Power Unit
Is it a fossil? Is it an experiment in furriness? No..it’s a power supply..!
This was perhaps the most alarming discovery. On the outside, Jem’s PSU showed some surface dust…light, and easily wiped off. Don’t be lulled into a false sense of security though. These things are rarely, if ever opened up after leaving the factory. There are good reasons for this..minor things like electrocution are worth a mention. However..any PSU is safe once it’s been totally unplugged from the mains and the PC, and has been left for a few hours at least to lose the charge stored in it’s capacitors.
I’ve done several PSU’s before..and I decided to go ahead and crack this one open as well. I have spares. So..paper down on the carpet, and out with the screwdrivers.
One 1990 vintage AT format, 300 watt power supply unit. Recently running 24 hours a day, 7 days a week, for several years. Time for a clean, no?
The PSU..uncovered..literally..;) 6 screws, and it’s off. See the small layer of dust on it? Not too bad, eh?
Ah..this isn’t good. What you can see here is the main PCB of the power unit. 240Volts flows through parts of this..it generates a lot of heat, and as you can see..it’s plastered with dust.
This is a top down view of the PSU power transistors. You can see the 2 alloy heatsinks that generate 90% of the heat inside. These should be clean to work at maximum effectiveness..now, are they clean? Nope.
A side view. you can see how thick the dust buildup is. This is quite scary when you consider that your PC has one of these, passing 240 volts and making heat, while you’re somewhere else.
The fan. The entire purpose of this is to suck air over the alloy heatsinks and cool them down. It’s been a long time since this has been an efficient process here..even the fan is clogging up.
The close up. ’nuff said. Yuk. Fire risk, I’d say..I’m amazed it still ran without overheating. Components have literally vanished underneath the dust and have no cooling at all. Clearly..this can’t continue. So…out with the paintbrush and vacuum cleaner again.
First things first. I unscrewed the fan from the PSU, and lifted it free so I could attack both sides with the paintbrush. It’s hard to clean a fan 100%..so get as much off as you can and as long as it shifts air..be happy. This is now pretty clean again.
This, believe it or not, is how well it cleaned up! You’re looking at the same part of the PSU as in the 3rd Picture down. It’s fiddly to get the brush inbetween the components..and it takes several tries. But..it’s worth it. All components are now visible! See how the alloy heatsinks shine..thats going to cool much better now.
This is the same part as picture 5! Even the really bad stuff came off to reveal an OK set of components underneath! I was frankly amazed at that. Much happier, and much safer. This PSU is now much cooler running and hopefully will have a long life ahead of it.