I have my High Speed working almost 100%. I have a few things going on that I assume are related, but not sure. When I power on the game, I get 5 tones, and then the 1 beep of the system boot. I also get Adjustment Failure on the display. I get a code 0 on the CPU test indicating everything checks out. I de soldered the battery holder a while ago and just installed a remote battery holder. I have verified 4.9 V at the battery positions on the MPU and 4.8V at the last pin of U24 (with the game on, though). Gone through the adjustment procedure a few times to set the game to free play and it accepts free play, but when the power is cycled, I get Adjustment Failure again and free play setting is lost. Any thoughts as to what to try next?

I have been enjoying my HS project for a while now. Since it is working, I have been playing it while I take care of other things. A little while ago the pop bumpers and slingshots died. The problem was intermittent for a few days, but now they are just not working at all. I know they are all controlled via the special solenoid section of the driver board. I did a quick check of the transistors with the playfield connectors off and the transistors appear to be OK. My Pinside and Google search is leaning towards the 7402 IC at U50. I don't want to just replace the part and see if that works. Is there a way I can verify the issue? Using the DMM in diode mode (with the parts connected to the board, but the playfield connectors removed) All of the driver transistors give me 0.6 0.0 and 0.7 from left to right with the black lead on the transistor tab and the read lead going left to right. I also have a logic probe and all the transistor leads have the same reading. Since all the bumpers and both slingshots are out, I would not expect a single transitor failure to be the cause.

I should also mention that the coils fire in coild test, but the switches to no register in switch levels.

Can any one suggest a systematic method of testing for the fault? Special solenoid failures seem to be common based on my search, but I am not finding a good troubleshooting guide.

Thanks!

Thanks Grumpy. Here is the power supply layout. I see Solenoid ground is the bottom part of 3J4, all black wires. It is in the lower left. Is this what you mean? Does this ground apply to all solenoids, including special solenoids?

HS Power Board (resized).png

Grumpy,
Thanks! That was it. The white wire and the one next to it had obvious cold solder joints. A quick reflow and things are back to working!!!!