Pinbot

[I C U]

While replacing the troublesome drop target coil I stupidly let it hang to test it was working..

It didn't work and there was a slight smell of burning (I didn't see where from...) and switched it off immediately.
I did solder the coil correctly.

When switched on all seems to be working except for the drop targets and the two 'finger' flashers on the right side of
the back box.

The relay on the right of the playfield continually clicks as though trying to tell the targets to reset.

Please point me in the right direction as to where to look first... sadly I work on a trial and shocks basis... and
the manual might as well be written in hieroglyphics!!

Many thanks!

 

[Jay Walker]

The target reset coil and the flashbulbs are designated as solenoid 04A & 04C respectively, and share a 'driver' transistor (Q24) on the Cpu board. That's probably what you smelled burning. PinBot doesn't have any unused solenoid drivers, but you could transfer one only used for flashbulbs, such as Q6 or Q8. That's if you're minded to tackle a pcb repair.

Before trying out a repaired board, though, check that the coil is alright. With connector '1J11' of the Cpu board (for eight of the solenoids) dis-connected, power up the game. Obviously those eight solenoids won't work, but use a jumper lead or simply a length of wire to ground the target-reset coil; momentarily connect between the 'tail' end of the coil, where the plain end of the diode is, and the earth braid on the inside of the cabinet. If the fuse & coil are good, it should pull-in and reset the targets. If a short-circuit coil was left in place, it would damage the repaired circuit again. Also check for solder splashes (conductive debris) under the playfield, especially the diode switching pcb, as mentioned below.

Re. the relay clicking. There are a few relays under the playfield, as well as a large pcb containing 16 heavy diodes. Only one of the relays, the 'Solenoid Select' relay, has a bearing on the target reset coil - it switches the drive transistor (and seven others) between the 'A' side (operating the coil), and the 'C' side (lighting the flashbulbs). The reset coil isn't a big enough load to need its own dedicated relay driver stage, unlike some other games, which are full of relay pcb's (F-14, f'r instance, has seven).

 

[I C U]

Many thanks for your detailed reply Jay!!

Tomorrow I will have a go at all your suggestions!!

Thanks again for your help, much appreciated!!

 

[I C U]

Hi Jay,

Like you advised the Q24 has indeed burnt and on doing your 'earthing' test the (brand new) coil did not work.

I replaced the old coil and the test worked so I guess I have also fried the new coil..

When you say I could use Q6 or Q8 do you mean take one out and solder it into the Q24 position or is it something
that can be done via wiring?

Please advise what I should be buying (and where from) to replace the Q24 driver transistor.

Again, many thanks for your help!!

 

[Jay Walker]

Yes, I thought that you could pull out Q6 or Q8 and solder it in place of Q24. Though then the load of the borrowed device wouldn't work; pinching Q8 would disable the General Illumination 'breaker' relay for the playfield, while the better choice might be Q16, which controls the backglass gen. Illumination relay (the G.I lamps simply wouldn't switch Off if you borrowed either of these). The transistor is a 'darlington' type, code number TIP 122. I'd suggest asking Andy at pinball mania to supply one.

 

[I C U]

Part now ordered from Andy... I had better get to work honing my soldering skills.......

Many thanks for all your help Jay!!

Regards
Steve

 

[I C U]

Just to say I have replaced the driver transistor in the Cpu board and all is now working perfectly!

Thanks again for all your help and advice Jay!!

Regards
Steve