer processor is idle waiting for the response of the user or programs. At this time, the processor is simply wasting empty cycles and heats up. Coolers or soft-coolers are designed to combat this phenomenon. Recently, these programs even began to be built into the BIOS of the motherboard (for example, EPOX 8KRAI) and into the Windows XP operating system. One of the simplest and most effective programs is VCOOL. This program, when the AMD processor is running, performs the Bus disconnect procedure - disconnecting the processor bus when idle and reducing heat dissipation. Since a processor idle takes 90% of the time, the cooling will be very significant.
Here we come to the understanding that we don't need to rotate the cooler fan at full speed to cool the processor. How to lower the turnover? You can take a cooler with an external speed controller. Or you can use the fan speed control program - SPEEDFAN. This program is remarkable in that it allows you to adjust the fan speed depending on the processor heating by setting a temperature threshold. Thus, when the computer starts up, the fan rotates at full speed, and when working in Windows with documents and the Internet, the fan speed is automatically reduced to minimum.
The combination of the VCOOL and SPEEDFAN programs allows you to stop the cooler altogether when working in Word and the Internet, and the processor temperature does not rise above 55C! (Athlon XP 1600). But SPEEDFAN has one drawback - it doesn't work on all motherboards. In this case, you can lower the fan speed if you switch it to work from 12 volts to 7 or even 5 volts. Usually the cooler is attached to the motherboard using a three-pin connector. The black wire is ground, red is +12, yellow is the speed sensor. In order to transfer the cooler to a 7 volt power supply, you need to pull the black wire out of the connector and insert it into a free connector (red wire + 5 volts) coming from the power supply unit, and insert the red wire from the cooler into the power supply unit connector with a yellow wire (+12).
Figure 9
The yellow wire from the cooler can be left in the connector and inserted into the motherboard to monitor the fan speed. Thus, we get 7 volts on the cooler (the difference between +5 and +12 volts is 7 volts). To get 5 volts on the cooler, it is enough to connect only the red wire of the cooler to the red wire of the power supply unit, and leave the two remaining wires in the cooler connector.
Thus, we got a processor cooler with reduced rpm and low noise. With a significant reduction in noise, heat dissipation from the processor does not decrease or decreases slightly.
The next step is to reduce the heat generated by the hard drive. Since the main heating of the disk occurs due to the increased voltage on the +12 volt bus (in reality, it is always 12.6 - 13.2 volts here), everything is done very simply here. In the break of the yellow wire that feeds the hard drive, we solder a powerful diode of the KD213 type. A voltage drop of about 0.5 volts occurs across the diode, which has a beneficial effect on the temperature regime of the hard drive.
Or maybe go even further? Switch the PSU fan to 5 volts? It will not work just like that - the power supply needs to be revised. And it consists in the following. As you know, the main heating inside the PSU is experienced by the radiator of the low-voltage part (diode assemblies) - about 70-80 C. Moreover, the assembly + 5V and + 3.3V experiences the greatest heating. High-voltage transistors at the correct block (this part of the power supply unit is correct in almost 95% of power supply units, even in Chinese ones) heat up to 40-50 C and we will not touch them.
Obviously, one common heat sink for the three power rails is too small. And if, when the fan is running at high speeds, the radiator still cools normally, then when the speed decreases, overheating occurs. What to do? It would be wise to increase the size of the heatsink, or even split the power rails into different heatsinks. We will do the latter.
To separate from the main radiator, a + 3.3v channel was chosen, assembled on a transistor. Why not + 5v? At first, this was done, but voltage ripples were found (the influence of the wires that lengthened the leads of the + 5v diode assembly affected). Since the channel is + 3.3v. powered by + 5V, then there are no more ripples.
For the radiator, an aluminum plate with a size of 10x10 cm was chosen, to which a + 3.3v channel transistor was screwed. The transistor leads were lengthened with a thick wire 15 cm long. The plate itself was screwed through insulating bushings to the top cover of the PSU. It is important that the radiator plate does not come into contact with the power supply cover and the radiators of power diodes and transistors.
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
After such a revision, you can safely put the PSU fan at +5 volts.
Video card. A more precise approach is needed here. If you have a video card of the GeForce2 MX400 class, then in most cases it does not need a cooler at all (which, by the way, many manufacturers do - do not install a cooler at all). The same applies to video cards GeForce 4 MX440, Ati Radeon 9600 - there is enough passive radiator. In the case of other video cards, the approach can be similar to the above - switching the fan power supply to 7 volts.
