Crystal Castles Board Repair Log

Found some free to time to dig through a box of Crystal Castles boards we accumulated over the years. Most of these were straightforward repairs, but I'm not complaining, here you go:

Boots, coins up but Start Buttons don’t respond (12/17/19)

1. Inputs at buffer chip at 11C seemed to be behaving normally.
2. Swapped Pokey chip at 3D to fix the problem.

White Screen, Swirl sound on boot (12/17/19)

1. Board sounded close to working, had a white screen like other boards on boot and the swirl sound at boot, but stopped there.
2. Quick inspection show rom at 1N was a revision 205 rom, other roms were 300 series revisions. Installed 305 Rom at 1N and board booted properly.

Garbage on Screen (12/17/19)

1. Board was beeping on booted, beeps indicated bad ram at 4E.
2. Replaced 4416 at 4E to fix the board.

Dead, Reset Low (12/12/19) –

1. Poked around reset circuit, noticed Q2, 2N3904 transistor tested differently than a known working board. 
2. Replaced, Q2, reset line now high, board still not working.
3. Swapped 6502A, board booted up.  Reinstalled original 6502A, board also worked. Reseating 6502A fixed problem.

Watchdogging, Garbage on Screen (12/12/19)

1. Swapped 6502A with known good processor. Board works!