Omega race chip location help

Bearcat93

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Hi,
Still chipping away (pardon the pun) at my OR mini and my beeps in test mode are saying bad chips at 7, 10 & 13. Where are those chips? I looked through the manual/schematics, but couldn't make sense of how to determine where the chips are that need replacing.

Thanks in advance!

Jeff
 
From the manual (http://www.gauck.com/arcade/OR/OmegaRace.pdf) in the section about self-test (page 19-) the chart indicates that a series of 7 beeps points to the chip P3 and/or P/R2. That's because it's the seventh item in the list. It specifies a pair of chips because for the addresses in that range, Omega Race uses one chip for the lower 4 bits of data and the other for the upper four bits.



Next, 10 beeps means VRAM 2 at J1 and/or L/M1 with the same rationale, so it could be either or both chips.



Lastly, the 13 beeps means something is wrong with the VROM E1.



Bad RAM chips are not uncommon and a bad ROM chip is not impossible either. But even if your board has little to no damage from the leaking battery (which should be removed if it hasn't been already) the sockets on these boards are not the best. So it could be either. All are socketed, so you could pull the chips and clean the legs. For the RAM you could swap one of the suspected chips in each pair with one in a location that is passing self-test, and see if the beeps change. That can be confusing to keep track of but without a RAM tester or tube of new chips you can narrow it down.

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Thanks, Doug - you worked on this board at one time! I had it working for a little while, but alas, here we are. Do I purchase the same chip for RAM replacements and another for ROM replacements? I picked up 2114 RAM on someone's recommendation. Do you happen to know if that's right and / or what the ROM type might be?

Thanks!

Jeff
 
Thanks, Doug - you worked on this board at one time! I had it working for a little while, but alas, here we are. Do I purchase the same chip for RAM replacements and another for ROM replacements? I picked up 2114 RAM on someone's recommendation. Do you happen to know if that's right and / or what the ROM type might be?

Thanks!

Jeff

The 2114 is right for any of the 14 RAM chips. The ROM chip at E1 is a 2716 and would need to be programmed with the appropriate code.

When I repaired the board did you opt for me to replace the sockets or did I just fix what was broken?
 
Then it could be sockets. I'd pull out those five suspect chips and maybe wipe their legs with DeOxit or just put them back in and see if reseating them helps (or at least changes your beep sequence). Next would be to swap the pair at P3 and P/R2 with the neighboring pair at R3 and R/S2 and retest. If the beep changes from 7 to 6, it's one of those RAM chips: swap one of them back and if it changes again it's the one you moved; if not it's the one you left. If the beep never changes from 7, it's probably one of those sockets.

For the errors in row one, pull the two suspect RAM chips and see if the ROM error goes away. Those RAMs are on the same (vector) bus as the two vector ROMs E1 and F1, and a bad RAM could mess up access. You'll still get beep 10 because the two chips are missing, but if beep 13 clears up then one of those RAM chips are bad: put them back in one at a time to see which one is blocking access to E1.
 
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