Fuse problem with a 1979 Bally machine

Pinball2002

Inserted Coin
I have a 1979 Lost World machine that just started blowing a fuse. It used to work perfect and then one day I turned it on and the fuse blew. I've replaced the fuse many times but it keeps blowing out. I even tried a fuse that had a higher rating, but that blew out also.

I am pretty mechanically inclined, but I'm a little nervous about jumping right in with electrical issues -- given how old the circuit boards are.

Does anyone have an idea where I should start? What may be the cause?
 

EnduroExpertFSR

Pinball Nudger
well first things first you should NEVER ever replace a blown fuse with a bigger fuse, you may cause damage or fire to the machine. secondly what does the fuse go to? lights, relays? solenoids? that will help narrow down the problem a schematic would make this alot easier. anyways more than likely you probably have something that is causing something to stay "locked on" does the fuse blow instantly? or does it take a few seconds? do you hear a loud buzzing or chattering sound when the machine is on?
 

faralos

Faralos
isit the main power fuse? for one so mechanically inclined NEVER use a larger fuse if there is a problem it may bypass that fuse with too much juice taking out something far more important (i.e. expensive). take a look at the wires going to the power supply (after unplugging it first, please!) look at the power cord itself check for cuts or frays. look at the connection at the Power supply, THEn travel outwards. if it initializes then blows it may be a bad solenoid or a short on one of them. again look for bare wires shorting somewhere. run a multimeter across a connection at its end and beginning check just for continuity (NO POWER used here at all) esp the plug and its end at the PS.
 

Anthias

Pinball Player
hmm... depending which fuse it is there are many possible causes. If its the one alone on the mpu board, it might be a score panel problem - remove each in turn to see which one, and it should be repairable - its just a short or blown component on it. If you replaced that fuse with a higher rated one, then the c23 capacitor next to it hopefully absorbed the juice, else it could be VERY costly. (or it could be that capacitor but usually that will just reset the machine repeatedly without blowing the fuse)

As for the rest of the fuses - if its the one on the playfield, check for a short on the wires from the flipper solonoids, and if its one of the six or eight on the main cluster of fuses, well that gets much more complicated.
 

inkochnito

Instructioncard creator
I have a 1979 Lost World machine that just started blowing a fuse. It used to work perfect and then one day I turned it on and the fuse blew. I've replaced the fuse many times but it keeps blowing out. I even tried a fuse that had a higher rating, but that blew out also.

I am pretty mechanically inclined, but I'm a little nervous about jumping right in with electrical issues -- given how old the circuit boards are.

Does anyone have an idea where I should start? What may be the cause?
Which fuse? (F1 or F10 ect...)
 
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