 So a lot of the stuff I've been doing recently has involved bench testing various pieces of electronics and Up till now I have been bodging together power supplies from old USB charges and things like that and this has never really been very satisfactory So what I'm going to do today is try to build a proper bench power supply out of this old ATX power supply These things are great. They're cheap. They're rock solid. They are more mostly indestructible They provide lots of current if you need them to and they provide rock-solid regulated Voltages, which is just what you need for electronics So what I'm going to do is Pretty straightforward. I'm just going to rip off the cables because I really don't need this spaghetti mass of PC power supply cables and Instead of replace them with the industry standard for bench power supplies Which are banana plugs So this is actually a pretty straightforward job. I have done this before and didn't manage to electrocute myself These things are straightforward to work on inside as There's plenty of space and it's big chunky tracks even on the low voltage side So I just going to take the lid off You Remove the big bundle of cables Then I will drill some holes in the case and just to install the banana plugs I Might be able to fit them in this hex mesh here, which would be nice But we'll see I'm not going to do that on camera because it will involve going out onto the Alkony and doing stuff with drills. I Probably shouldn't do it today anyway today is Sunday And you're not really supposed to make loud noises in Switzerland on Sundays loud noises meaning drills so The cables are connected with a cable tie which So they're they're anchored with a cable tie So that can come off Go into the bin I will just cut these off. I'm going to keep the wires. They'll come in useful for Bench-testing PC power supply components after I sold a banana plugs on to the end So these ATX power supplies will generate five volts 3.3 volts 12 volts minus 12 volts Some of them will generate minus 5 volts. I don't know about this one though And I don't know how many of these I'll actually bring out with Minus 12 and plus 12 that gives you 24 volts with minus 5 and Plus 12 that gives you 17 volts So you can actually get a reasonable range of voltages without needing an adjustable power supply It is important to be careful when working on them because these are mains devices and they've got big big big capacitors and And this one has been off for ages, so it's going to be completely discharged, but they can If you get a wire in the wrong place, then you'll have a bad day That's a lot of wires. They can supply huge current So the one thing you get from a real bench power supply. There we go Which you don't get from this is of course Current limiting. Okay, I'm not going to worry about that This might not be as easy as I thought actually a lot of this stuff is putted to the board And let's get the board out so we can have a proper look I've had to have left those wires longer so I could use them To connect up my banana plug. Oh great the Screws being putted suspect. They don't want people doing this Okay, I'm going to have to chip the Fresen off the screw if it's possible. Well the fan Just plugs on which is nice So I can just unplug that But this aside for space Screw. I don't know what they made this stuff out of Yeah, the warranty on this power supply probably isn't worth much at this point and Switch board is Not plugged it's screwed Can I get it off? I do not think I can to be honest It looks like the switches clip into the Clip in this way and then the board has been then soldered to the back of the switches So I cannot imagine how that would ever come off Given that the actual power supply wires here are pretty short That does not give a lot of space to work in But I can get at the bottom of the board, which is good enough. Yeah, and this is a Insulating plastic that's been glued into the bottom of the box This thing was seriously not designed for maintenance. Right. We've got some massive solder because it has to deal with monster currents and Everything is nicely labeled on the front of the board So now it's just a matter of removing These wires one by one and then soldering new ones in just adjust the soldering iron Set to four hundred four hundred three forty for doing some stuff with a multi-layer PCB Which was unsuccessful Melting fill the wire Seriously a lot of these and this will all be good ghastly Lead-free solder as well. Which is no fun to work with Okay That managed to heat the wire up. So it was too hot to touch but did not actually make it Did not actually remove it It's a bit more methodically So you've got a big bundle of These yellow wires Which connect to this monster solder block here. I am going to have to turn the soldering iron up again Nice intention place a heat it's possible These solder blobs are so sodding huge that the Soldering iron will be unable to Melt them. That