Thinking about repairing a dead PSU

[ProjectBox153]

I've got a dead Thermaltake 850W PSU that I would like to revive if at all possible. It's not going into a computer of any importance if it does end up working. The fuse inside is fine, the power switch seems to be working fine, and there's nothing wrong with any of the internal wiring that I have checked so far. When I attempt to turn it on I get nothing at all. No fan movement, no noise, absolutely nothing. What should I check first, and what could have caused such a failure?

 

EDIT: Is this financially worth it? No. Is it worth it to me? Yes. I did not ask if it was worth trying to repair a dead PSU. I am very well aware of the hazards associated with 120V AC and working inside a power supply. Am I an expert? No, but that's why I'm asking here. Everyone learns in one way or another, and this is my way. Thank you to everyone who wants to look out for my safety and well-being.

[ProjectBox153]

Oh, and as an added note: none of the components that were attached to the PSU when it failed are bad in any way. I'll list the specs below for reference, but every part of the computer is still fine. It's actually been running 24/7 with a different PSU with absolutely no issues. 

 

System specs:

Spoiler

Intel Core i7-2600 (4C/8T), 16GB DDR3, ASUS P8Z68-V/GEN3, Zotac GeForce GTX 550 Ti, 240GB SATA SSD, various fans

 

[emosun]

3 minutes ago, ProjectBox153 said:

It's not going into a computer of any importance

is the building the computer is in important? and or is the building worth less than about 60$ ( the cost of a replacement unit)

[ProjectBox153]

1 minute ago, emosun said:

is the building the computer is in important? and or is the building worth less than about 60$ ( the cost of a replacement unit)

The power supply won't be used in any particular computer if it's ever revived. I have already replaced it, but I'd like to fix the dead unit that's been sitting around since September.

[--SID--]

What's the exact model of the Thermaltake psu?

[ProjectBox153]

2 minutes ago, --SID-- said:

What's the exact model of the Thermaltake psu?

I think it's the TR2 RX 850W if I'm remembering right. 

[Dutch_Master]

Unless you know what you're doing, I strongly recommend to recycle that PSU. The fact you're asking this question in the first place indicates you'd best not tamper with the insides of the PSU.

 

No offence, but PSUs are dangerous (potentially deadly) things in the hands of an experimental layman. Yes I know it's tempting, but there's a reason it stopped working in the first place.

[emosun]

1 minute ago, ProjectBox153 said:

The power supply won't be used in any particular computer if it's ever revived. I have already replaced it, but I'd like to fix the dead unit that's been sitting around since September.

I'd really recommend tossing it as high AC voltage shouldn't be messed with. 12v dc isn't really that scary but wall AC really isn't worth the risk.

If it were just a regular desk lamp then yeah those are pretty simple to fix. Or even something like a blender or power tool is a pretty easy fix. But i don;t think you should open a power supply and mess around with it under any financial situation.

[emosun]

2 minutes ago, Dutch_Master said:

The fact you're asking this question in the first place indicates you'd best not tamper with the insides of the PSU

i was actually thinking this exact same thing.

[ProjectBox153]

Look, I'm not asking about whether or not it's worth diagnosing it or repairing it. It's worth it to me. I got it for free, it's my PSU, it's my time spent on it, and I want to. That's more than enough justification for wanting to work on it. 

 

4 minutes ago, Dutch_Master said:

Unless you know what you're doing, I strongly recommend to recycle that PSU. The fact you're asking this question in the first place indicates you'd best not tamper with the insides of the PSU.

 

No offence, but PSUs are dangerous (potentially deadly) things in the hands of an experimental layman. Yes I know it's tempting, but there's a reason it stopped working in the first place.

Thanks, but I'm fine. I have worked on power supplies before, but they've always been older units. I am perfectly comfortable working inside a PSU. I understand that they can be dangerous, but I am perfectly capable of working on one. I am just trying to get ideas as to what may have gone wrong.

