Pinball Magic Blowing Fuse F9

[MajesticPinball]

Evening everyone, my Capcom PM has started blowing the fuse at F9 on the power board which is a T4A fuse. This fuse powers the magic wand magnets. Currently the wand coils will magnetise and levitate 2 or 3 balls and then the fuse pops. If anyone has any ideas what could be the issue i would really appreciate it. Ive checked the coils and they seem fine and from what i can tell the transistor driving the coils is fine as well, could it just be the diodes accross the two coils in the wand causing this?

Thanks,
James

 

[DRD]

Hi. I have zero knowledge on Capcom games. Might it be a faulty bridge rectifier ? My FT began blowing fuses and this was the cause

 

[MajesticPinball]

I would usually dive straight in and test my way around the boards but I’m hesitant with the Capcom as i also dont know much about them either. When it arrived it was in gorgeous condition so I’ve just been enjoying playing it rather than tinkering with it.

 

[Moonraker]

Change the drive transistor first, it might be failing under load... Should the problem continue then I'd look for a short on one of the coils.

 

[MajesticPinball]

Ive just placed an order for a few transistors, hopefully thats the issue. Will report back soon with a working machine hoepfully!

 

[MajesticPinball]

Replced the transistor and the fuse still blows while carrying the ball down the wand. Retested the coils and theyre both coming out at 12ohms. Then i tested each diode across both of the coils with one leg out of circuit and one is testing at 690 and the other at 710. I reverse the DMM leads and both diodes read 1. Im using a super cheap backup multimeter at the moment so im unsure about the readings.

Whats your thoughts?

 

[Moonraker]

first thought... did you replace the correct transistor..? ! !

Check ramp/magnet enter switch is not stuck on.

You could try swapping the coils over with others in the game to see if the fault moves with it. Make sure the coils match like for like.

 

[MajesticPinball]

Yes the transistor which runs the wand magets is S20, have an evening free tomorrow so will try and hunt down the problem

 

[DRD]

Have you checked the voltages on the various touching points?

If you don't have a transistor lock on, and the coil is ok, doesn't that mean it is getting too high a voltage from somewhere?

 

[Moonraker]

It's normally the opposite, power is there all the time, the transistor operates providing a path to earth which completes the circuit operating the coil.

 

[MajesticPinball]

@Moonraker Thats what i thought but i will check voltages on the boards as well. Annoyingly I dont even know what to suspect at the moment. Me having zero experience with Capcom machines isnt helping either

 

[Moonraker]

Voltages aren't the problem otherwise the coils wouldn't operate...!

 

[MajesticPinball]

Quick update, Ive changed the diodes accross both coils and the wand now works without blowing a fuse. I’m not entirely convinced however as the wand mech is getting really quite warm after a few shots accross the magnetic wand, is this normal? I know that the machine prevents balls going accross the wand after a few consecutive shots to allow it to cool down but i never realised the coils got so warm

 

[Moonraker]

Yes, coils can get very warm. Play for an hour then see how warm your flipper coils are...! That goes for most games, not just PM.

Great news that you've sorted it.

 

[MajesticPinball]

I cant say i had ever really noticed it how warm coils can get but it makes sense. Very happy to have it playing again finally! Thanks for your suggestions everyone!