Doctor Who
Bally, 1992I recently disassembled and reassembled my Dr. Who for a restore. When I put it back together it now keeps instantly blowing fuses F106 & F110 and giving me a message on the DMD "check switch mini opto 5 bank 71, check switch mini opto 5 bank 72, check switch mini opto 5 bank 74, check switch mini opto 5 bank 75". Does anyone know what I've done and how I can fix it? Thank you so much for your help.
A quick update. I reflowed the solder to all the wires and optos on the 5 bank opto boards on the mini playfield and I still get the errors.
I'm not very good on the electronics, but since nobody's playing. I'll give it a crack.
Seems to me there's two issues. Let's start with the fuses.
F106 manages G.I. Circuit #5 - White/Violet - Playfield insert 'C' off J120
F110 manages G.I. Circuit #1 - White/Brown - These are insert lamps off J121
Check out this amazing piece of GI Doc provided by Freds
https://pinside.com/pinball/forum/topic/doctor-who-general-illumination-memo#post-1281347
Probably, you have a solenoid shorting out into the GI. Trace GI #1/#5 around the PF to see if something is touching a socket.
I had a problem where a solenoid lug over many years of vibration cut through the insulation on the GI wire. Look closely at the insulated wires to see if they are laying over the lugs and or a sharp edge on the PF. Since it appears that the fuses don't blow on startup (the other switch errors), I assume you do something to trigger the fuse blowing. Pop bumper firing, flipper, etc. Have you isolated the catalyst?
As for the switch errors in the mini-playfield, that's a different ball of beans. However, I'd get the short figured out first. The MPF is one area I can help out.
faz
Thanks so much faz! I didn't have my flippers attached because that is the last thing I usually do. I noticed one of my flipper mechs was hanging low enough to touch and short out a GI socket which was blowing fuse F106. I reattached all the flippers now fuse F106 doesn't blow anymore at start up and all my GI is back on.
However Fuse F110 continues to blow at startup and an entire string of lights is out behind the back box translite. I looked at the string of wire connecting all the lights back there and I did see an exposed wire that was touching a metal piece in the back box. I put electrical tape over the exposed wire and thought it would solve the problem, however it didn't 
any ideas??
Good news about String 5.
As for string 1, it's off J121. Pull the connector on the power driver board. Boot up. Make sure the game boots and F110 does not blow. If it does, I'm way out my league now.
When the fuse goes, is the backglass panel hinged open or closed? Try it with the door open just in case something on the boardset is brushing the circuit. What about the hinge point where the wire floats off the board.
Does that look ok?
faz
btw... let's start taking about the MPF switches. It it currently generating new switch errors, or perhaps are these old.
Go to test, where you see these messages. I forget which menu, but possibly both:
Switch test
Test 14
Both of these test the switches for the 5 buttons. While in test, hit the "Credit" button. This will reset the counters. The message should go away. Again, not sure if in switch test / Test14 or both.
Do the errors continue? If they do, it's interesting because not all 5 are out... just 4 of the 5. That means the connector as a whole is still working. Also, the common on the emitter/receiver is working too.
So, sad to say, the next step is going to be pulling the mini-playfield. I wrote a whitepaper to help with this.
Scroll to the bottom of my "website"... you'll see the PDF.
https://sites.google.com/site/pinballfaz/
Once you get it out, we'll be able to localize the problem pretty quickly.
faz
OK so I decided to leave the fuse problem alone for now and move to the mini playfield. I reset the 3 errors in the mini playfield test screen, then rebooted machine. Now I get all 5 mini opto errors (71,72,73,74,75). So I went into the single switch test mode and test each little button individually. They all registered fine in the switch test. So I started a game and yup they work perfect, you can play a game with no problem at all and they register just fine? When I hit one with the ball it counts down from a number let's say 15 and continues to count down for a bit like it is still being hit by the ball, then stops. So I hit it once and it says time factor 15, 13, 11, 9 then stops until I hit it again, but I think that is just part of the game depending on which doctor you choose. So the mini optos seem to work perfect but I still have that error on start up???
I'm confused. It throws errors for all 5 at startup ... but then it works in test?!?!
If that's the case, I'll guarantee a broken wire or a loose connector. At startup the wires/connector droop the most. To test the buttons, the MPF must raise, changing the shape of the wires and perhaps pulling the connector contacts back together.
Re-pinning the connector is kinda a PITA unless you have a pin removal tool...so, I'm going to suggest you try something a little less intrusive as a test.
Reset the errors again; then, push the connector (the big 12 pin connector) together really tightly. Then use electrical tape to overtape it together to make the connection consistent. Test again. My guess is that either all 5 buttons work all the time or none of them work. The chance of a broken wire is probably slight as it would not "work", "not work", "work" that reliably. Feels like a bad connector. If everything works (no errors at startup AND no issues in test), repin the connector. There's other tests we can try, but that involves pulling the MPF out.
DR 7 is very "generous" in completing the matrix.. but it should not give that many.... but then again, I don't know what options you have selected. There's a few feature options that make it easier/harder. I might change the settings to factory defaults to make sure we are not shooting an issue that does not exist.
faz
And boom! I don't know how you knew but I duct taped the connector for the mini playfield optos together like you suggested and no more mini playfield opto errors! Yeah!!! Now to tackle the F110 fuse blowing but I ran out of 5A fuses so it will have to be another day. Thanks faz you're the best! I wish I could give you a million thumbs up 
Whoot! Nice!
So, now you need to swap out those connector pins.
Did you try pulling J121 to see if the F110 stops blowing?
EDIT: I'm guessing you did not have a chance to try the pulling of J121 prior to the MPF connector temp fix.
Ya know... you do have another 5A fuse... it's stored in F106 (you know that one works)... just sayin
faz
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