Problem: Dr. Who WPC Fliptronic II board blowing fuse #F904 which is to the left upper flipper. Fuse blows during flipper test mode or if machine is allowed to power up into normal ready mode. All other flippers function correctly.

Trouble shooting repairs: Confirmed coil tab wiring correct, Replaced coil as cautionary measure, Confirmed continuity in wires from board to coil, upgraded flipper board to Rottendog model.

Problem still present!

I am thinking possibly at this point that my J907 or J902 plug could possibly have a wire or two in the wrong pin location. I switched harnesses during my restore and no longer have the original. I attempted to cross reference the wire color pin placement with the Dr. Who manual fliptronic schematic section but honestly I could not pinpoint a confirmation or refute to my current set up. The pictures and pin# were confusing in their presentation. Could someone verify my pictures of these 2 plugs and their correct wire slot locations and / or some suggestions to tracking down this problem??? I am stomped at this point on a solution.

Thanks

J902.jpg J907.jpg

No Blow or function to any flippers if J907 unplugged.

Blows instantly! Not even time for an energize : (

With the Orange/Gray & Yellow/Gray wire already connected there is no fuse blow. When I then connect the middle black/blue wire to the coil, the fuse blows. I found no shorts on the actual wire route. This wire runs to J902 plug and the corresponding pin (#3) shows ground with DMM with power machine on or off. When I remove J904 (12v / 5v/ ground) supply to board the J902 pin#3 ground is also removed. Should this pin show ground? No other pins on J902 tested ground.

I was thinking also that F907 was incorrectly wired. I rewired the plug correctly using your instructions and confirmed this with the manual as well. Upon power up fuse 901 now blows instantly and the left lower flipper energizes after the machine wake-up test cycle completes or upon entering manual test mode. If I disconnect the upper left coil 901 fuse does not blow but lower left flipper still energizes instantly upon entering manual test mode. Man this is intense....I have been able to solve every other issue (and there were several) but this has me stomped. What do you think now???

I am going to replace the coil diodes on both left flippers and also check the transistors on the Rottendog board. I sent the original board to Clive because even after I replaced the Q5 transistor the same problem occurred. Here are pictures of the coil wiring and the 907 plug after correcting the wire pin locations(top pin is #1). What should the coil Impedance read on the DMM?? Thanks Mark and also you too John for the input. The 907 plug was definitely wrong so Im thinking now its a matter of finding what has been damaged or re-damaged as a result and correcting it before it repeats. The rottendog components look much beefier than the OEM board but I guess they can fry too. Let me start checking...

Right coil Right_Flipper_Coil.jpg
Left coil Left_Flipper_Coil.jpg
Upper left coil Upper_Left_Flipper_Coil.jpg
907 Plug 907.jpg

UPDATE: Q5 & Q1 transistors on new board damaged. DMM shows 0 on all 3 legs. These are MOSFET transistors so I have placed an order with Great Plains Electronics. R5 & R1 Resistors test Ok. Upper flipper coil diodes bad, removed and checked coil resistance=OK , new diodes installed. Lower left flipper coil diodes test ok but coil overheated and sleeve now un-removable. Coil replaced with new coil. Will update once transistors arrive and have been installed in new board. Hopefully this will solve the problem Thanks guys!!!!!

Great suggestions John, I will switch out the diodes on the right flipper also and search for a J902 match. Everything else you suggested is done! Thanks a bunch.

Damn you sure did!!! I was so caught up in this other stuff I forgot... Yep it's an exact match!! Were good there.

Update: Received MOSFET transistors from Great Plains Electronics. Replaced Q5 & Q4 on Rottendog board. Replaced all diodes on all flipper coils. Confirmed valid fuses. Installed board and confirmed all connections. Prayed.......Powered on machine, no fuse problems but left lower flipper energized after self check mode completed all other flippers normal. Rechecking all connections I unplugged J905 (opto board connector) and left lower flipper De-energized. Hmmm.... Unplugged Left flipper button opto board and replugged J905 no change. Well further investigation found a slightly bent flipper opto blade that was allowing only the lower flipper opto section to energize as if using the "ball cradle" tactic or slightly pushing the flipper button. Straightened out the blade and problem resolved. This obviously was a problem along with the miss-wired J907 plug that took out the transistors. Wow what a challenge this was but great, great learning session!!! Thanks again Markmon & John.