williams system 7 help

a_wookie

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I have a issue with my solar fire, when you start up a second player the start button also presses a tilt switch.(not sure witch one)

also when you start a single player game it also gives you a random score between 2,000 and 8,000 depending on how long you press the start button.(if you tap the start button quickly you get no points awarded)

I have already isolated the slam and normal tilt from the system but still this closure persists.

After studying and looking over the schematics package i think that the problem is with one of my N4706 IC's in my column drive. the N4706 is a hex buffer. and the ones i am questioning are IC17 and IC18 on the schematics.


any thoughts from you guys before i just shotgun both the N4706's in the drive??
your thoughts are greatly appreciated

thanks in advance
 
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It's not slam-tilting..... that totally resets the machine.

I'd start with taking all the balls out, making sure all the drop targets are up, and going into switch test mode. Figure out which switches are being triggered when you hit the credit button.

I'm going to say you probably have an issue in the wiring for Row 3 somewhere.

-Hans
 
It's not slam-tilting..... that totally resets the machine.

I'd start with taking all the balls out, making sure all the drop targets are up, and going into switch test mode. Figure out which switches are being triggered when you hit the credit button.

I'm going to say you probably have an issue in the wiring for Row 3 somewhere.

-Hans

thanks first off, i did as you suggested, and sure enough row 3 is the problem.
when i hold the credit switch the entire row is displayed as a stuck switch.
if i press and hold any of the other switches in row 3, say switch 27 only that switch is displayed not the entire row.

I cut the playfield tilt out of the circuit and it still closes the PF tilt so I assume it is a on board issue?
is it IC 15, the resistors/cap for row 3 or what.

Thanks Hans
 
More often than not, it's a problem with something shorting/grounding in the wirng harness, or possibly a bad diode.

Is it only the credit switch that causes that? I'd take a close look at it to see if it's grounding against anything in the cabinet, or if the wiring's been altered at all. Maybe replace the diode if there's nothing visibly wrong. Those 1N4004's are dirt cheap via e-bay, and it's good to keep a few on-hand anyway. That part number is on all the switches, lamps and coils.

-Hans
 
More often than not, it's a problem with something shorting/grounding in the wirng harness, or possibly a bad diode.

Is it only the credit switch that causes that? I'd take a close look at it to see if it's grounding against anything in the cabinet, or if the wiring's been altered at all. Maybe replace the diode if there's nothing visibly wrong. Those 1N4004's are dirt cheap via e-bay, and it's good to keep a few on-hand anyway. That part number is on all the switches, lamps and coils.

-Hans

thanks Hans,
i had some 4004's here already, i replaced it and nothing changed i also noticed other row closures on the ball tilt, slam tilt and regualr tilt besides the start button closures.

i was going over switches looking for shorts and noticed credit switch 2 had
been stuck closed and it looked like the diode lead was touching the door.(machine in free play)

i corrected this and restarted the system, now i have no ghost closures.
might have been the diode at the start button still.... im not sure, but its working now.
and thats what counts....


thanks to Hans.
 
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