Hi everyone
Appreciate some confirmation on my troubleshooting process. I am working on a System 1 - a Count-Down. The MPU board had been destroyed by battery corrosion and would not boot. So, I replaced all of the boards with a Pascal all-in-one. The game now boots and plays normally. When I first started working on the game, I noticed that someone had removed the yellow target bank reset coil. I replaced it, and then I discovered that the coil would lock on. This must be why it was removed in the first place.
So, as I have a new Pascal board, I do not suspect the board is a problem. The coil and coil diode are also new. So, what is left in the circuit? After looking at Clay's guide I realised that this coil is driven by a 2N5875 transistor under the playfield. It tested good, however I did not remove it from the circuit, so it could be an inaccurate test.
Am I right in thinking that the transistor under the playfield is what is causing the coil to lock on? As far as I can tell there is nothing else in the coil's path. If I am correct so far, what is the best replacement transistor? Another 2N5875, or is there a better replacement part?
Thanks for any advice
