The Punisher PCB bootleg

[Jacmar]

got any pictures of the issue?

 

[Retro Marky]

I wish I could. The issue is impossible to photograph as it comes and goes as the screen refreshes. It's like a horizontal ghosting but the colours are not refreshing quite as they should. Not sure even where the video is being generated.

 

[Retro Marky]

If I could figure out where to start looking with the video, thatd help. I don't think it's a RAM issue but could be video ram of some sort?

 

[Jacmar]

Do you mean during the attract mode Central Park scene transitions?
Where you get briefly incorrect pictures displayed, remnants of previous scenes, or random graphics, sometimes for only a frame or two.
Some images remaining visible for too long after their scene ends, while others appear prematurely?
Some transitions briefly exposing unwanted graphics from neighbouring areas of the tilemaps, producing flashes of random tiles, lines and partially drawn pictures. and also instances where graphics appear with incorrect colours as the palette changed between scenes?
Do you mean all that ? If so that's just the bootleg being crap

 

[Neol]

Had a similar ghosting issue on a bootleg CPS1 board a while back, and it turned out to be a flaky trace near one of the custom graphic chips rather than the chip itself. Definitely grab a scope and check continuity around the custom logic before you start reflowing anything, especially since bootlegs can have some pretty sketchy trace work hidden under the solder mask.

 

[Retro Marky]

No, the attract mode is ok. It's more the gameplay. Almost like its something to do with the sprites moving and the background colours not quite keeping up

 

[Retro Marky]

Must admit, im new to this game so I can see why bootlegs are not a great idea. Especially as there are not schematics!

 

[Retro Marky]

Any idea where the palette swapping is done? I presume there are some logic ICs for that

 

[Jacmar]

If you've not already ...
Try another monitor/display to rule out analogue ghosting.
Check you've got a clean 5V supply , on IC's , not just at the JAMMA connector.
still got the issue, post a picture of your pcb

 

[Retro Marky]

OK will do. PSU is good but will double check all voltages. Ive got an adapter coming that will enable me to fine tune the sync signal as well so that might help rule things out. Prob take a few weeks so will keep you posted. Thanks
PS I have changed all the electrolytics but will look at swapping out the disc caps as well.

 

[Lurch666]

Make sure you have a good video GND as that can cause graphic issues.

 

[Retro Marky]

OK, will do ,thanks. Will update in a couple of weeks or if i get any changes!