Trying to troubleshoot a friend's pin. I reseated all connectors to PCB boards in the head, check the Buss fuses there as well and visually they look good. (reseated as well). Machine powers on, have lights and some sign of life on the score displays, absolutely nothing on playfield and won't start a game. Checked all tilt switches as well, nothing contacting.

Tim

Thanks. He's owned the game for quite some time. It was working about two weeks ago, fired up recently to these symptoms. So there's all lights on backbox, the score displays show some lines and a dot, but I believe he's always had it show that way (other possible issues there). There's simply no life (no lights, can't start game, on playfield). I agree, I'll check the fuses better than just visually, as it seems like there's simply no power going to the playfield at this point.

Tim

Apparently can't edit my title to fix it to Williams. (although thought the Nitro Groundshaker tagged, listed as Bally, was the machine in question) Not sure why I had Bally on my mind. Going to be awhile to get pics, there's not much to show, backbox fully lit up and powered and the score displays as mentioned (although this symptom exited earlier I believe) no numbers, just some lines and a dot.

The playfield has no power at all. That's it. Boards in backbox, reseated/checked all harness/connections, only a green solid LED on one main board, reseated fuses (but as previously suggested, could still be bad but not showing visual issue). Basically no power/life to playfield.

Tim

Fixed title, I was getting the Groundshaker/Earthshaker confused in way of names.

Tim

Ok, was finally able to see the machine again. MPU honestly doesn't seem to have batteries at all, I'd expect to see AA batteries? The LED on the MPU is indicating an error (not sure fully what) flashes a single time, with a short delay, then two more and then goes solid green. So three flashes? The power supply board however, there appears to be someone's previous repair job on it in the lower left, one of the mosfet appears replaced and the traces on the back near it must have been damaged and pulled up. They jumpered a wire across (possible ground) to have continuity going across. There's a resistor above this one that behind it on the PCB board is burnt/something had caught on fire at some point. But the resistor doesn't look burnt, and hard to determine if previous repair person may have replaced this resistor. The burn on the board originates from the mosfet, but the current one appears to be original to the rest.

I've brought the power board home to try to clean up this butcher repair job and test the resistor/mosfet. I checked all fuses and they check out, are passing current. After reseating these again after testing, there was one single light on the playfield showing lit, which it wasn't before, but still everything else on playfield dead/no power or life showing.

Tim

Thanks! So with other reading on this, is the initial flash a "flicker", followed by two flashes? Reading on U10 thread where they reference getting flashes after an initial flicker. Going to see what I can do with fixing up the bad repair jobs first, and I'll have to get my hands on the MPU as well if U10

Tim

Thanks! Yes, if I counted correctly, first initial flash, two blinks of light, then solid green on third one. So U8/5101 should be the case. Wish the machine wasn't an hour drive to get back to it to do further work. I had taken the power supply board home to go over, and as messy as the previous repairs look, it seems to have continuity through the area fine and components appear fine.

Back to MPU then, if LED status correct, I'll get pics of the areas requested, and will watch the LED startup again to verify it is locking on 3rd.

Tim

Yes, as mentioned, there's a brief flicker on start, then I count at least two solid flashes, then stops on a solid and kept on green.

Last time I was at the machine, one single light on the playfield was lit when machine powered on. It wasn't like that before. Still no life then, doesn't coin up, doesn't start game. Just the full backbox lit, and now a single light on playfield.

Tim

Thanks for all the help. So it was stopping after third light, so U10 or U11. Popped out U11 IC first and it looked fine. U10 a different story, darkened pins and very brittle pins, two were broken off in the socket and I suspect at some point making enough contact for the game to work, but changes in temperature or board flexing caused it to stop. Going to order a replacement IC and replace the socket.

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Replaced the socket for U10, ordered/replaced the IC, get 2 LED flashes and stops (no stop on green for third, I may have been mistaken on that last time). So now it looks like U8, the 5101 RAM/socket. The MPU has the original circular battery on board, now that I know what this looks like. Am either replacing socket and 5101 RAM for U8 and cross fingers, or buy/find a fully working MPU and swap the whole thing.

Damn socket for U10, these boards were made horrible, traces lifting with desoldering, never seen a board have traces just pop off so easily. (having hardened a Galaga main and video board, about 40 sockets and never a trace come up)

Tim

So finally got further on this. Friend didn't order the 5101 NVRAM that may have fixed the MPU, I had him obtain one of the universal Marco boards, swapped it in yesterday. Playfield now works, all lights/targets. However, not a single solenoid (ball kick out, flippers) do not work. They worked before old MPU failed. Seems like low power however, flippers make a light buzzing noise and move a hair. So maybe solenoid driver board now? Original solenoid board has some old repairs on it, and am thinking of just finding/getting a replacement. But wondering if anyone may have encountered similar when using a modern MPU?

I may suggest he gets this now too: https://www.marcospecialties.com/pinball-parts/ULTSDB

Tim