 

4 minutes ago, emosun said:

I'd really recommend tossing it as high AC voltage shouldn't be messed with. 12v dc isn't really that scary but wall AC really isn't worth the risk.

If it were just a regular desk lamp then yeah those are pretty simple to fix. Or even something like a blender or power tool is a pretty easy fix. But i don;t think you should open a power supply and mess around with it under any financial situation.

I'm comfortable working on these things. I've done so in the past, but not on units this new. It's not a matter of not being able to pay for a replacement. I have already gotten a replacement. I work on electronics as a hobby, and I'm just trying to get ideas for what to investigate. 

 

4 minutes ago, Dutch_Master said:

The fact you're asking this question in the first place indicates you'd best not tamper with the insides of the PSU.

Thanks for the assumption that I don't know what I'm doing. 

[Bitter]

Do not waste your time on it, if it's anything like the 750W unit from the same lineup it's trash pure and simple. The 750W unit couldn't even put out 600W and stick to ATX power specs and when pushed past 600W it would overheat and trip off until it cooled down. The 850W is cut from the same cloth. They're worth about $4 in scrap at the moment even if they do work. Move on, buy something else. The terrible ripple in those units is likely to either outright kill components over time or at best make the system unstable at higher power loads.

[ProjectBox153]

Just now, Bitter said:

Do not waste your time on it, if it's anything like the 750W unit from the same lineup it's trash pure and simple. The 750W unit couldn't even put out 600W and stick to ATX power specs and when pushed past 600W it would overheat and trip off until it cooled down. The 850W is cut from the same cloth. They're worth about $4 in scrap at the moment even if they do work. Move on, buy something else. The terrible ripple in those units is likely to either outright kill components over time or at best make the system unstable at higher power loads.

It likely won't even be powering a computer if I do fix it. Again, as stated in my above comments, I know that it isn't worth it. Really, I do! It's all for a bit of fun. 

[IcarusLSC]

7 hours ago, ProjectBox153 said:

It likely won't even be powering a computer if I do fix it. Again, as stated in my above comments, I know that it isn't worth it. Really, I do! It's all for a bit of fun. 

Then why are you asking? Just do it if you want, sounds like your going to anyways...

 

/thread

[ProjectBox153]

18 minutes ago, IcarusLSC said:

Then why are you asking? Just do it if you want, sounds like your going to anyways...

 

/thread

I am asking in order to get ideas of what to check. I don't know why that has been so hard. 

[Archer42]

IMO if you really want to learn start with understanding how PSU works, which components do what, and how said components work. Without this your attempts at fixing it are doomed to fail (and are hazardous), and if you already knew this you would not be asking questions like this (and that's why you get responses like "do not try").

Then try to search for schematics, or if unable to find it just try to identify things inside the PSU. PSU-s are not that complex, should not be that hard if you know what to look at.

Then start checking everything step by step.

All this is pretty safe as you do not need to even think about plugging the PSU in.

When you get to that point though - be aware, even when you unplug it you can still get a nasty shock from capacitors inside, and those same capacitors can kill the tools you are using, so you need to safely discharge those each time after plugging it in.

In general yes, everyone needs to start somewhere, but when working with high voltage going in blind is plain stupid - you need certain level of understanding first, which you get by reading, not randomly poking around the PSU...

[AngryBeaver]

10 hours ago, ProjectBox153 said:

I've got a dead Thermaltake 850W PSU that I would like to revive if at all possible. It's not going into a computer of any importance if it does end up working. The fuse inside is fine, the power switch seems to be working fine, and there's nothing wrong with any of the internal wiring that I have checked so far. When I attempt to turn it on I get nothing at all. No fan movement, no noise, absolutely nothing. What should I check first, and what could have caused such a failure?

