On computer PSUs what wears out other than capacitors

[Hogwild]

Hi everyone:

I have an 8 or 9-year-old Seasonic SS-430HB PSU. I'd like to put it to use, but I'm assuming the caps might go bad soon. If I replaced the caps, would that be enough to keep it going long-term, or are there other components on computer PSUs that die with age? What else, if anything, would I need to replace?

Thanks.

[cdev]

Fan may benefit from a tiny bit of lubrication or possibly bearings wearing might indicate replacement, possibly. It depends on the fan.

[Hogwild]

Thanks. Yeah, I knew about that. True on most moving/mechanical parts. So far, the fan sounds as quiet as it did the day i got it. It's a Yate Loon, so no surprise. Will resistors or any other components need replacing?

[thermistor-guy]

Hi everyone:

I have an 8 or 9-year-old Seasonic SS-430HB PSU. I'd like to put it to use, but I'm assuming the caps might go bad soon. If I replaced the caps, would that be enough to keep it going long-term, or are there other components on computer PSUs that die with age? What else, if anything, would I need to replace?

Thanks.

I'd look carefully at the heatsinking arrangements, and where practical, replace any thermal paste or pads used. They become less effective with age, especially after 8 or 9 years, either
due to slow chemical changes, or due to thermal cycling that loosens the interface layers (loose contact = high thermal resistance).

[cdev]

Inspect them and all other passive components (capacitors, inductors) closely and replace any that show even the slightest sign of cracking or breaking in any way. Similarly for any solder joints, redo any solder joints that look iffy. Since you are in there already.

Specifically with power supplies, sometimes they have footprints for missing components that might be present in better models. Sometimes you might want to figure out what those other components are and add them. More or better capacitors might reduce RFI for example, but make sure you know what you are doing and that it wont cause problems. Especially on the mains voltage side of the supply. Specific laws likely apply to lines powered devices on the line-facing side. Make sure you understand them and comply with them or leave that part of the supply alone.

Thanks. Yeah, I knew about that. True on most moving/mechanical parts. So far, the fan sounds as quiet as it did the day i got it. It's a Yate Loon, so no surprise. Will resistors or any other components need replacing?

[Hogwild]

Thanks. If a resistor is bad, will it be obvious, or not necesarily? I hadn't thought of thermal material. That's a good idea. Where do I buy replacement thermal material? Does it matter what kind?

[amyk]

Seasonic is a pretty good brand so I wouldn't worry about doing any servicing beyond cleaning out the dust and lubricating the fan(s).

[Wan Huang Luo]

Methinks you're a little too cautious. I'd just whack that PSU in and use it with confidence.

[wraper]

Hi everyone:

I have an 8 or 9-year-old Seasonic SS-430HB PSU. I'd like to put it to use, but I'm assuming the caps might go bad soon. If I replaced the caps, would that be enough to keep it going long-term, or are there other components on computer PSUs that die with age? What else, if anything, would I need to replace?

Thanks.

I'd look carefully at the heatsinking arrangements, and where practical, replace any thermal paste or pads used. They become less effective with age, especially after 8 or 9 years, either
due to slow chemical changes, or due to thermal cycling that loosens the interface layers (loose contact = high thermal resistance).

That is some very bad advice. And it would be somewhat valid only if some very bad thermal paste was used. Most likely there are just thermal pads anyway.

[james_s]

Agreed, I have never replaced thermal paste unless I had to take a part out anyway. You are far more likely to damage something trying to replace the paste than by just leaving it alone. Personally I would just blow the dust out of the thing, inspect the fan and look for any bulging or leaky capacitors. If everything looks ok then just use it, the more you mess with it, the more opportunities you have to screw something up. I have seen a LOT of good usable gear ruined by people trying to fix what wasn't broken.

[In Vacuo Veritas]

Methinks you're a little too cautious. I'd just whack that PSU in and use it with confidence.

Good Lord yes! The amount of people getting a legit psychological disorder every time they see a capacitor is incredible. What next? Will they be on Dr Phil?

