Member smalltownguy sent me this boardset to see if I could fix it. With all my work and stuff here is an update to the repair. Symptoms board would freeze up and graphic issues plus sound doesn't work.
-Verified all Eproms and all Eproms tested good.
-Replaced 4 2114 ram on CPU board and fixed a few nicked traces.
-Resocketed 8 unknown ram 1 ram was giving a graphics issue after the resocket. Manual calls for 22pin ram 256x1 but the schematics showed different. Found a hoei boardset and found it contained 5101 ram so I replaced the ram with new 5101 and it cleared up the one problem I was having. Note I tried using 93422 ram but that ram did not help it made it worse.
-Replaced 3 74LS174 on V board using comparator these chip tested faulty.
-Rplaced 1 74LS157 on V board using comparator this chip tested faulty.
-Replaced 2 74LS00 on V board using comparator these chips tested faulty.
Board plays fine with no graphic problems and now to tackle the sound board.
On another note in my video I mentioned the LS00 and then I said LS04 this was an error
so don't hold anything against me I was trying it by memory and the older you get your memory goes lol. And the 04 was a hex inverter but I should have said the LS00 was a quad 2 input nand gate.
here is a link to video
http://youtu.be/dpjjNAkz1r8
-Verified all Eproms and all Eproms tested good.
-Replaced 4 2114 ram on CPU board and fixed a few nicked traces.
-Resocketed 8 unknown ram 1 ram was giving a graphics issue after the resocket. Manual calls for 22pin ram 256x1 but the schematics showed different. Found a hoei boardset and found it contained 5101 ram so I replaced the ram with new 5101 and it cleared up the one problem I was having. Note I tried using 93422 ram but that ram did not help it made it worse.
-Replaced 3 74LS174 on V board using comparator these chip tested faulty.
-Rplaced 1 74LS157 on V board using comparator this chip tested faulty.
-Replaced 2 74LS00 on V board using comparator these chips tested faulty.
Board plays fine with no graphic problems and now to tackle the sound board.
On another note in my video I mentioned the LS00 and then I said LS04 this was an error
so don't hold anything against me I was trying it by memory and the older you get your memory goes lol. And the 04 was a hex inverter but I should have said the LS00 was a quad 2 input nand gate.
here is a link to video
http://youtu.be/dpjjNAkz1r8
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