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Lockup with the flipper is often a 5v / 12v problem. Check 5v voltage at mpu and driver board using the 100uf cap leads as a probe place and compare to the power board. If you are seeing a decent voltage drop compared to the power board connectors are suspect.
The square ac in plugs on the power board can burn up too.
Gentle flex on the mpu and driver board and chip sockets to see if it locks up good test for flaky connection.
Quoted from sharkey1331:Ok... it was not the blanking connector. (Who’s not surprised!?) But, I did fix the game. Here’s what I did:
I replaced the rom and cpu “scanbe” sockets with high quality pin style connectors. Then after trying the game again with no luck (and by now no amount of flexing connectors would get it going again), I broke out the logic probe. Cpu reset, power, ground, and clock all good, but NO activity on data or address lines- the CPU was not running. I burned an “Andre v2.0” test rom on a 2716- plugged it in, removed the other roms and all connectors but the power connector to the MPU board, left the driver board connected to the MPU but removed all of its connectors, and powered up. The test led sequence showed a bad 6810 RAM at chip 16.
Chip 16 was unsoldered, socketed, and another 6810 plugged in. Then I replaced the 40 pin interconnect sockets on the driver board. Retest showed no more issues, so the game roms went back in. All connectors plugged in, power on, and game is up like normal! Hurray!!!
Resolder of the top right mpu header pins, and then an open resistor replaced on the master display board fixed the displays. The game is finally 100%! The Andre rom worked awesome, and I like the PIA test it has as well. Now that it’s all done, I must admit- the game built-in mpu diagnostic feature suggested the ram chip 16 was bad too, So if the CPU at least can boot, the built-in diagnostics are not useless after all…. I think both the standard diagnostics and the Andre rom both pointing at this ram chip gave me high confidence that this chip indeed was bad.
One more thing: I thought the 40 pin interconnect sockets would be a nightmare, and I cut one of the five sockets to make removing the plastic housing easier so I could just worry about unsoldering individual pins. However, what was much easier was the standard: add fresh solder, then desolder, then use hot air to make removal of each housing a piece of cake. This method even left the holes mostly clear, and was fast too.
Anyways, I hope me and sharing this info might help someone else down the road – and I’m grateful for those who chimed in with suggestions! Ultimately, this issue tracked my lazy butt into replacing the interconnect, all the power supply caps and diodes, and the mpu scanbe sockets. The game should be much more stable from all of this.
Nice!
The built in tests in the actual game ROMs are pretty good. They get poo poo'd on a lot but I have found them to be quite reliable as long as the MPU somewhat boots up.
I think people get confused when the CPU is totally locked up and there is erroneous LED activity. It get interpreted wrong and a bad reputation. Leon's memory test was saddly not reliable. I think it gave a lot of false positives if I remember right. Andre's test ROM was always good to me but things have evolved a bit in the 7 years since I made that video. Damn my bench was a mess.
One more thing about your fast scrolling audits... Did you remove the battery holder? If so double check the one terminal that goes through ground, I think it is upper right one. If that plated hole gets taken out it disconnects ground from an IC in the diag button circuit. Causes it to scroll audits rapidly like the button is getting mashed repeatedly.
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