PP2 Graphic Glitch (...yah, I know...)

steph

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...this has been discussed to death before...

http://forums.arcade-museum.com/showthread.php?t=125079

but I too am getting graphic problems with the foreground graphics
(cars, signs, etc...)

And I also did some Googling and found an Atari Tech note which said
that problems with the foreground objects
can be caused by problems with Horizontal Address counter chips (74LS161)
located at 9H, 9K, 10H, 10J, 10K and 10L .

So can anyone confirm that I'm looking at the right area,
or am I way out in left field ... ?

Here are some pics...

Let me know.

Thanks,
Steph
 

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That's not considered the "background". In the Pole Position series case.....background means...the clouds in the sky, mountains in the distance, cities in the distance, etc. Your issue looks like RAM. I'd start investigating what the manual calls "big cars and signs"...or something close to that. I (think) the RAM are 2148s (or 2149s or 2147s). Sorry, no manual close at the moment....and Atari PDFs are a nightmare on my laptop. The RAM are usually not socketed. I'd also check the ROMs in this area.

Edward
 
RAMs or dirty legs on a custom chip that handles the RAM data. You are missing some of the data.
 
RAMs or dirty legs on a custom chip that handles the RAM data. You are missing some of the data.

Is the RAM not for the video pixels on the screen ?

If so, I would have thought that if the problem was RAM,
I'd have the problem on the same AREA on the screen all the time
regardless of what was displayed in that area.

My problems is with the "sprites" (...to use an old Commodore term... ).
which is really only with the moving graphics (cars, signs, etc...)

The track and background (mountains, etc...) are always fine.

But I'll try re-seating the RAM anyways,
... PP is so flaky, it could be anything ! ;-)

Thanks,
Steph
 
????

I know...

My post said I was having problems with " FOREground" graphics...


;-)

Steph

Sorry....brain fart. Everything else I said still applies. I dug out a manual....the RAM are 9F and 10F. The custom is at 13H....and all the ROMs (and one PROM) below/beside the 13H custom. This is where your problem probably lies (or in some of these chips support logic).

Happy hunting :)
Edward
 
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