would be a shame. So the other thing I could do of course is to just chop the wires off close to the PCB These yellow ones are plus 12 volts So I May not need that many of them Rather nice to get the whole thing off. I need to put some solder on in order to It's not your friend. Yes. Yeah, I think So I can see that it's actually melting the stuff I just put on and not melting the stuff on the board So there's a possibility that they're using high-temperature solder it's It's probably just that this is a big lump of solder and my iron is not producing quite enough heat for it We'll see. I said this was simple So one of those green wires I just removed well the green why there should be one We is actually the signal wire that causes the power supply to start up and I should have marked where it was on the board Well, never mind Once all the rest of the stuff has been cleared off the board, there'll be more space to work This enormous block here is all ground and that is going to be enormous fun to the solder More heat, but I don't think my line's up to this Luckily I have a blowtorch This is actually going to melt at all. I don't think it is So I do have a gas-powered soldering iron that produces loads of heat and I've run out of gas So that's not much use So I'm just going to try cranking this iron up some more. I don't really want to turn it too high It's on 318 right now, which is Very hot But that is actually beginning to melt this stuff So I should be able to gradually pick away at it But I don't want to get the board too hot because I might run the risk of damaging things So I'm just going to try to Move solder bit by bit. Oh, they're massive massive holes Through which yeah Look at that There were about four wires through that one single hole. So in fact, there's This lump is not solder. It's mostly it's mostly copper from the wires That explains why they're getting so hot and why they are so difficult to remove so in fact This now I have enough heat this should be straightforward enough Because they'll all come out as a unit. It's not too hot to touch. Yeah The wires are in fact crimped together and Then the entire metal plug is pushed through the hole and sold down That's just not right Okay, but anyway, it's coming Yes in hindsight a bar the better way to do this would be to chop the wires off further up and Not try to desolder them from the board at all Instead just use something like a chocolate block connector or solder them directly to the banana plugs Well, I assume that the reason why I'm doing this is so that I can make the mistakes that you don't have to Moving now loosen the join right that one's not coming out because It's actually crimped in place It's actually hooked into the board so that should now just neatly pop out Not so neatly pop out the other side Twels must come from here if we can do this at some boy That's the wrong wire rounds are going to be a big problem There's a lot of them a lot of these are being problems So these yellow ones are twelves and they connect. I think this pad here are the twelves So in fact, there's a big hole here Yeah, I can easily clear out with the soldering iron so So which one of these is this wire I'm jiggling means that this last bunch must be this one It's not 400 which is pretty hot it moved a bit but not much Let's try the other bundle of yellows Not enough I'm trying each bundle in turn and then as they get too hot to touch move on to the next one While it cools down. Yeah, some of these have been cut off too close to the board So I can't actually get a good grip on them I was not actually expecting this to be so difficult. I don't know if I can do something clever with the snips Just chewing through Actually working. This isn't just cutting solder. This is actually Chewing through the bottom of the wires and those big crimp connectors. We actually have holes open for 12 5 3.3 Etc. So I would like to get the rest out simply because this is a horrible mess But I think I may have enough to actually solder on the wires to the banana plugs Let's give this a few more goes anyway. Yep, that one worked Hey, that's all the twelves. So I do need at least some of the fives out to get some holes. Oh Right That's a five. That's a bundle of fives There's only one more bundle of fives by the look of it. So let's get this one to go Okay now We need some of the Ground leads. Let's see if I can identify a bundle with some long wires, right? This bundle goes to here It's not gonna work. I need the pair of needle nose pliers as I can never find Be right back. Found my needle nose pliers, which were of course with an easy arms length the whole time This gives me the ability to Nice intention without having to touch the hot copper wires. Yeah, I'm making no headway with that big lump of solder at all 400 is the maximum this the this soldering on will go to So it's not like I can turn this up any further One of the reasons I want to get the wires cleared off is so