RGB graphic messedup (PCE)

Hi, sorry if I'm asking help for a PCE problem, but I'm sure the best tekkie are around here ..
In case please mod, trash this to oblivion!

I have a DUO, modded with RGB output, taken straight from the chip.
I must admit I didn't used it for years, and now I think I have a problem..

all games (which works fine in another PCE), cd or hucard or even the boot menu, displays a sort of "incomplete" glitching graphic, like a color is missing (white, but only in certain "layers"?), while the rest is crisp and solid as common RGB:



it's strange that it is not uniform and evenly distributed, and like flipping:


when the image changes, *it appear as it should be* for a sec, just before the new image comes in..(?)

I checked mod soldering traces, and they are fine, even glued near the processor.
the only thing is that I lost the modder av cable so I was using a neo one.
Following the genesis/neo pinout, the 8pin connector placed by the tekkie on the duo, seems to follow r,g,b,+5 and composite pins.
I made a cable from the scratch, just to be sure without audio.

any chance this could be solved? Could it be a wellknown problem? (caps!? anyway even after 15min nothing changes..)


Thanks!!!

Looks like a broken trace.

Thanks, I tried a general view but it seems all ok.
Btw no oxid or dirt grown during the years, the cd itself is perfect, and can still read without problems the games.
The system was good years ago, and was just on the box for a "long sleep", no incidents or misuse.

some specific component could be deteriorated?

About bad traces, is there a logic behind this kind of behaviour, which could lead to a specific part to lookup?


I would really avoid to trash that console, it is in great shape, and repairing broken stuff leaves you in that mood... satisfaction, you know.

If it isn't a trace then could be a failing component.

Xian Xi said:

If it isn't a trace then could be a failing component.

Click to expand...

Yes I thought so.

Try checking the grounds.
Make sure the sync (pin 44) is secure.

Are you using any sort of RGB amp?
Have you flipped thorugh all the setting on the TV?

NeoGeeO said:

Try checking the grounds.
Make sure the sync (pin 44) is secure.

Are you using any sort of RGB amp?
Have you flipped thorugh all the setting on the TV?

Click to expand...

hi thanks, grounds are ok, i verified processor pins too, with a multimeter continuity test (far as I can go, but I have a logic probe somewhere, need some guidance for that)

There is no rgb amp, the rgb and signals comes straight from the cpu.


Tried tv settings, changed tv too.

I'll post some pic more, as it seems to me a chipset problem (the first image is actually missing "pieces" of colors, like a cromakey effect)

Is like a graphic/white background layer is missing, except for that, graphic is crisp stable and solid.

The fact that ie title screen are ok for just a sec when changing could mean voltage problem!?