After years of neglect, I decided to play around with my bride (The Machine Bride of Pinbot). When I turn the power on I hear a loud zap sound that is coming from the back box (presumably the speakers?). It is loud! Zap! After the zap, the machine boots up as normal, however, it displays the Factory Settings Restored message on the DMD. When I try to use the direct switches on the coin door to adjust the settings, none of the the four switches work. None of the wires are disconnected, burnt, or show signs of problems. I unplugged all of the molex connectors from the board on the left wall under the playfield and that did not help. I opened the back box and reset all of the plugs and ribbon cables and that did not help. I removed the J205 connector from the mpu and attached a wire to the ground harness of the back box and touched each pin of the connector. Nothing.

The mpu LEDs light up as if it is a working board (LED 20 blinks and LED 21 stays lit, while LED 19 goes out after start up). I removed the mpu board from the back box and gave it a visual inspection. The sticker on the board has a date from 1994, so it is a replacement mpu board (TMBOP was built in 1991). I did notice some greenish white crust on some of the legs of the chips directly under the battery, which I lightly scrapped off. All the pins of the chips are firmly soldered in place by the factory. No repairs were ever done on the board. Other than the light crust on the chips' legs, the board looks like new! The batteries inside are new and there is no sign of previously leaked batteries. A few years ago the machine worked fine and I managed to get all of the high scores on it!

What is causing that loud zap sound on start up? Would replacing the mpu board resolve this issue? Thanks.

Thanks! I'm a big Avengers fan. I especially enjoyed the episodes that featured Diana Riggs as Emma Peel (M Appeal, short for man appeal...). In that picture, John Steed rescues Emma who is tied to a railroad track with an oncoming locomotive in the near distance. Great stuff!

None of the switches on the coin door or coin chutes give a response on the DMD. The batteries are brand new and the battery holder is in great shape. I will try to post some pics tomorrow of the board and the chips with the green stuff on them (now neatly scrapped away). I am planning on replacing this board and the mpu in my dead fish tales pin with new boards.

Now I am concerned about what is making that loud ZAP!!! sound when I first power on the machine. Thanks!

I too have all of the DVD sets! I got them when they first came out from AMC. I also have a DVD with some rare, previously lost earlier episodes from the early 60's. It is one of the rare shows that both my wife and I love to watch. Her favorite episode is The House that Jack Built and mine is A Touch of Brimstone (although with a lot of close seconds).

You dog!

No, there is nothing normal about that zap sound. I have never heard it on any other pin. However, it is consistent in that it occurs only once every time I power up the game. After that, everything seems normal! Also, when I shut the power off there is a zap sound but to a lesser degree.

There is no voltage across the pins on connector J205. I just ordered a new MPU board for this pin. I actually like playing the MBOP and I miss the bride's sassy comments. Thanks for the suggestions!

"Dog? Did you mean snake?"

"My oh my. Did someone say BRIDE?"

That is what I suspected - either a bad cap or a bad chip. But which one? If it were a bad cap, why does it only occur upon power up instead of all the time? Thanks!

No, it is an actual photo! From the Avenegers!

I'm not really sure, but I believe it was taken from the episode: Epic.

Well, I finally got to doink around with my bride in the basement this past weekend! I am happy to report that after over two years my Machine Bride of Pinbot is now in full operation! Yeah! It was one of the easiest repairs ever too! Thanks to my new buddy, Charles, over at the Pinball Basement in MN. He sold me a new CPU board that made this project a simple board swap (after transitioning over the ASIC, game chip and micro processor and adding new batteries). One of the first things the bride told me was: "I want more!". I still haven't gotten the high score yet. But it is now working 100% and no more problems with the onboard computer buttons not working and no more loud noises coming over the speakers!

Charles from the Pinball Basement was excellent to work with! I gave him a call to ask him some basic questions about the boards. I ended up buying two WPC MPU boards from him. He makes them at his location and ships them out lightening fast. The boards were packed well in a box and they look identical to the original boards. I also purchased an ASIC chip puller from him. So far, I am very pleased. I installed both boards: One in the TMBOP and the other in my Fish Tales. Both work perfectly. Here is the link to Charles Pinball Basement web site: www.pinballbasement.com. He is a Pinside member and posts on these boards all the time.

I know I could probably have fixed the CPU, but what a PITA! There are so many electronic components on the board it did not seem worth the time. For my Fish Tales, I already screwed the board up trying to replace a simple 8MHZ crystal. Charles also sells his boards at great prices.

Well, off to play pinball again! I just wanted to bring final closure to this thread and give kudos for Charles for his help!