Amiga 500 PSU 312503-01 with screen noise

[spawnerbr]

Hi all.
I'm having a problem with an Amiga 500 PSU 312503-01. Using this PSU model I'm having some kind of noise on the RGB output. I tested with 3 other PSU and the image was very clean.

This is how the image is:



So, any idea about to fix this? A recap? Where can I find the caps list of this PSU model or an schematic? Thanks

[bender]

Hello!

I'm not sure if a recap will solve your issue or not, probably it will. but I have a couple of those same PSUs (Same part number 312503-01) and I replaced their caps a few months ago. They are both working fine, no issues at all.

The list I used is this (Sorry it is not properly aligned):

Número	Faradios	Volts	Mouser Part #

C7 or C5	220uF	200V	647-UVK2D221MHD

C23	470uF	35V	647-UVR1V471MPD1TD

C16	1uF	50V	710-860010672005

C17	1uF	50V	710-860010672005

c28	0.47uF	50V	710-860010672004

c25	10uF	50V	710-860010672009

c24	22uF	25V	647-UVR1E220MDD1TD

C19	220uF	25V	647-UVR1E221MPD

C11	1000uF	25V	647-UVR1E102MPD

C13	3300uF	10V	647-UVR1A332MHD

C14	3300uF	10V	647-UVR1A332MHD

C23 or C15	3300uF	10V	647-UVR1A332MHD

Still you may want to double check. I removed all caps from one of them and came up with the list. It worked fine for both.

The Mouser part# is just for the brand I bought, of course there are many options for that.

Hope this helps

Regards,
Efrén

[spawnerbr]

Originally Posted by bender

Número	Faradios	Volts	Mouser Part #

C7 or C5	220uF	200V	647-UVK2D221MHD

C23	470uF	35V	647-UVR1V471MPD1TD

C16	1uF	50V	710-860010672005

C17	1uF	50V	710-860010672005

c28	0.47uF	50V	710-860010672004

c25	10uF	50V	710-860010672009

c24	22uF	25V	647-UVR1E220MDD1TD

C19	220uF	25V	647-UVR1E221MPD

C11	1000uF	25V	647-UVR1E102MPD

C13	3300uF	10V	647-UVR1A332MHD

C14	3300uF	10V	647-UVR1A332MHD

C23 or C15	3300uF	10V	647-UVR1A332MHD

Thanks for the list. I read some of my caps on the PSU board and they are not the same of your list. This are the ones that I take note without remove them:

C6 / 250v 220uF
C18 / 50v 0.47uF
C21 / 25v 22uF
C23 / 16v 10uF
C25 / 25v 2200uF

Maybe the board inside is different? Mine is DSP-A500 REV-2 DVE 0388.

[bender]

Hello!

I just opened one and I think yes they are different. Mine has the legend "DVE DSP-128CON" on the small board that's perpendicular to the main board.

The "DSP-128CON" is also on the bottom part of the plastic case. right below the part number.

So yes... apparently Same Part Number but different board inside :S

Anyway... replacing them won't hurt and it may very well solve your issue

Regards,
Efrén

[turrican9]

One of my A600 PSUs gave some noise on the screen. Noticed it in a game. It also had this fishsmell to it. Fishsmell was worse as the PSU heated up. I recapped it, I couldn't see any CAP leakage but after the recap the fishsmell was gone and the noise aswell. So must have been some bad caps.

I have another A500 PSU which showed no signs of problems, but when recapping it I found a leaking cap.

I am in the process of recapping all my PSUs.

So it's most likely cap problems causing that noise on the screen.

[spawnerbr]

Originally Posted by turrican9

One of my A600 PSUs gave some noise on the screen. Noticed it in a game. It also had this fishsmell to it. Fishsmell was worse as the PSU heated up. I recapped it, I couldn't see any CAP leakage but after the recap the fishsmell was gone and the noise aswell. So must have been some bad caps.

I have another A500 PSU which showed no signs of problems, but when recapping it I found a leaking cap.

I am in the process of recapping all my PSUs.

So it's most likely cap problems causing that noise on the screen.

I did today the recap and the noise is still on de screen. Don't know what to do.

[spawnerbr]

I took note of all caps from this PSU model.

312503-01
DSP-A500 REV-2 DVE 0388

C6 250v 220uF
C13 16v 220uF
C15 10v 3300uF
C16 10v 3300uF
C18 50v 0,47uF
C20 25v 220uF
C21 25v 22uF
C22 50v 1uF
C23 16v 10uF
C24 10v 1000uF
C25 25v 2200uF

[turrican9]

Originally Posted by spawnerbr

I did today the recap and the noise is still on de screen. Don't know what to do.

Did you see or smell any leakage? If so, check for corroded traces/vias. On one of my A500 PSUs, the one where a small cap had leaked, the corrosion under it was quite bad and had corroded the via to the point it fell appart and lost contact with the trace as I unsoldered it.

[spawnerbr]

Originally Posted by turrican9

Did you see or smell any leakage? If so, check for corroded traces/vias. On one of my A500 PSUs, the one where a small cap had leaked, the corrosion under it was quite bad and had corroded the via to the point it fell appart and lost contact with the trace as I unsoldered it.

No leakage on the PCB. The PCB is very clean.