| Arcade Collecting > Restorations & repair |
| NPs Paperboy Restoration |
| << < (6/11) > >> |
| Neverending Project:
--- Quote from: Neverending Project on September 16, 2008, 10:53:28 am ---Is it even possible to replace only one ROM chip, assuming I could find a replacement or figure out how to burn a new one? Hmm, come to think of it, how would I find out what would need to be burned on each chip? --- End quote --- Never mind about this one. After thinking about this for a minute (and having a cup of coffee) I realized that I have all the chip/rom information on maws. |
| channelmaniac:
Keep in mind that the MAME dumps aren't always the version of code you have. Use your EPROM programmer to read the ROMs/EPROMs and use ROMIDENT to see if they are good and what version they are. If they show up as unknown then run the checksum ROMIDENT gives you through Google to see if you get a match somewhere else. If all show good and known to ROMIDENT except for 1 or 2 then you know you have 1 or 2 bad ROMs. That's something I always check when repairing game boards. |
| Level42:
Doesn't the test screen indicate any ROM/RAM errors. What brand RAM's are they ? And yes you can always replace individual chips. |
| channelmaniac:
--- Quote from: Level42 on September 19, 2008, 01:32:00 am ---Doesn't the test screen indicate any ROM/RAM errors. What brand RAM's are they ? And yes you can always replace individual chips. --- End quote --- Not always. Test screens indicate RAM / ROM errors but you have to be careful in that most games won't test every single ROM. Some do, many do not. The ones that are usually left out are the video graphic ROMs. |
| Neverending Project:
No luck on finding anything by changing the RAMs around. The test screen does not report any RAM errors, but I went ahead and "rotated" a, existing 6116 chip through each of the other 6116 sockets. The problem is always the same. So I am fairly confident that there is nothing wrong with the RAM chips at this point. My gut feeling is that there is some sort of address bus issue. My second thought is a ROM issue. I can't imagine that one of the ROMs would have gone bad and the game would still play - but I haven't ruled it out. I haven't yet figured out a way to test the address bus, but my theory is that if there is a problem with one channel, all the data being carried over the bus would be scrambled. To test the ROMs I suppose I can get an EPROM programmer. But then again, the test screen should test the ROMs too. I wish I had another Paperboy board to test. At least I could absolutely narrow down the problem to the video or CPU board. I'm always on the lookout, though. As a last resort, Frizzle - if you're reading this, would you test the board out for me in your cabinet if I shipped it to you? |
| Navigation |
| Message Index |
| Next page |
| Previous page |