Leaderboard

Hello. My studs are made of metal; what a shame. They'll stay that way; they're well insulated now. Yes, the push-button switch isn't stuck; that's the first thing I checked. I'll double-check this whole area before replacing IC4. As Bob said, it's not easy to do inside the cabinet. jjmXXX; it's a normally closed (NC) contact; if I disconnect a wire, it's the opposite. Thank you for following this adventure.

Does it still do it if you disconnect a wire from the back of the switch?

Those studs are made of plastic (or they should be) so they won't need insulating? The only metal ones are the two fixing the board to the chassis and two holding the ROM cart holder. Before replacing IC4 I would check if any other switches on the same line are working. I would also find out exactly which one it's on (9 or 10) then see what switch it is on the black connector and also the DIL switches. If you can find what they do it will be easy to check that IC4 is OK. You could put the scope on it and see if there's a waveform going in to IC22. With no switches operated there shouldn't be. Are you sure the switch isn't stuck on?

More to come, if you don't mind... My display was completely malfunctioning. But after cleaning and lubricating all the connectors, it's back to normal. (I used brake cleaner and a very small amount of silicone lubricant.) It's probably also because I properly insulated the PCB's mounting points. This prevents short circuits. As you can see in the photos, I used two layers of heat-shrink tubing. I had already done this on the first MPU, but on this one, I had to double it up. Overall, it works; the hold function and sound are still an issue. Plus a few other minor things here and there. Thanks Have a good weekend. Sorry, I can't seem to reduce the video size. Afficheur qui délire.mp4