Sprite ghosting... where to look after all rams check out good.

[sugreff]

Sprite ghosting... where to look after all rams check out good.

[vimeo]105929511[/vimeo]

EDIT: Turn your speakers down a little bit. There's a slight hum in the audio.. Sorry!

Replaced a few bad 6116's that were causing background sprites to mess up. Now I'm left with this ghosting issue. I'm 99% sure it was present before I addressed the bad ram. You can see it in the character and enemy sprites. It is a grey ghosting of the sprite.

There are no schematics for this game (Gemini Wing) and I was wondering where you guys would start. I have a probe but there is litrally no documentation (that I can find).

Adam

 

[kb0jjn]

[vimeo]105929511[/vimeo]

EDIT: Turn your speakers down a little bit. There's a slight hum in the audio.. Sorry!

Replaced a few bad 6116's that were causing background sprites to mess up. Now I'm left with this ghosting issue. I'm 99% sure it was present before I addressed the bad ram. You can see it in the character and enemy sprites. It is a grey ghosting of the sprite.

There are no schematics for this game (Gemini Wing) and I was wondering where you guys would start. I have a probe but there is litrally no documentation (that I can find).

Adam

It is like the image is doubled and the double is what is ghosting. I would look at counters, shift registers, or clock circuits. What is that game and what processor is it running? Just about anything that is going to from the sprite ram needs to be looked at.

EDIT:

Low voltage will cause sprite issues like that...What is the +5 at?

 

[channelmanic]

Check for a missing address signal on one of the RAMs you replaced.

 

[sugreff]

Thanks for the ideas guys. I'm going to start back at this hopefully this weekend and will post results. Unfortunately my probe died on me and I'm waiting on the replacement.

Adam

 

[sugreff]

EDIT:

Low voltage will cause sprite issues like that...What is the +5 at?

I'm showing 5.05 on the harness and between 5.02-5.04 on the PCB. I tried jacking it up to 5.125 and still getting the same. Has to be an IC.

Adam