that I can see Board on the other side But I suspect That it's just ain't gonna work and I'm just going to have to Cut these off. Yeah, these wires are really hot See if I can get some more of this stuff off mechanically. Yeah, that caps pretty warm Wonder what it's rated at Can't see a temperature that does not feel good. I'm gonna have taken the track up one bundle of Earthwise the more I take off the easier it will be because there's less heat sinking the Less metal sinking the heat let's That work quite cleanly it hasn't touched the track at all. So let's try a bit more mechanical Leverage the thing that's happened might have happened here is that I've Bent the crimp so it now won't fit through the hole anymore It did move a bit. Well, I do actually have a couple of holes now for ground So possibly I don't actually need anymore. I would like to as I said shave off these wires so I can see the board and Most importantly see the labels on the board Getting access is going to be rather tricky If I want to shave them off at board level because it's all like buried deep between other components I would just remove some of these caps so I could get access because I can always put them back again later I mean that's a 10 volt Thousand microfiber capacitor. I think I've got several so even if I do break it I can replace it but It's all glued down with this yellow cuckoo spit stuff. So I think don't think that's a good idea Big lumps of copper wire Sucking away the heat I was going to expect soldering this thing could be the easiest part of the job Okay, so I'm gonna turn the soldiering on sign off while I think I'm not really happy about Because I kind of want to mechanically remove the As much as this metal as possible So what are my options other than soldering and trying to pull the crimps out? well There's always the pulling bits off with the the snips which is It pretty crude But vaguely successful small ones. You see all this stuff on my workbench. This is all soldered pulled off So it works. The other thing I suppose I could try is drilling out some of these plugs. That's rather more Mechanical and I was slightly rather hoping to do you see Incidentally all this Conductive debris I'm going to have to brush the board down carefully once I'm done Get as much of it off as possible You can actually see on the board The bits I'm working on on the left is the low-voltage stuff and the bits on the row the right The other side of this big dividing line is the high voltage stuff Which is nice? It means there's a decent separation between the two sides of the board You really don't want your high voltage mains to leak through to your low voltage DC Bad things happen. Ah got one So Next this That's not budging at all. Let me just double-check. I've got the right sort of wires. Yeah, looks about right Anyway, let's try this one instead This one comes from up here. So Let's try the snips again. He's now a dump so much heat into it the metal soft I am actually gouging up the PCB there. So let's stop doing that. I mean, it's not like there's plenty of track But yeah, the track is a nice ground pin there That's interesting. That's very interesting Yep, the soldering iron is too hot. I can tell because I've wrecked the tip Well, that's great It's actually corroded into a down one side. So let's crank this thing down to a rather saner 270 ish I'm gonna have to replace the tip. So I mean it's Now like buggered turn this thing off. I don't think I'm gonna have any more luck Trying to get stuff off the soldering iron. So can I in fact chop the wires off where they stand Don't think I quite have room I've got these terrible Top-facing snips, but they're really very bad and There's little not quite enough room The bottom of the board is actually quite cool. I'm gonna try to drill After all what could possibly go wrong? I mean, I'm working on a piece of delicate mains power equipment. That's that helped. I have a couple of holes through Plugs in the wires There's another bundle of wires that was removed through sheer brute force and ignorance however and I also damaged the PCB doing so I Mean it's fine. I'm Just to be on the safe side once it's done. I'll solder a jumper wire across these two bits of PCB But that was not the right way to do it. We now have three bundles of wires left hmm you know given that the The soldering iron tip is ruined anyway, I might as well turn the temperature back up Because it ain't going to get any more ruined and the other thing that might help is Snipping the wires off reduces the thermal mass and allows me to get the solder hotter So be more likely to actually get the stuff off. I'm not sure that I can snip them off Go on Fantastic, I think that leaves just one more bundle to go. Are all these the same bundle? They are And I thought there were two there. Okay? Good So this should actually yeah be so much easier Okay, right that's done Let's turn the soldering iron down to a much much say no