Question (or observation) #2:
Earlier in this thread I made a post about my new JP I am fixing. MAIN pain in the ass is the raptor kickback blowing transistors. From the start the raptor coil had melted, and Q4 was dead, Q30 tested fine on the board.A short summary:
1. We soldered on a brand new coil coming with a diode on, soldered the wires on the correct side.
2. Soldered on a new Q4. Started the game, the coil locked on some seconds then retracted the plunger, as if on test. It smelled as if something burnt, but the coil was fine.
3. Q4 was dead again. But since the coil did not lock (ie not burning)on when starting the game again, we played for maybe 15 mins just checking how the game felt without the kickback.
4. When I started going over the game again yesterday, some weeks later,I was going to fix other stuff and do the raptor later since it didnt hurt playing without it for now. But I opened the backbox to find the ppb like this (see attached pictures). The R16 completely burnt and melted, leaving an ugly black trail up to the fuse F5,but it seems mostly cosmetical. Q4 looked as it had burnt even more, though being dead.
On further inspection, and a big note to self, "check all fuses". F6 (for the raptor/50V coils) had 5A, should be 4A. F7 and F9 had...wait for it 12A and 13A, should be 3A and 4A (if i remember correct). Fixed the fuses.
Can anyone explain or have theory on how the dead Q4 can continue burning and melting the R16 also, when the coil still is fine and not melted/melting? Can the F6 fuse that had 5A be so strong compared to 4A that it did not break when it should, and therefore allowing the voltage to continue grinding onto Q4 and R16?
Todo: If the ppb can be saved, have someone solder on the dead components (R16,D18,Q4) and also a new Q30 on the cpu board even though it tests fine. New fuses are correct rating, and the coil/diode seems fine. The J7 connector has no burn marks. Have to trace the cables all the way. If it after all this is done still not work...new rottendog board....:/
PPB closer toast.JPG
PPB back toast.JPG