 

EDIT: Is this financially worth it? No. Is it worth it to me? Yes. I did not ask if it was worth trying to repair a dead PSU. I am very well aware of the hazards associated with 120V AC and working inside a power supply. Am I an expert? No, but that's why I'm asking here. Everyone learns in one way or another, and this is my way. Thank you to everyone who wants to look out for my safety and well-being.

You do understand that things inside your PSU hold a charge and can 100% kill you. Which is why you should always let it be done by professionals with the correct gear.

[ProjectBox153]

11 minutes ago, AngryBeaver said:

You do understand that things inside your PSU hold a charge and can 100% kill you. Which is why you should always let it be done by professionals with the correct gear.

I really don't understand how many times I have to explain this. I KNOW THE HAZARDS OF WORKING WITH HIGH VOLTAGE EQUIPMENT (INCLUDING CAPACITORS). 

 

34 minutes ago, Archer42 said:

IMO if you really want to learn start with understanding how PSU works, which components do what, and how said components work. Without this your attempts at fixing it are doomed to fail (and are hazardous), and if you already knew this you would not be asking questions like this (and that's why you get responses like "do not try").

Then try to search for schematics, or if unable to find it just try to identify things inside the PSU. PSU-s are not that complex, should not be that hard if you know what to look at.

Then start checking everything step by step.

All this is pretty safe as you do not need to even think about plugging the PSU in.

When you get to that point though - be aware, even when you unplug it you can still get a nasty shock from capacitors inside, and those same capacitors can kill the tools you are using, so you need to safely discharge those each time after plugging it in.

In general yes, everyone needs to start somewhere, but when working with high voltage going in blind is plain stupid - you need certain level of understanding first, which you get by reading, not randomly poking around the PSU...

I wouldn't be randomly poking around in the PSU. My entire point of making this post was to ask for ideas about what people think may have gone wrong to give me a starting point. I know how to test things. I know how to discharge capacitors. I know how to work on things like this - I'm just asking for ideas. Based on the other responses I've gotten I don't think I'm going to get any good thoughts though. 

[Archer42]

1 minute ago, ProjectBox153 said:

I wouldn't be randomly poking around in the PSU. My entire point of making this post was to ask for ideas about what people think may have gone wrong to give me a starting point. I know how to test things. I know how to discharge capacitors. I know how to work on things like this - I'm just asking for ideas. Based on the other responses I've gotten I don't think I'm going to get any good thoughts though. 

Then what's the question? Because this statement contradicts your initial post.

May be start with describing what you have done already?

Also making guesses here is 100% pointless - it'll only throw you on a wild goose chase, you have to methodically test everything, if you know how it takes less time then it took to discuss it here.

[ProjectBox153]

Just now, Archer42 said:

Then what's the question? Because this statement contradicts your initial post.

May be start with describing what you have done already?

Also making guesses here is 100% pointless - it'll only throw you on a wild goose chase, you have to methodically test everything, if you know how it takes less time then it took to discuss it here.

Never mind. My question is literally in the comment you quoted. 

[Windows7ge]

This would be a general run down of how I might go about troubleshooting a PSU.

1. Start with a visual inspection. Any shit-stains? Good place to start.
2. Give it a sniff test. If something smells burnt look for blown caps, cracked transistors, or anything like looks like it let out the magic smoke.
3. Grab a multi-meter and test for a short to ground on the output rails. This would trip over-current protection instantly. If it yields nothing check for a short on the input side.
4. If none of these show results then you might have to start probing the board with Power connected and see where it gets lost. Many PSUs operate off a relay that gets tripped when PS_ON is shorted to ground. The circuit responsible for this could be bad or the relay may have failed. It's also possible over-current protection is somehow stuck on and isn't resetting.

If none of these show results you might have to desolder the input caps and start checking that they all register the correct uF. Past that I'm not sure where to go. I'd probably solder a wire across the relay terminals and just see what blows up.  Be like "Yep, there's your problem!".

[ProjectBox153]

3 minutes ago, Windows7ge said:

This would be a general run down of how I might go about troubleshooting a PSU.

