| Arcade Collecting > Restorations & repair |
| Macross PCB No Audio & CMOS Error ***Error Solved*** |
| << < (6/7) > >> |
| Falken Hawke:
Well then... 74LS32 did not effect change... At this point, I moved to the U14 6116 which I avoided since I don't have a means to test them. All I could do was piggy-back another one on it assuming a dead I/O would then go to the chip on top. Unfortunately, this created more screen errors. Following the traces from that 6116, I was led to U15, another 6116. I piggy-backed that IC and this returned a complete test pattern screen 😁 I removed the U15 6116 and installed a socket. Then I fired up the board sans U15 and got "RAM CHECK OK"! Plugged in a new MB8416A (6116 compatible) from "Arcade Parts and Repair" and started up Macross again. |
| bobbyb13:
Yeehaw!!! |
| nitrogen_widget:
Fantastic. |
| Falken Hawke:
Just adding some hindsight items... Shown below are the Pattern and Color Bars test screens generated by the Macross board. Following them are the logic waveforms of the U15 6116 I/O ports for their respective screens. I would assume that the waveforms would be stable as the screens are static. Scanning three times on each screen verified this. ...continues... |
| Falken Hawke:
Going back to the bad RAM IC, while I would only be able to see each I/O had activity if I did not know what a good waveform looked like, scanning the IC while on the test screens three times made the issue with the IC obvious, as shown by these six waveform scans. I hope that helps someone at some point :D |
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