dead/dangerous psu? psu thermistor?

ceraf · Post by **ceraf** » Tue Aug 10, 2004 5:36 pm

My AOpen ATX-300GT seems to make some whining noise after I turn it off, and the pitch gradually goes lower. Then the sound completely stops and then I get a voltage feedback from the 12V and 5V lines of about 0.5V (I tested that). Does that mean that the psu is dangerous to use/dying? I already killed 2 motherboards with it.

Second question if the psu is unusable: the fan inside is connected to a small separate circuit board with some resistors, transistors, a small capacitor, and a thermal probe which goes onto the heatsink. then that circuit board is connected to the main circuit board by 2 wires, which I assume are for the fan. Can I cut this out and use it as a thermistor?

boy, electric circuitry is so fun and deadly to play around with.

dukla2000 · Post by **dukla2000** » Wed Aug 11, 2004 12:24 pm

ceraf wrote:I already killed 2 motherboards with it.

I would reckon that is reason enough to retire it! Which is a shame because AOpen are OEM FSP.

And yes, you can certainly reuse the fan and/or the 'noise-killer' circuit board. As there is no calibration/adjustment on it though mine are in the toolbox: I just wire fans direct to 5V or use a manual fan controller these days.

MonsterMac · Post by **MonsterMac** » Wed Aug 11, 2004 7:24 pm

if you've killed two motherboards with that PSU, i'd say it's time for a new one.

ceraf · Post by **ceraf** » Thu Aug 12, 2004 9:14 am

actually, I meant to say that the psu might have killed 2 motherboards, but they were pretty old already.

Putting that aside, I think ill be having fun ripping apart the power supply now.

larrymoencurly · Post by **larrymoencurly** » Fri Aug 13, 2004 10:35 pm

I have a Sparkle brand ATX-300GT, which should be identical to your Aopen, but I didn't blip up to 0.5V after I turned it off with either the front panel button or the switch on the rear, at least not for 30 seconds. I tested it only while it was connected to the mobo (ECS P4S5A2 -- doesn't use +12V for CPU power) and disk drives. I didn't hear any whistle or whine, but my CPU fan is kind of loud and my ears are plugged up today.

I 've heard other PSUs whine when turned off, including a 300W Antec SmartPower, but it didn't seem to hurt, and only when they whine during regular operation have I had problems.

dead/dangerous psu? psu thermistor?

dead/dangerous psu? psu thermistor?

Re: dead/dangerous psu? psu thermistor?