1. Start with a visual inspection. Any shit-stains? Good place to start.
2. Give it a sniff test. If something smells burnt look for blown caps, cracked transistors, or anything like looks like it let out the magic smoke.
3. Grab a multi-meter and test for a short to ground on the output rails. This would trip over-current protection instantly. If it yields nothing check for a short on the input side.
4. If none of these show results then you might have to start probing the board with Power connected and see where it gets lost. Many PSUs operate off a relay that gets tripped when PS_ON is shorted to ground. The circuit responsible for this could be bad or the relay may have failed. It's also possible over-current protection is somehow stuck on and isn't resetting.

If none of these show results you might have to desolder the input caps and start checking that they all register the correct uF. Past that I'm not sure where to go. I'd probably solder a wire across the relay terminals and just see what blows up.  Be like "Yep, there's your problem!".

Thanks, a helpful response. I haven't looked at it too much yet, but I didn't see any bad caps yet. It's just full of dust. No smell either. I'll look into it some more later, but thanks for the advice.

[AngryBeaver]

9 hours ago, ProjectBox153 said:

I really don't understand how many times I have to explain this. I KNOW THE HAZARDS OF WORKING WITH HIGH VOLTAGE EQUIPMENT (INCLUDING CAPACITORS).

If this was true you would know better than fiddling with a cheap PSU for no good reason. Even more so when you don't even plan to use it or make it functional.

 

When I was younger I worked in a high voltage lab that tested line workers gear.. which ranged from Low voltage PPE to items designed to protect from cross state power lines. We are talking voltages so high that even with PPE any humidity or sweat would cause the power to ark over their skin which was very unpleasant and left sunburn like places (yet was completely safe).

 

So if you were serious about doing this properly you would have a solid plan in place for doing a slow drain of the caps. A lot of people think you can just arc across the caps with a screwdriver which outside of being dangerous can also fuse the screwdriver to the caps creating a new issue.

 

In any case you will do what you want, but the risk vs reward is non-existent. If you want to fiddle with items like this it is best you take a course and/or do an apprenticeship to learn the RIGHT way.

[ProjectBox153]

26 minutes ago, AngryBeaver said:

If this was true you would know better than fiddling with a cheap PSU for no good reason. Even more so when you don't even plan to use it or make it functional.

Where did you get the idea that I'm not going to use it if I get it working again? Also, I do have a good reason: I WANT TO. How much justification does everyone need on here? I'm sorry, but I'm just tired of everyone on here assuming I can't safely do something. Looks like I'll be going about this with less help than I hoped for. 

[AngryBeaver]

45 minutes ago, ProjectBox153 said:

Where did you get the idea that I'm not going to use it if I get it working again? Also, I do have a good reason: I WANT TO. How much justification does everyone need on here? I'm sorry, but I'm just tired of everyone on here assuming I can't safely do something. Looks like I'll be going about this with less help than I hoped for. 

Less help? Noone is going to encourage you to do something that could get you killed. Are you just unable to afford a new one? If that is the case ping me where you located and let's figure out a better solution.

[ProjectBox153]

1 hour ago, AngryBeaver said:

Less help? Noone is going to encourage you to do something that could get you killed. Are you just unable to afford a new one? If that is the case ping me where you located and let's figure out a better solution.

I've already replaced it with a different PSU. That's not the point. The point is that I have this PSU, it's broken, and I want to figure out why. Is it dangerous? Yes, of course it is. Nearly everyone is ignoring what I am saying. It's just something I want to do because I have the time, I have the knowledge to do things safely, and I want to. All I was asking for is a bit of guidance for what things are likely to fail first, or what non-obvious things should I look for, or what might have caused this in the first place. 

I appreciate everyone trying to look out for my safety, I really do. I also appreciate your offer to help me replace the PSU. I already replaced it with a spare Dell 750W PSU that is slightly too tall to fit properly.