Without a physical inspection and/or testing, there is no way to know for sure.

I would recommend:

a) Open it up and inspect it for deterioration of any components. You want to look for things like bulging or leaky capacitors, visible corrosion, melted plastics, etc.
b) Test for shorts and stable output voltages with a multimeter.

Agree ! Open it and inspect. Put a small load (a bad old HD that does spin up works well for this usually) as it should have a 1 amp minimum load on PSU for a proper voltage test.
Many 1990's PSU list the minimum amps on the label along with max amps....or you may be able to google the full PSU specs.

I don't have a multimeter but i know someone who probably does. When i first got the thing, i powered it on and it booted (except i didn't have an AT keyboard so i only got so far). I just don't know if it's gonna last any longer without blowing in my face.

FrAEnk wrote on 2024-11-11, 23:57:

I don't have a multimeter but i know someone who probably does. When i first got the thing, i powered it on and it booted (except i didn't have an AT keyboard so i only got so far). I just don't know if it's gonna last any longer without blowing in my face.

Ok, that is a good sign but do not try it again until you can take some measurements. You should open it (PSU) up and look it over, any bulging capacitor tops or brownish sludge around any is a bad sign.
Though some companies used a flex-epoxy around some parts so if you open the PSU take some pictures and attach them here....

Alright, Ill try to dig it out of my closet and get it open!

FrAEnk wrote on 2024-11-12, 21:50:

Alright, Ill try to dig it out of my closet and get it open!

I don't see any warning in the thread so please be careful if you *do* open up the power supply after it's been powered on or if it's been powered recently. The big capacitors can store a charge up to around 320 volts and if the PSU wasn't designed to bleed off that power then it may remain in the capacitors for a while after the PSU is powered down. So be aware that touching any of the traces connected to that capacitor could be hazardous potentially, especially since you have no way of checking the voltage without a multimeter.
However, just opening the top case to inspect the PSU while the power supply is unplugged should be fine, the potentially dangerous traces and capacitors legs would be still covered up inside the lower tray of the power supply. That way you can see if there's anything burnt, capacitor leakage or capacitors that are bulging, but since the system turned on already you're probably fine.

Additionally, please also be aware that the power switch of an AT power supply runs AC mains voltage through those wires when the PSU is plugged in and switched either on or off. Watch out for any loose insulation on those connectors if you're handling them while hooked up to power.

The quality of the PSU largely depends on the manufacturer, what make is it? I've got a few AT power supplies that were cheapy brands and my preference was to replace them with modern ATX supplies that have better safeties in place.

For testing the PSU out of the PC you could do what miketech does and run the PSU outside of the case running a couple of ideally dead hard drives for a load: https://youtu.be/e9m2KX_14_0?t=510

The PSU hasn’t been turned on for roughly half a year. When you said you replaced cheap power supplies with reliable ATX ones, that got me thinking because I have a spare ATX power supply but I don’t know how I’d connect it to the motherboard. As for the make, I don’t know, maybe someone could figure out in the attached image. Also sorry for trash iPod touch 7th gen quality.

Well it's got a CSA symbol so at least it won't burn your house down illegally 🤣

Been meaning to add that if you have a car voltage tester that does 6V too, it might have enough range on the scale for you to see whether it's in +/- 10% at 5v and 12V and connect backwards to check the negative 5 and 12. If it's a needle gauge one, or you scare up an old needle gauge analog multimeter, bonus! The thing about those is if you read the voltage and you can hear the needle buzzing or see it quivering, you definitely know it's got too much ripple.

Thanks! Tomorrow, ill go see if my dad has... well any of that. He might have a car voltage tester.

Looks like a Deer or equivalently cheap PSU. Neither the UL nor the CSA certification numbers lead to anywhere, so they may be either too old or counterfeit. So I guess it's best to open the PSU and post pictures here, as suggested. Do this with the power disconnected, of course. Other than that, old PSUs are usually pretty good about bleeding the mains cap(s) pretty quickly... so it should be a pretty safe endeavor.

My guess would be a PSU that is nothing too extraordinary... if not a little on the cheap side... but probably still adequate for an old AT build (since those don't really use that much power.)

That's cause it is a Deer. I'd recognize that warranty sticker anywhere.

PcBytes wrote on 2024-11-14, 00:48:

That's cause it is a Deer. I'd recognize that warranty sticker anywhere.

Hehe, yeah the warranty sticker is what made me think it's a Deer. Just wasn't 100% sure as it's been a while since I've encountered one.
Probably a half-way decent unit then, but likely with crap caps and no or very low-cost EMI/RFI filter.
A bunch of scrap PSU boards from a TV repair shop should be able to fill-in for the missing/low-budget EMI/RFI filter, and maybe the output caps too.

Not really. Last two AT Deer units I opened were gutless "B-side" units, with the orientation swapped around and some long ass AC inlet wiring to acommodate the wrong direction.

"Nothing runs like a Deer" ?

I finally got the PSU open (couldn’t get pictures unfortunately) but really, it was:

1. A little dusty.
2. No blown/leaking caps (thank god)

I couldn’t test the voltages because my dad can’t find his multimeter. It should be good to go though!

Personally i dont use easily replaced 'noname' ATX PSU's. I had one burn up and an other disturbing my power line network. I feel its not really worth the risk or effort. (But i have some old proprietary Compaq PSUs that work just fine.)

My take on it is, PSU might break other hardware if it fails, no biggy, but think about old PSUs like lighting a candle, dont leave them unattended.

Actually, Turns out my motherboard supports ATX power supplies so i guess i don't have to use that hunk of junk anymore. Thanks to all!

Joakim wrote on 2024-11-15, 21:30:

Personally i dont use easily replaced 'noname' ATX PSU's. I had one burn up and an other disturbing my power line network. I feel its not really worth the risk or effort. (But i have some old proprietary Compaq PSUs that work just fine.)

Well, the proprietary Compaq PSUs certainly aren't "noname" old crap. If anything, they were built much better than anything else at the time... in fact, some of them too well, to the point that these will outlast even the best PSUs available today.
Otherwise, I agree that it's not worth playing with cheap crap -real- noname PSUs - that is, installing them in a system and running them as-is. If you do have a bit of electronics knowledge though and know how to repair/upgrade/"propri-fy" these, you can actually end up with some pretty decent and very very reliable units. That's because most old PSUs, be it noname or legit stuff, are much simpler in nature and didn't really require "exotic" high-end parts to do their job... nor did they stress the parts inside them too much. So once recapped with high quality Japanese caps and any missing filtering components added back, they can provide many years of trouble-free service - possibly even longer than some of the better/best units available on the market today.

As for leaving old PSUs unattended - only if they weren't ever checked and/or recapped (if needed) before. Once I rebuild a PSU and test it (more or less properly), I generally trust it just as much, if not more, than new brand-name stuff from the store.