[GreyWoolfe]

Methinks you're a little too cautious. I'd just whack that PSU in and use it with confidence.

Good Lord yes! The amount of people getting a legit psychological disorder every time they see a capacitor is incredible. What next? Will they be on Dr Phil?

No, Jerry Sprinter.  He loves psychological disorders.

[Wan Huang Luo]

Agreed, I have never replaced thermal paste unless I had to take a part out anyway. You are far more likely to damage something trying to replace the paste than by just leaving it alone. Personally I would just blow the dust out of the thing, inspect the fan and look for any bulging or leaky capacitors. If everything looks ok then just use it, the more you mess with it, the more opportunities you have to screw something up. I have seen a LOT of good usable gear ruined by people trying to fix what wasn't broken.

Fix it till its broken. Trap for young players!

[ogden]

Snubber resistor or it's solder joints may become point of failure.

[Rasz]

dont forget piston return springs

[SoundTech-LG]

Any mechanically attached component that is mounted off-board to heatsinks etc....  such as regulators, transistors, diodes. Check for cracked solder, or broken leads. Maybe big transformers have cracked solder rings too. Check and re-flow. Have fun!

[thermistor-guy]

Agreed, I have never replaced thermal paste unless I had to take a part out anyway. You are far more likely to damage something trying to replace the paste than by just leaving it alone. Personally I would just blow the dust out of the thing, inspect the fan and look for any bulging or leaky capacitors. If everything looks ok then just use it, the more you mess with it, the more opportunities you have to screw something up. I have seen a LOT of good usable gear ruined by people trying to fix what wasn't broken.

It depends on the person attempting the fix. I've never had a problem. But at the far end of the scale, we have folks here refurbishing/repairing 8.5 digit DVMs, which is beyond my current ability.

The OP didn't indicate his/her level of expertise. As a general rule, those who can be discouraged, should be discouraged.

But in answer to the OP's question - what wears out in PSUs over time - yes, the thermal interfaces do degrade.

[james_s]

I generally assume that if someone has to ask, then they probably shouldn't start trying to fix things that aren't broken yet. The people who have the expertise to replace parts with little risk of additional damage don't usually need to ask what parts they should replace. Now this is in no way criticizing people who are inexperienced, everyone has to start somewhere.

[Hogwild]

Okay, I decided to take some photos to see if anyone could spot anything I missed. The item is a bit hard to photograph, what with all the enclosed spaces, but I did my best to light it.

Anyone see anything that doesn't look good?

In the last shot is a piece of plastic with some goop on it. That fell off one of the coils as soon as I touched it. What is that goop, and I assume I should get some and remove old goop and apply a fresh coat?

Thanks

[Hogwild]

Here are a couple more, including the plastic piece that fell off.

[james_s]

The goop is just glue, the plastic piece is an insulating separator to prevent shorts to the metal case. You can stick it back on with a small dab of caulking or similar adhesive.

[Nusa]

If there's nothing wrong and it operates as expected, don't fix it! In the absence of symptoms, the only normal preventative maintenance is blowing out accumulated dust. Use it, or keep it on the shelf as a spare.

[Hogwild]

I blew out all the dust carefully. All caps at least appear to be fine. No burn marks, nothing else stands out. Thanks!

A related question: I have another ATX PSU here, labelled Alpha. This was put in at a store, I believe in 2014.  I can't find any reviews or teardowns of this PSU.

Here are some pics. Can anyone see anything that stands out as bad? It's still working fine. Haven't checked the rail voltages lately, but I thought I would add this to my friend's collection as a backup, just in case.

[Hogwild]

Here are a few more angles of the ALPHA PSU.

[james_s]

Looks like a really cheap one. Phenolic PCB, no-name Chinesium capacitors, and a few of those smaller caps look like they may be bulging at the top but it's hard to tell from the picture. If the capacitors are ok then it's probably ok to use, but it's certainly not a high end one.