Roadblasters Graphical error

gcpowers

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Ive got some graphical errors on my Roadblasters. The graphics on the road in front of the car are missing as well as some of the background graphics. I checked and reseated all the ROMS. That was a long and tedious job but they all tested out ok. Ive also reseated all the other socketed chips. Any thoughts on what to try next?
 

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Just went through the 4 SLAG chips one by one but the problem did not change. Any other ideas?
 
Have you verified the two proms?

Funny you should mention that. After swapping out the SLAGS seemed to have no effect, I started swapping out the other none ROM chips one by one with ones from a known working board. Turns out the majority of the graphical issues were solved replacing the PROM at A5. There are still some glitches around the car that I need to figure out. Ill post another pic in a bit.
I also need to figure out how to get a replacement PROM. The manual says its a 74S473. I don't have one of those chips and I don't think my GQ-4X would burn one anyway.
 
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Funny you should mention that. After swapping out the SLAGS seemed to have no effect, I started swapping out the other none ROM chips one by one with ones from a known working board. Turns out the majority of the graphical issues were solved replacing the PROM at A5. There are still some glitches around the car that I need to figure out. Ill post another pic in a bit.
I also need to figure out how to get a replacement PROM. The manual says its a 74S473. I don't have one of those chips and I don't think my GQ-4X would burn one anyway.


I can take care of burning one of those for you. PM me your mailing info and I'll get it burned and out to you on Monday. I'm out of town right now with a family matter.
 
I can take care of burning one of those for you. PM me your mailing info and I'll get it burned and out to you on Monday. I'm out of town right now with a family matter.

That is very kind and generous of you. I will PM you and we can work it out.
 
Im currently having the same issue. I have the exact thing going on as the guy who started this thread. I have no idea which chip the SLAGS are....and PROM A5...can someone give me a hand? I take it the chips are marked?
 
Get out your manual. It's in the schematic.

If you don't have a manual, check around here - you'll probably find one, or find one online.
 

Gee, I don't get why people feel the need to put watermarks on scans, especially on schematics, that is just stupid.
You can get a better scan here: https://www.arcade-museum.com/manuals-videogames/R/Road Blasters Schematic Package.pdf

Or look here, the PROMS are the two green ones, and the Slags are the four chips marked 137-415, below the left Prom:

roadblasters_seite_621vcco.jpg
 
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And since the above picture is very nice and clear - note the numbers and letters.

The SLAGs would be at B5, D5, F5 and H5 on that diagram.

Vendors like Atari did that to make finding components somewhat easier.
 
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