gwarble
Well-known member
Hey all,
Hoping to dig into this problem a little more so I figured I'd reach out to the experts first...
My Tapper is working well except for one problem its had since I got it... some of the foreground sprites/characters/items are displaying the wrong sprites. Some guys are from the wrong level, sometimes there will be a pair of legs in place of a character...
instead of being left a tip of cash, you're left a cheerleader's arm with pom pom, thats fun...
So reading around the MCR and Tapper books, and some threads on here, seems sprite issues are common but I haven't seen this particular problem. Its not intermittent either, its always the same wrong sprites... So i'm thinking one of the address lines is stuck hi or lo when deciding what sprite to access, maybe some 74LS... chips that control access to the video ram or FG rom...
Anyone have any suggestions on what I should be looking/testing for? Board passes visual inspection, all socketed chips removed, cleaned, reseated... all ROMs on the MCRIII Video Gen board were pulled and verified good, and interconnect cables are new and all headers for them re-soldered.
Thanks in advance
- Joel
Hoping to dig into this problem a little more so I figured I'd reach out to the experts first...
My Tapper is working well except for one problem its had since I got it... some of the foreground sprites/characters/items are displaying the wrong sprites. Some guys are from the wrong level, sometimes there will be a pair of legs in place of a character...
instead of being left a tip of cash, you're left a cheerleader's arm with pom pom, thats fun...
So reading around the MCR and Tapper books, and some threads on here, seems sprite issues are common but I haven't seen this particular problem. Its not intermittent either, its always the same wrong sprites... So i'm thinking one of the address lines is stuck hi or lo when deciding what sprite to access, maybe some 74LS... chips that control access to the video ram or FG rom...
Anyone have any suggestions on what I should be looking/testing for? Board passes visual inspection, all socketed chips removed, cleaned, reseated... all ROMs on the MCRIII Video Gen board were pulled and verified good, and interconnect cables are new and all headers for them re-soldered.
Thanks in advance
- Joel
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