Let's summarize. We have reviewed measures to reduce noise and heat generation in an AMD processor-based system. For example, I will give the following data. At the moment, this article is being written on a very powerful computer AMD Athlon XP 3200+, with 512 MB of RAM, a GeForce 4 mx440 video card, HDD WD 120 gb 7200, CD-RW and has a processor temperature of 38C, temperature inside the case 36C, temperature inside the power supply unit, measured with a digital thermometer on the radiators of power diodes - 52C, the hard drive is just cold. The maximum processor temperature during the simultaneous 3DMark test and cpuburn was 68C after 3 hours of operation. In this case, the PSU fan is connected to 5 volts, the processor fan with a TITAN cooler is connected to 5 volts all the time, the video card does not have a fan. In this mode, the computer works without any failures for 6 months, at a room temperature of 24C. Thus, a powerful computer has only two fans (operating at low speeds), stands under the table and is almost inaudible.
P.S. Perhaps in the summer (the room will be +28), you will need to install an additional case fan (with power supply + 5V, so to speak - for peace of mind ...), but maybe not, wait and see ...
Warning! If you do not have sufficient qualifications, and your soldering iron is similar in size to an ax, then do not read this article, and even more so do not follow the advice of its author.
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But even the best of these PSUs, unfortunately, are far from ideal “power supply engineering.” For example, the well-known problem of “noise” of a sound card when the power saving mode of modern processors is turned on. Or another problem - users accustomed to the old AT standard initially reacted negatively to the need to turn off the system unit and monitor separately. Many are accustomed to this need, some leave the monitor always on, and some turn off the computer using a general surge protector.
We will fight over the solution of these problems in this part of the article. It should be recalled that any intervention in the power supply is fraught with loss of warranty, and in especially severe cases, damage to equipment. So with any change, you must understand what you are doing and be completely confident in yourself.
Voltage waveforms with varying load have very noticeable ripple. This is exactly the signal you hear in your speakers. How can you get rid of it? Well, first, choose a power supply with the least ripple. Or modify what is available. For this, obviously, it is necessary to add additional filter tanks. The simplest and most convenient is to solder a large number of unpackaged capacitors to the back side of the power supply board.
They are very small in size with a sufficient nominal value (1mkF), their price is low and almost anyone can afford to buy several dozen such capacitors at a price close to the price of one or two bottles of beer. Don't be intimidated by the dimensions of the capacitors in the photo. They come in a little more.
Having soldered these capacitors between the tracks with all the output voltages and the ground of the power supply (if you look closely, everything becomes noticeable, not just the circled ones):
You can greatly reduce the noise heard at the output of the sound card. In addition, a significant decrease in the level of high-frequency components in the output voltage prolongs the life of the standard electrolyte capacitors of the power supply. And the stability of the computer will not be affected by this ...
When soldering capacitors into the power supply, it is necessary to ensure that there are no short circuits between the tracks along which the power goes and the common buses.
Now let's look at how you can modify the ATX power supply so that it can independently turn on and off the monitor when you turn on the computer.
Obviously, the most convenient option would be to install a relay of small dimensions, but sufficient switching power:
(there are a lot of these now sold in the nearest radio parts store) to control the voltage supply to the monitor. The control winding can be powered from +5 or + 12V, depending on the relay used. The connection diagram looks like this:
The diode is turned on so that the energy accumulated in the relay control coil, when the computer is turned off, glass on it to the ground. Choosing a diode is easy - any medium power silicon diode. For example, KD105 or 1N40007. A resistor and capacitor are needed to prevent sparking when connecting the monitor. The capacitor is selected with a nominal value of 0.05μF at 400V. Resistor - 1kOhm for 1W.
Here is the simplest diagram. It is highly advisable to include a pair of control relays that open both monitor network wires. This is necessary because if the electrical sockets where your computer is turned on have a neutral ground contact (i.e., connected to the zero of the power supply network), then it is possible that you will open exactly zero with a relay. And it, fed to the computer case (due to the same zeroing), will go along the ground lines of the signal wires and the power to the monitor will not be removed. Will your signal wires handle this current? I doubt it. So out of harm's way - put a couple of relays. At the very least, you can carry your computer and plug it into any outlet without worrying about grounding.
Unfortunately, most ATX power supplies usually lack a monitor connector (even an uncontrolled one). Therefore, you will have to pick up a drill, a hacksaw and a file in order to make the appropriate hole and place the connector that was at hand (or bought in a store) into it.
Here you can see the wire-cut grill on the back of the power supply. To improve the aesthetic perception, this hole can be covered with a wire mesh, which will be discussed in the second part of the article.
Now it remains only to connect the monitor to the received connector and enjoy its automatic on and off. However, in this case, a nuisance appears - in the case of replacing the old low-power PSU with a new one (and it does not interfere with modern glands at all), it becomes lazy to make holes in the new case. It's easier to replace the filling in the old case with the one taken from the new power supply. But there is already complete freedom for your wild imagination.