Sega Star Wars Trilogy Coil Tomfoolery

[Andy B]

Working on a Sega Star Wars Trilogy for a friend.

Bottom VUK coil locks on at boot up and blows 50v fuse (F21).

MOFSET (Q6) that controls that coil is missing completely from I/O board. Wire from resistor for that MOFSET (R6) has been soldered to point where resistor R8 should be (missing) which is for MOFSET (Q8) for an optional European Ticket Dispenser (not fitted).

Control wire for the Bottom VUK coil (BRN/BLU) which should be on pin 7 is actually on pin 9 of connector J8 (which is the pin supposed to be feeding Q8 ticket dispenser).

So, I’m guessing that whoever’s been working on it previously has got fed up of replacing Q6 or has replaced it that many times he’s buggered up the solder holes on Q6 so instead has diverted path from R6 to R8 which leads to Q8 and used the MOFSET intended for the optional ticket dispenser for the VUK instead.

Does that make sense and if it does is it a big issue. i.e. any reason I can’t stick with this hack and replace Q8 (which should be Q6 ) as long as I make a note of it for the next person who needs to fix it should my mate ever move it on?

Photo below.

Thanks

Andy

 

[Andy B]

 

[strobey]

Think your dead right there, seen that trick used before on the previous gen PPB boards.

Decisions aside, you've gotta ask yourself why the VUK keeps blowing the tranny. I'd check that the diode is in place between the coil lugs and get that replaced first even if it looks good.

Classic board wrecker when they go bad or dry jointed..

 

[Andy B]

Cheers strobey - I’m not going loopy then!

Diode will deffo be replaced.

 

[CHRIS B PINBALLS]

It’s probably not been replaced that many times they are not that easy to get out on those boards as it’s sort of hooked in at the back
There are no pads left on it so fitting another will only look like a pigs ear if it was me I would just replace the vuk coil and the other mos fet and just keep that jumper on it or do it from the rear of the board if you hate looking at it

 

[Andy B]

Cheers Chris. Makes sense. My desoldering and component removal skills are not that hot so hopefully I won’t rip the pads off when I swap out Q8!