Amiga 1200 graphic corruption

[suppah]

Hello,

my friend just bought an Amiga 1200 (motherboard revision 2B) which behaves very strangely. We have tested some games and in the games it works perfectly but as soon as we use a display resolution like DBLNTSC or DBLPAL after 15-20 minute the Amiga is powered on the display gets corrupted.

The way the corruption happens very is very similar to this:

[ Show youtube player ]

But happens ONLY in "advanced" resolutions like DBLPal or DBLNTSC. When the corruption manifests if we switch to PAL, PAL-HIRES, etc etc, it works perfectly, if we get back to DBLPAL/DBLNTSC the corruption starts again.

The motherboard still has the two evil caps E123C and E125C installed but apart from not letting one ACA accelerator board work im not really sure if these caps can also cause this display graphics corruption...

Lisa chip gets mildly hot, you can put your finger on it and feel some heat but it's not very hot, you can keep your finger on it without problems.

Have any idea ? We are not sure if to send it to recapping and timer fixing or giving the Amiga back to the seller.

[frank_b]

Mine does that. It's an Escom model. I leave it for 10 minutes and it is fine.

[Krashan]

Originally Posted by suppah

as soon as we use a display resolution like DBLNTSC or DBLPAL after 15-20 minute the Amiga is powered on the display gets corrupted.

Try this: https://rastport.com/techblog/removi...splay-trashes/

[suppah]

Originally Posted by Krashan

Try this: https://rastport.com/techblog/removi...splay-trashes/

Yes, thanks! This thing is sooo absurd... I remember reading it ages ago but I forgot about it. Told my friend and he changed the palette to darker the colors and no more corruption. The mobo fix looks easy enough.

It was a shame because the 1200 is REALLY MINT, on the outside, the inside, the floppy is in an awesome condition too. The original seller used it for weeks and put it away since now...