temperature and let's see what we've got right now There are Multiple 12 volt supplies. There's one here and there's one here The five volt grid is here and there's a nice small hole for me to put my wire in Ground is here likewise a hole 3.3 is here now the Startup signal. Oh, yeah, this one here is plus five stand by so this is on even if the rest of the supplies off It is very limited as the current As a whole here mark ground, which is probably a ground Yeah, the one I need to positively identify is the Startup there's plenty of stuff on video so I might go back and figure out where it came from Yeah, look at this stuff nasty metal crimps and I managed to bash myself about There's a hole here with a diamond on it But that's just connected to the 3.3 volt lines. So that's not much interest Notice that the two big three point threes Here and the little one above it are not connected on the PCB. So let's just try Yep. Okay That's just me There's a hole down here Underneath all this grotty Hotting and I want to read the label. I think it says plus 12 So that's plus 12. Is it connected to the other 12? Interesting. I think it's connected by a capacitor Yeah It's also probably not our startup signal. There's a hole here this one Oh, that's I've seen that one that's mark ground. Yeah, I'm gonna have to go look at the video Okay, well that is progress even though it was really embarrassing progress So the plan has actually failed I I did drill the holes And it turns out that they are in fact slightly too close together To allow the banana plug sockets to go into place. There isn't quite as much space in the Uh in this opening than it appears there is Which is a problem because it means the banana plug sockets Won't fit so I still don't want to drill holes in this side because this will mean tethering the Top of the case to the To the wires So I think the only place I can put the banana plugs realistically is here And I don't want to put them here because as I said the main voltage stuff is all over there And I can't put them here because the fans in the way So I'm actually going to try some lateral thinking The fan fits in The top of the case I think it may be possible to remove the fan and mount it on the outside of the case With this grille still attached so that it doesn't chop people's fingers off Which would open up all the space along here To put sockets, so I'm actually going to give that A bit of a try just to see what happens I don't know whether the fan mount will actually Work at the top of the case, but the only way is to try it and see So this is another these are more phillips heads Versus posse drive If you pick the wrong one it almost but not quite works Those are weird. I can probably actually get away without the fan The amount of power this thing is going to be dissipating is essentially nil The piece the power supply is designed to run a 200 watt pc So this can fit there And the grille that actually is the little glued on that'd be great if it was Or is it just no it's not glued on it's just It's got these rubber mounts Those are some very old and manky rubber washers So if we can put it here with the rubber washers in place This wire has to go inside so Let it drop through like this This then needs bolting to the top of the fan Is that going to work? I think it might you know So let's reuse these rubber washers They have been holding this fan on for so long now it seems unfair to Throw them away Wherever the last one went there were four weren't there? I do not believe I dropped it See this is why I take video Yep tracked it down. I had in fact dropped it on the floor. Okay So I've been moving the thing around so much I've lost the orientation of Where everything goes the Box only goes on one way around So I need to be sure that it is in fact that way around because these Things here need to lock into place So it clips on like that the The power socket for the fan is there So this needs to plug in Like this if I can actually get it in and the fan needs to be this way up so it blows up into the air so the fan Mount the wires for the fan are on the South side of the box The label is on the north side of the box. Yes, that doesn't actually not go on the other way So with the with the label on the north side We turn it over We turn this over as well the wire is on the south side so It goes on like this Faith the rubber washers The fan as you can see is filthy I should actually clean it before I put this all together again So it goes on this way. That's not so bad Fan cover goes here And we need some nuts and bolts to fasten it on with What have I got here some? generic metal bolts You know the thing about all this dust is it's probably all me The computer this came out of I had for a while to probably do the others as well that's actually forced the Uh the hook at the end of the fan cover apart Isn't so hot and fan in place So that looks like it worked So I need the banana plug socket to go Here this