Note:  I do not work on Pachinko machines.  Although I’ve worked on a few over the years, I will not work on them any more.  Nobody I know wants to work on them either.  Sorry.

Yes, it is April Fool’s Day, but no jokes here.  I received a call to repair a pachinko machine.  I pretty much focus on only pinball machines, but hey, why not?

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Star Trek the Next Generation – upper diverter

Edit 12/9/2018

If you are having issues with the diverters on STTNG, I recommend reading through the writeup at Pinwiki found here.  I especially recommend doing the modification to move the tieback wire and run it directly from the driver board to the auxiliary driver board.

As an update to the game that is discussed below, the problem with this game continued for years.  The upper diverter would lock on, cook the coil, and blow the fuse.  I had done everything in the Pinwiki article to no avail.  The game would work for quite a while after repairs, but eventually it would lock on the diverter again.  It seemed the game was possessed.  It was finally determined that the issue was the ribbon cable that runs from the MPU board to the little auxiliary driver board.  The game has been running trouble free for over a year after the ribbon cable issue was diagnosed.  New ribbon cables can be ordered from Great Plains Electronics.  Also realize that the problem can be the connectors on the MPU board and the auxiliary driver board.  So keep this in mind while trying to diagnose and troubleshoot issues with the diverters on STTNG and other games that use an auxiliary driver board.

Below continues the original post regarding this issue:

I had the opportunity to work on a beautiful Williams Star Trek the Next Generation (STTNG).  The game was not loading the under playfield balls correctly and was cycling the loading sequence.

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Comet System 9 High Voltage Repair

Note:  This repair was initially published on Sept. 19, 2011.  I republished it with updated photos and information.

I received a call for a Comet with non-working displays.  I was told that there were no blown fuses, but the displays just stopped working.  No blown fuses indicates a problem with the power supply.  I was hoping this was the case as troubleshooting alphanumeric display problems is not a lot of fun in my book.

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Data East Sound Amp Repair

I was working on a Data East 520-5002-03 sound board that had no output to the cabinet speaker.  The cabinet speaker was blown, but there was still no sound output when using a known good speaker.  I now suspected that the MB3730A amplifier on the sound board had blown out.  When it goes out, it can take the speaker with it.

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Odd Data East power supply

I was repairing a Data East power supply for a client and started off with the typical suspects.  Capacitor C2 was clearly no good, it had spilled its electrolyte on the PCB and had to be replaced.  This is fairly common because C2 is located right under the large heatsink, and it gets baked to crisp and dries out.  C2 in the photo below is shown as an example, it is not the suspect that leaked.

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