Amiga 600 PSU -12v line is reading ~-1v

Zxspectrum16k · 21 July 2019, 04:31

I've tested each Pin on the power connector of my 600s PSU, they all seem ok except for the -12v pin which is oscillating between ~-1.5v and -0.5v g0ing from -1.5v to -0.5v and back to -1.5v in around 1 second.

Visual inspection of the PSU components doesn't show any obvious problems with any components.

Any thoughts on what the issue might be, where to start looking?

PSU is a 391 029-05 (possibly an Australasian revision?) with the "391 029-03 rev A" looking to be the closest match.

whitegiant89 · 21 July 2019, 06:13

Having pulled my 3 a500 psu's apart after sitting for 20 years, i found quite a few
capictors had leaked. they looked perfect on the top but had bulged and leaked from the bottom. I just Finished recapping the and they are putting out the right voltage now.

Zxspectrum16k · 21 July 2019, 06:47

Thanks, good call. I'll look at recapping for sure then. Just to be certain the caps are good going forward

21 July 2019, 04:31	#1
Zxspectrum16k Registered User Join Date: Feb 2019 Location: Lower Hutt Posts: 5	Amiga 600 PSU -12v line is oscillating between -1.5v and -0.5v I've tested each Pin on the power connector of my 600s PSU, they all seem ok except for the -12v pin which is oscillating between ~-1.5v and -0.5v g0ing from -1.5v to -0.5v and back to -1.5v in around 1 second. Visual inspection of the PSU components doesn't show any obvious problems with any components. Any thoughts on what the issue might be, where to start looking? PSU is a 391 029-05 (possibly an Australasian revision?) with the "391 029-03 rev A" looking to be the closest match. Last edited by Zxspectrum16k; 21 July 2019 at 05:21. Reason: updated with PSU revision info

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21 July 2019, 06:13	#2
whitegiant89 Lone CBM user Join Date: Mar 2007 Location: Atherton / Australia Age: 52 Posts: 148	Having pulled my 3 a500 psu's apart after sitting for 20 years, i found quite a few capictors had leaked. they looked perfect on the top but had bulged and leaked from the bottom. I just Finished recapping the and they are putting out the right voltage now.

21 July 2019, 06:47	#3
Zxspectrum16k Registered User Join Date: Feb 2019 Location: Lower Hutt Posts: 5	Thanks, good call. I'll look at recapping for sure then. Just to be certain the caps are good going forward

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