Let's head to the manual! Particularly, the switch matrix on page 3-3.

doctor-who-switch-matrix.png

First of all, I don't really know Doctor Who too well, but I'll assume we're talking about switch 78 "Mini-ply Target" or "Mini-ply Lites Lock". (If I'm wrong, my logic will still hold up.)

At that target, there should be one or two white-gray wires on one lug, and one or two green-violet wires on the other lug. The simplest explanation would be that one of these wires have broken off the switch, but I think you've already ruled that out.

An equivalent problem would be if one of these wires (either the white-gray or the green-violet) had broken off on another switch, essentially cutting off switch 78 completely.

The first thing to do is check all the other switches in column 7 and row 8. If some of those switches are out, that will be a good sign that you're on the right track. If not, you're possibly still on the right track.

If you find a row or column that's partially out, you need to inspect the switch wiring at each switch on that row or column. You'll probably find that there's a wire broken off. You'll simply have to solder back to the lug with the same-colored wire. If all other switches are working, physically inspect each wire on the same row and column.

Hopefully you'll find the problem. If not, you'll have completed troubleshooting step one.

check under the mini playing field, the switch's, and solenoids have mutiple plugs (like 3 or 4) one might have came apart

mot is correct, but I would add, that this target has it's own connector. My guess is a bad connector and / or a break in the wire.

Follow the wires to the connector and check for the switch closing at the connector to the target.

Then, short the connector to the CPU to see if the switch close registers in test.

If both of those work, you have a bad connector.

If either fails, check continuity on the wires... you have a break.
faz

You could have a larger matrix failure. Check ALL the switches in test. Especially the optos in the MPF.
All the switches in column seven and row eight are suspect.

faz

Great news!!! Blast some Daleks!!
faz

Please never sell your DW Faz - you are our forum Timelord!

Glad you worked it out woodmedic, it's too good a game to be out of action. Hope Nate finds one soon.

mot and many others know FAR more about the electronics than I do. I just mapped out about 1 cu ft of a single pinball machine. So much to learn.

faz

Damn! I was going to suggest looking at the outhole switch in particular! That switch is quite exposed when lifting the playfield, so I've had problems with it before.