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Bench testing AA15830 from IIcx

C

ClintonGoodfellow

6502
Hi,

The rifa's went in my IIcx astec power supply, machine is now totally dead, wont turn on.

Have ordered the replacement caps and wondered if there was a safe way to start the psu on the bench for testing of output voltages much like how you would start an atx one.

Have ordered the full set of caps from console5 so should hopefully sort things. I find it strange however it being totally dead when the rifas blew as i thought these were more for mains filtering.

Cheers.
 
They are - if the PSU is totally dead when the RIFAs went, something else has gone wrong with it. Though it may just be the fuse and a fluke of the way the RIFAs went.

You should be able to power it up on the bench by doing something similar that you'd do with ATX ones - take the soft power pin high using the trickle voltage (on macs it goes high, not low like it does for ATX). I can't remember the pinout for the IIcx off the top of my head, though, I'm afraid
 
Cheers, will test this in the morning before i attempt recapping. Have seen the +5v continuous and the pfw pins, thanks for confirming it should be safe to bridge. Hopefully can sort it as its a great wee machine. Will report back.
 
You need to put a load of about 0.75 A on the 5V rail. Otherwise the power supply may fail to output the correct voltages.
 
Will def do that if I can get it going.

Had a chance this morning to test for trickle, showing 5v, joining to pfw fails to start the psu. Can confirm the fuses are fine and power is getting around the mains side of the board. Kinda grubby inside and can see a couple bulging caps along with the blown rifa. Will change these out and see where we are.
 
Now you have me second guessing myself... I think we need confirmation from someone else. Unfortunately my PSU is not in a position for me to look directly.
 
I searched the interwebs for another image of R325, but all were blurry so I took apart my PSU. I took another image and it looks red here; it also looks red when looking at the resistor with my eyes.

IMG_6052.jpg
 
I have some old images from a couple of different angles. It looks like brown, black, black, gold. But I'm not totally sure on the blacks. They could be blue. I'll see if I can get a better view tomorrow.

r322-2.jpgr322-3.jpg
 
Pulled that resistor, it was showing as a 10ohm right enough. Replaced it whilst it was out.

Several of the caps were well past their best, showing signs of leakage/swelling etc. All were replaced along with the filter caps. PSU now soft starts with the jumper.

Put the psu back in the machine and all is well, machine starts again now. So all clear hopefully for a few more years.

I still haven’t replaced that snipped resistor though as it was working beforehand. Will continue testing and look toward replacing it, still a bit odd, but we never know the history of these things.

Cheers
 
ClintonGoodfellow said:
Put the psu back in the machine and all is well, machine starts again now. So all clear hopefully for a few more years.
Click to expand...

Good stuff! Well done.

ClintonGoodfellow said:
I still haven’t replaced that snipped resistor though as it was working beforehand.
Click to expand...

Yeah - to me the snips look pretty neat, like it was done intentionally. It doesn't look like a blown part or an accident. If it's working, it might be best not to fiddle with it unless you can work out why.
 
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