Curious issue in GOTG. Groot's mouth moves on its own during attraction mode. The mouth motor is disabled in the settings. But when I look at the playfield, I can see some of the lighting is also misbehaving.

This game has a really poor design choice when it comes to the board that drives Groot's mouth. It's controlled over SPI bus and it's the last device in a long chain of LED boards. When they develop an electrical issue with the connectors, in addition to less critical lights control issue, the game's main feature gets messed up too. It has been so unreliable that most owners just use software locks instead, like I do too.

So imagine my surprise when after disabling the motor in the software I see it moving like this! I need to figure out which connector is bad and then probably just pull the motor's power cable so this won't happen again.

#pinball #pinrepair

A fun bonus fact:

Even though the score displays have 6 digits in them, it can only control 5 of them. The last digit is hardwired to zero, just as old electro-mechanical games have fake reels that add zeroes to the score. This is why it's diagnostic error codes also always end with a zero.

#pinball #pinrepair #electronics #retrotech

Today's head scratcher is Take Five's credit display. It loses a segment when it heats up and it also has one segment that's always a bit dim.

The resistors measure fine, but I'm not seeing the operating voltage coming through this one segment's LED. I check them with a thermal camera but nothing seems to heat up out of ordinarily. I hope it's not the 7-segment itself as this model is getting rare.

Then I make an accidental discovery, the issue can be triggered by tapping the board, but it's not a cold joint. I end up replacing the whole 7-segment, which as an added bonus took care of the dim segment too. Wasn't that mysterious fix today.

This board is pretty simple, it has a shift register, two 7447's to run the 7-segments and then couple of passive components. The score displays have similar design, just more displays to control.

#pinball #pinrepair #electronics #retrotech

I finally had time to put Doctor Who's mini playfield back into the game. It's always bit of a chore as it's a very tight fit. I did stress test the new part with a hammer, but it was still a bit unnerving to see the new bracket getting hit by a pinball over and over again, but so far it seems good. The new opto boards also seem to work as during the testing phase.

The doctor is back in the lineup!

#pinball #repair #pinrepair #arcade

After replacing the beaten up rubber grommet, I had a chance to show the effect a new one has. See how that bounce is just completely gone? This is how they were fresh out of factory.

#pinball #pinrepair #repair

Since Doctor Who's mini playfield is getting its spa day, here's the 3rd level mechanism. The 3 Daleks are flyaway targets, a relative of drop targets except they get hang off something and turn horizontally when hit. Not that common mechanism, I think Bally's Speak Easy had bunch of these.

They have a small metal flap to keep them in the "dropped" state once you whack them with a ball. There's a unified release mechanism for all 3 at the side, which is actuated by a roller just below the playfield.

The game has to take the whole mini playfield down one level to reset these, which is why after each jackpot collect it seems to go down and then back up for no apparent reason. The game doesn't know their status, there's a normal micro switch elsewhere and these are purely ornamental, you can score the jackpot even if they were all missing.

#pinball #mechanism #pinrepair #mildlyinteresting