Blown fuse

[piesrule]

Wondering if anyone can help? I blew a fuse (F112) on the main board in my TOM, so no problem, i'll just buy a new one and change it which I did although it blew again straight away so obviously there is another problem. Can anyone tell what part that circuit that is protecting as I have some idea were to start looking. Thanks in advance.

[MartyJ]

Had anything happened prior?

Fuse F112 is for the solenoid secondary and should be a 7amp S/B

Is the fuse blowing immediately on power up?

[piesrule]

yes it was working fine prior, is was a 7amp fuse I used although not sure if it was a S/B (would that matter) It blew the second I turned it on.

[Homepin]

The fuse is ONLY there to stop your house from burning down when there is a fault. The fuse is NOT there to protect your machne from a fault.

Seems you have a shorted transistor etc etc etc that is placing a large load on the circuit that the fuse is designed to protect.

Remember that when the machine is sitting in game over mode 70VDC is still applied to all the coils and the driver output circuits so a problem could occur at any time when you are not looking.

I would start by studying the circuit and fully understanding exactly what is connected after that fuse - then isolate the connected circuits until you locate the culprit.

[piesrule]

 Would that mean the problem is in the main board? if so I would be better of removing the board and have someone test it, the last game I was playing I left it in between balls for about 20mins, when someone came to the door, could that of caused it?

[pinsanity]

My bet is it will be a shorted/failed BR3 (bridge rectifier) on the main board in the backbox.

Can you tell me if Fuses 101-105 are blown and that they are the correct values?

[Marty Machine]

IF the power-supply board (with fuses) is on it's own, then pull out ALL cabling that go out to other boards...just leave the 240v mains into the power supply, then turn on the power and see if fuse blows again.
If it blows, something on your power board is shorting, more than likely a bad bridge-rectifier as suggested.
If your fuse doesn't blow, then it's definately an external board/loom/solenoid causing the problem.
(plug in cable/connectors 1-at-a-time onto the power board, to see WHICH board is causing the problem).

IF the power is part of a main driver board, at least remove all cabling that go from the driver/power board to other boards, and confirm if fuse blows (or not) again.
At least the fault will be on that board, or not...


Elimination......

[beaky]

My bet is it will be a shorted/failed BR3 (bridge rectifier) on the main board in the backbox.

Can you tell me if Fuses 101-105 are blown and that they are the correct values?

+1
if all the other fuses are the correct value then my guess is the bridge has failed

[piesrule]

My bet is it will be a shorted/failed BR3 (bridge rectifier) on the main board in the backbox.

Can you tell me if Fuses 101-105 are blown and that they are the correct values?

All the fuses you mentioned 101-105 are correct values and ok

[pinsanity]

My bet is it will be a shorted/failed BR3 (bridge rectifier) on the main board in the backbox.

Can you tell me if Fuses 101-105 are blown and that they are the correct values?

All the fuses you mentioned 101-105 are correct values and ok

Test the BR3 legs with a DMM for correct readings.

How to here:
http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Failed_Bridge_Rectifier

[piesrule]

Thanks guys for all your advice although all the electronic stuff is over my head , so i'am wondering if there is anyone in the eastern suburbs of Melbourne that has the equipment and the knowledge required and wants a paying job? About the best I can do is locate the bridge thingy which i was able to find in the top left hand corner of the main board and that's the extent of my expertise.