Williams Sys 7 BK - Switches die at random

[Zellcorp]

Hi Ive managed to get my game working, although no one was able to help me with my last problem I'm hoping this one may be more straight forward.

the game seemed to be working fine I played a game for awhile, suddenly the left and right slingshots and the top pop bumper stopped firing, I checked the diagnostics to see if it was a coil issue but all the coils fired fine, I then started a game and pressed all the switches manually but none would fire and the score switches seem dead too only related to those 3 areas left and right slingshot, top pop bumper all other switches in the game seem to be working fine. I took my spare driver board that works fine and tested it in the unit but the same problem was there so seemed like a switch playfield problem

strangely enough I left it for the night then come back to it the next morning to find they had briefly come back alive then suddenly they died again.

sometimes they just seem to come back to life but not for long, I replaced the diodes and caps on the switches but seemed to have no effect.

anyone got any ideas what to look at? should I replace all the playfield diodes?

thx
Z

[Steevsee]

Sound like it could be a short under the playfield.

I'd be checking around the coin switches and those loose wires again.

The loose wires may not be re-connected correctly to "daisy chain" to the next switch.

Run full switch diagnosis to see exactly what is and isn't working.

The switches for the pop bumpers and slings are part of the special solenoid switches and not part of the switch matrix.

Have you seen the repair guides here? (EDIT Link Removed)
And do you have a Manual? http://www.ipdb.org/files/310/Williams_1980_Black_Knight_Operators_Handbook.pdf

[Zellcorp]

lol yes those 2 links are my bible at the moment.

yes I was thinking short too, might review all the switches in the diag like you said cheers.

as far as the extra wires are concerned though im unsure how I would complete the daisy chain as is has its original 20c coin slots but there' no center coin slot as is indicated in the wiring diagram for that color the wire is for (white/blue)

there's 3 wires sticking out, 2 green/brown joined together and white/blue on its own. I think the 2 green wires joined is completing the daisy chain if I believe correctly?

Z

[Zellcorp]

Done my switch review, finding lots of factory defective switches.....looks like I need to replace most of them.

found a defective switch on 16 (inlane) replaced it, now center pop hole switch died, bizzare.

[Steevsee]

I'd say it would be unusual to have more than one or two faulty switches in your game.

If many are not registering in switch test, the problem might still be a short or possibly a connector issue and not the switches themselves.

Also you said the game was working ok before the problem occurred?

I wouldn't replace any more switches just yet, unless you are 100% sure they are faulty.

Do you have a multimeter to test the switches?

[Zellcorp]

Turns out it was the drive board to playfield connector recepticals that were faulty