I can't seem to get rid of switch errors 17, 18, 19 - the 3 ball trough switches. Attract mode but the game doesn't start. Under-playfield looks fine but I'm not certain how to troubleshoot the rest. They all run on the 2J2-7. Perhaps the ICI8 (7406) chip is bad? Any other suggestions?

Thanks for looking. Kev

Check to make sure you have continuity from the switches to the connector at the driver board. You probably have a broken wire in the chain somewhere. Check that first before you start digging in to the board.

Update: If I trigger the Outhole switch (#20) then I can start a game BUT the left target bank (Q17, Q8 ) don't register/work. However, it does fire during the solenoid test.

Almost there ...

I'm no expert, but are those actually 'errors'?  I know with some machines I've had, if you go into test mode, it tells you what switches are activated, not necessarily 'errors.'  With BK, I'm guessing it should list those three switches - you have balls sitting on them so they're activated.
Just a thought, perhaps I'm wrong.

Quoted from McMean

I'm no expert, but are those actually 'errors'?  I know with some machines I've had, if you go into test mode, it tells you what switches are activated, not necessarily 'errors.'  With BK, I'm guessing it should list those three switches - you have balls sitting on them so they're activated.
Just a thought, perhaps I'm wrong.

Hmmm, all three balls are supposed to be sitting up there, right? They're supposed to be activated, no? Maybe they're noted in the test because they're not being activated?

So confused ...

What he is saying is that if you have balls in the trough during the switch test, they are going to show up as activated. All the switch test does is tell you what switches are activated. What you need to do is remove all the balls from the machine, make sure all the drop targets are up. Start activating each switch one at a time and make sure that the correct switch number shows up on the display. If you get multiple switch closures showing from one switch then you have a problem somewhere. I usually print off a copy of the switch matrix so I can mark down what doesn't work.

Quoted from Grauwulf

What he is saying is that if you have balls in the trough during the switch test, they are going to show up as activated. All the switch test does is tell you what switches are activated. What you need to do is remove all the balls from the machine, make sure all the drop targets are up. Start activating each switch one at a time and make sure that the correct switch number shows up on the display. If you get multiple switch closures showing from one switch then you have a problem somewhere. I usually print off a copy of the switch matrix so I can mark down what doesn't work.

That's a great way to troubleshoot (and keep track). Thanks, James!

Huzzah! I found two dislocated wires near the left drop-target bank. That works again!

Last issue:
The switch test show 17, 18 (Right & center ball ramps) and the balls don't kick out on their own without manually working the Outhole switch (20), darnit.

Almost 100% ...  

Quoted from OTTOgd

Last issue: The switch test show 17, 18 (Right & center ball ramps) and the balls don't kick out on their own without manually working the Outhole switch (20), darnit.

Almost 100% ...  

Not sure about the ball ramps switches, but the lack of the outhole kicker could very well be poorly gapped trough switches. Make sure that when the balls are sitting in the trough, swtiches are making solid contact.

Quoted from McMean

Not sure about the ball ramps switches, but the lack of the outhole kicker could very well be poorly gapped trough switches. Make sure that when the balls are sitting in the trough, swtiches are making solid contact.

They're microswitches and not regular leaf switches. How do I check/adjust those?

Test them with a DMM set to 'continuity,' and make sure that when the switch button clicks, continuity flows.  Those switches do crap out, too.
I guess also make sure that when the ball is sitting in the trough, it is actually depressing the microswitch in the first place.

Quoted from OTTOgd

They're microswitches and not regular leaf switches. How do I check/adjust those?

Well, I re-flowed the solder on the switch connections and all seems to be okay now. Yay! I get to be bullied by the Black Knight again!

Thanks for your suggestions.