will involve Taking apart some of the The hex ventilation drill So where would I put them here? The earth wire The grounding strap is somewhat in the way, but we can avoid that So they will go quite happily To apart So we laid out like this that allows me to put This one would go there, but I don't think That's too near the edge of the case. So let's go there That puts it In the middle of the grounding strap So if I go there get two for there get two for there So the tag on the end of the banana plug is not in the middle of the banana plug which makes it A little hard to keep track of where they are. Yep, that's quite reasonable This is a string a little into Main territory, but not too badly The good news is I probably don't even need to drill it Because I should just be able to If I'm strong enough I should just be able to Snip this thing apart Famous last words The other thing the hex drill might do for me is it makes it really easy to mount a power led Which is another thing I'd rather like. This is a bench power supply. I'm probably going to be turning it on and off a lot I need to know whether it's going to be on Before I start dismantling whatever it is. I'm dismantling. I'm currently running off it Okay, that wasn't what I wanted Everything is harder than it looks. What's a good way to get this apart? Probably not the drill and besides it's too late at night for that I in fact own two pairs of snips, which are These So I'm just going to have to try Try it with these and the the teeth The blades aren't quite narrow enough to go in the holes To go in the holes in the hex drill It does appear to be cutting. I have to be careful not to bend it actually Okay So elegant Can I leave me? This one is going to be 3.3 volts. So We actually want to arrange them in order of voltage So let's put ground this side and then we'll go 3.35 And 12 All right, that's not quite wide enough again I'm going to need to check carefully for metal fragments in the works because Shorting something out in your power supply is generally not considered a great idea Okay That goes in It's not brilliant It needs a washer, but I'm not sure I have any big washers It is amazing what you can do with the grommet so I need to Cut the grommet lengthways Try to cut the grommet lengthways This then becomes elastic enough to push up over the banana plug socket I then find the banana plug socket's bolt It's beautiful. Let's just try plugging it. Yeah, that's fine The rubber gives it a bit of flex which may cause it to come undone So I actually need to So I tightened it by rotating the Banana plug itself, but I actually need to tighten the bolt itself Because now the banana plug won't rotate because it's jammed by the rubber washer Yeah, and the washer's squashed flat good so It's much more solid excellent. I believe that's a success finally Okay so Skip one the next one I want to do is this one and looking at the washer Projects slightly into the The middle square so that there will actually be space once I snip out This one clean up. That's the next one Skip one This one is next This one will be the 3.3 volts The downside about this position is it's going to be really close to the mains plug here Which is that's not dangerous. It's just unwieldy. I hope that's true Because there are actually big chunks of exposed mains on the on that board there It should be okay. Okay Three holes one more to go. Let's get this one. It's gonna be this one. Okay Right So 3.3 volts, which is going to be green Go here, and I actually think I need a spanner for this One spanner There's absolutely no space to work I'm not sure the spanner will help Yeah, I get a bit of a turn How well plug it is that needs to be a bit tighter Yeah, that's actually pretty close. Also, my wire isn't long enough So I may need to take this board out and replace the wires with longer ones Yeah Always cut wires longer than you think Also, it is actually quite close to this big chunk of mains So I think I'm going to need to find a piece of cardboard or plastic or something Which I can tuck in there just to be on the safe side Anyway, that one's done So Cut up my other grommets Like so And score in my nice new cutting mat Well, that's what they're for And that did not actually cut straight in any shape or form Decence actually And the last one Is the 12 volt line In fact I managed to chop So much off the grommet Yeah, this the red one hasn't gone in straight because I didn't chop the grommet evenly She's going to take this one off again Have to saw another grommet in half of the yellow one Because that's uh, no good I don't think that was actually going round at all It looks like it was Oh The bolt has twisted and it's Okay, that's going to be interesting I need to unscrew this The bolt has in fact popped all the way through the The grid I think that was just bad luck Let's try this again Okay, yeah, if I can get the lug seated properly with the grommet Pushing through instead then that