I recently finished restoring my Flash Gordon, however when the machine boots it blows the coil fuse located on the bottom of the playfield. It is a 1 amp SB fuse.

When I trouble shoot it I trace the short back to the Q5 transistor on the driver board. This has happened twice. It appears something is causing the transistor to blow and as a result, the fuse on the playfield blows. I replaced the resistors and diode that feed Q5 (they did test good) and I even replace the diode on the playfield coil that is driven by Q5 (it tested good as well) .

I'm afraid to test it again as replacing the transistor is getting old. I checked all of the other playfield coils and they show reasonable resistance. There does not appear to be any shorts on the playfield. Any suggestions on what else to check at this point??

1) Lower leg of diode CR5 .43
2) Upper leg of diode CR5 .47
3) Pin 14 of U1 .47
4) Pin 13 of U1 .84
5) Pin 3 of U2 3.27

None of the transistors blow, as long as the playfield fuse is removed. Even when all of the connectors are attach to the SDB.

21.4 ohms in each direction with the wires still attached to the lugs. Yellow wire is attached to the banded side.
FYI - if I over fuse the the playfield (3 amp fuse) the fuse on the power module blows. The machine had a 3 amp fuse in this location originally.

IMG_0622 (resized).JPG

Not sure exactly when it blows but it is on startup.

A) 21.6
B) .3
C) 26.3
D) 4.0

Q5 isn't shorted. I checked it, the center tab and neither of the other tabs have continuity. Plus I haven't powered the name up since I replaced it.

Does this seem unusual?

I meant other legs.

Disregard the previous numbers, not sure how I got those. Took these this morning:
A) 21.7k
B) 4000k
C) 21.6k
D) 4000k

I did a playfield swap but didn't re-pin any connectors. I changed the diode on the Q5 coil but haven't powered it up yet. The old diode tested good.

I just swapped in a different driver board from a working machine and although it didn't blow any transistors it appears that the playfield fuse blew again. Start up seemed to work fine, but once I went into test mode none of the playfield solenoids will work.