GI blowing fuse on Frankenstein

[Shaven Wookiee]

Hi all,



I have recently picked up a Frankenstein and the playfield GI is not working.

If I replace the F1 fuse, it will appear, really briefly, before fading away and burning the fuse. Has anyone got any ideas? The backbox GI is working fine.



I am putting an order in with Andy soon and was wondering if I should be adding any specific components to the list?



Thanks!



Andy

 

[highjon]

I would think that maybe a lamp holder is shorting out. Check for any that feel shaky or slack, take the lamp out and test across the holder for open circuit.

Hope this helps

 

[Shaven Wookiee]

Hi Jon,



Thanks for the suggestion, I will try it later in the week when I can get the glass off. I have a multimeter armed and ready to use, but would you mind explaining what testing for an open circuit is and what it shows, i.e, good/bad? I have owned pinballs for years and have a decent collection, but my electronic skills are still pitiful (but I'm learning!!!)



Thanks, Andy

 

[highjon]

I would unplug the plugs which does your playfield GI from the main board. I dont have a Sega at the moment so can't say which one it is for definate. Maybe someone can verify, or if you have a manual it will show you there.

Turn it on with these plugs out, if it doesnt blow the fuse then you have confirmed that the problem is on the playfield.

Every lamp (bulb) holder should have no electrical contact between the outer case and the inner conductor ( with the lamp/bulb out and plug out).

Your meter will have a "beep" setting - which beeps when you touch both your probes together. The setting to test a fuse.



A lamp holder shouldnt beep. ie if it does then there is a short / touching across the lamp holder. This can give you the blown fuse F1.

It may be other things, two wires shorting - check no wires have been snagged / crushed when raising/lowering the playfield, or check no lamp holders are physically touching any coils.



hope this helps a bit

John

 

[Shaven Wookiee]

Hi John

Thanks for the detailed advice. I will certainly give this at the weekend.

Andy

 

[pinballmania]

I would unplug the plugs which does your playfield GI from the main board. I dont have a Sega at the moment so can't say which one it is for definate. Maybe someone can verify, or if you have a manual it will show you there.

Turn it on with these plugs out, if it doesnt blow the fuse then you have confirmed that the problem is on the playfield.

Every lamp (bulb) holder should have no electrical contact between the outer case and the inner conductor ( with the lamp/bulb out and plug out).

Your meter will have a "beep" setting - which beeps when you touch both your probes together. The setting to test a fuse.



A lamp holder shouldnt beep. ie if it does then there is a short / touching across the lamp holder. This can give you the blown fuse F1.

It may be other things, two wires shorting - check no wires have been snagged / crushed when raising/lowering the playfield, or check no lamp holders are physically touching any coils.



hope this helps a bit

John

Unfortunately the meter will beep anyway unless you remove every bulb in the chain of paralleled bulbs. You need to establish which chain is the problem and then inspect every lamp holder for potential shorts. If not apparent, then break the lamp chain down into sections, by desoldering wires appropriately, and when you identify the dodgy section, break that down into smaller sections. Its also possible that a blown bulb can itself cause a dead short.

 

[Shaven Wookiee]

Whoops, just seen this reply, thanks for the extra info - I have still not sorted it, but this is because the garage is awaiting insulating and the pin is in a position where I cannot lift the glass. Looking forward to getting it sorted.

 

[Thory]

I have a similar issue, where the upper playfield GI has gone. Checked the F1 fuse and it had blown. Replaced with a new one and the upper playfield GI is still not working, but the fuse has not blown again. Should I desolder where the two wires power each lighting chain on the underside of the playfield and then join the wires together to check which chain is faulty? Or could it be something else for my issue? Thanks for the help.

 

[pinballmania]

That could help. Look for burnt connectors and wires that may have pulled out of them.

 

[Thory]

Found a bulb that was crushed and removed that. It was on a different circuit, but the GI came back to life Cheers for the help.

 

[replicas]

Glad to know you got it sorted.