will make the bolt actually work Uh The nut rather Okay So now the poor yellow one Yeah, that's not right. I'm gonna have to Ruin another grommet. Let's see if I can do it right this time Perfect. Okay Yeah, that's okay. All right Fantastic So we have the black wire goes here The orange wire goes Here And assuming I soldered it on first time there's enough space The red wire goes here The yellow wire goes here. It's all a bit tight, but it should work God repulsive dust I'm actually going to try my patent wire stripper on this Which doesn't quite work right, but it's very good when it does work So, okay now tin the banana plug N tags Also trying not to draw to drip solder into the works. Okay. Now the orange one Which is the 3.3 volt line Is the tightest. So let's do that one first So that's going to go here No problem for five volts And Let's do here. Okay So the only other thing I really need Apart from the led which I'm actually going to do later is Some sort of shield for the mains going to have go poking around my various drug drawers Okay, so I've done some stuff offline I have I did actually add the led I said I was going to which is Rather crudely cemented into a hole in the hex grid It's connected via a 700 ohm resistor, which is about Three times bigger than I really need for this led, but I don't want it to be bright. It's just an indicator light and this piece of actual plastic is a just a precaution shield between the The mains voltage stuff down here and the low voltage stuff further up It's I mean there's plenty of clearance. There's a good centimeter or so, but Let's be careful. Anyway, so now the only thing to let do is to Put the lid on fire it up and hope that my house fuse doesn't blow So Label goes on the north side of the board So first I need to plug the fan in And the wires now make it a little less easy to reach the Socket, but that is what angled pliers are for Okay, and the screws go in the top, which is nice and convenient This screwdriver tip is not magnetic, which means holding the screws on is Not as easy as one would hope Okay The last screw Okay That now feels nice and robust and there's a good big hole here for sticking fingers in and there probably isn't much live in the other side But I will stick some tape over that once I'm done and on the now the front we have the four colored banana plug sockets for the low voltage a switch, which I'll set off And the mains input. Okay I'll hook it up and see what happens So it's hooked up to the mains Now press the switch I suppose and the spinny thing spins The LED glows Still quite bright actually And now I need some Banana plugs and we'll check the voltages So I've got some banana plugs with some crocodile clips. I've got the meter Now important safety tip These power supplies can generate a serious lot of current Why does that bother with the banana plugs? I can just stick this in the Yeah These supplies can generate a serious lot of current Which means if you short them out then Oh look at that 5.08 dead on that's nice and the green one 3.3 dead on and the yellow one Eh close enough That's great. It's not even particularly loud It's blowing air out of the power supply box, which means it's sucking air in through the grill on the front Yeah, uh, yes, if you short one out Then things can get warm the supply is supposed to like Fail without setting fire to anything But I've been hacking it about somewhat so don't do that Yes, well In conclusion This is how you incompetently turn a atx power supply into a bench power supply If you want to do this yourself Try to do a better job than I did In hindsight I would not have Try to remove those big bundles of cables What I would have done instead is to trim and terminate them And not touch the board at all Cutting the wires longer would have meant that I didn't wouldn't have needed to solder on wires myself The issue with terminating them is that there's quite a lot Like this is the bundle from just the the The motherboard supply socket alone and there's Four five Six auxiliary supplies for Uh hard drives and things And they would all need terminating safely not just letting like bare ends dangle But that's doable. I mean it's not particularly difficult The simplest way is to cut them off clean Fold the end over and wrap with insulating tape and then you can bundle them all together with insulating tape Yeah But this worked and it hasn't exploded yet and It's not making hot smells yet And it has a nice led. I could have used a bigger resistor for that actually it's quite bright Yeah, that will power various bits of electronics For a good while for me And in fact having everything coming off one side of the box means it will very neatly Slot in over this side of my workbench where it's out of the way I can possibly even put things underneath it, but not on top of it Okay, that's a success so far If anything burns down, I will try to capture some videotape for you. Oh good. That does turn off