Bally Solved Kings of Steel (Bally, 1984) F2 fuse blowing

[kingsofsteel36]

Hi, I'm trying to figure out why the F2 fuse is blowing on the rectifier board (board AS2518-54).
I checked the voltage and they are all in range except for TP1 and TP2, although TP1 is not that far out of range:
TP1 is 7.9 (supposed to be 5.4 +/- .8 )
TP2 is 0 and F2 is blown.
The rest are all in range.

I tried disconnecting the connectors and putting in a new fuse, and it blew again anyway.

I pulled out the board and checked the bridge rectifiers and all seemed to be ok (so I did not replace them). I also checked the diodes and they seemed ok. So, I'm at a loss as to what could be the problem. Does anyone have any ideas?

Thank you.

 

[Coil_Smoke]

Some times electrolytic capacitors develop internal shorts. Capacitors can be hard to test in circuit. But they should show some sign of charging from the current from your ohm meter. That is the resistance should increase as the probes are held in place.

 

[kingsofsteel36]

Thanks for the reply, Coil_Smoke. I'll recheck them. If I can't tell, I have the parts, so I can also try replacing the capacitors and see what happens.

 

[kingsofsteel36]

Ok, I worked on this some more. Coil_Smoke, I wasn't sure if you meant the varistor or the diodes? I don't see any capacitors there?

I did do some more testing (and blew some more F2 fuses in the process). I tried disconnecting some of the connectors from the rectifier board (board AS2518-54) with the following results:

J5 + J6 + J1 all connected = fuse F2 did not blow
J5 + J6 + J2 all connected = fuse F2 did not blow
J5 + J6 + J3 all connected = fuse F2 did not blow
J5 + J6 + J4 all connected = fuse F2 blew!
J5 + J6 + J1 + J2 + J3 all connected = fuse F2 did not blow

There seems to be another possibly related issue somewhere in the game because with all of the connectors attached (with or without J3) I get lights on the playfield and the back board (not the high voltage numeric displays, which makes sense), but there's a solenoid that seems to be constantly firing when I turn it on.

The game was working for the most part before (one of the solenoids for the drop targets was constantly firing), but then I replaced the original solenoid driver board with the alltek ultimate one. I turned on the machine after replacing the board, and that's how I got to where I am now...I noticed the F2 fuse had blown on the rectifier board. So I'm not sure if the new solenoid driver board is bad or what.

Thanks again for any ideas on this.

 

[kingsofsteel36]

Update: It seems there must be a loose wire in one of the connectors. I tried the old solenoid driver board again and this time the game worked as it had before (everything was working except for the one solenoid that was constantly firing).

After disconnecting and reconnecting the new Alltek solenoid driver board a few times, the game now works perfectly and the fuse doesn't blow.

Thanks for the help.

 

[Coil_Smoke]

Update: It seems there must be a loose wire in one of the connectors. I tried the old solenoid driver board again and this time the game worked as it had before (everything was working except for the one solenoid that was constantly firing).

After disconnecting and reconnecting the new Alltek solenoid driver board a few times, the game now works perfectly and the fuse doesn't blow.

Thanks for the help.

Hey ... That is great news ... C_S