Author: James R. Twine
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WG6100 w/Tempest Showing a Multicolored spot in Center of Screen
So I was helping a newly minted arcade game owner when his first purchase, which is his favorite arcade game: Tempest. Shortly after getting it the X-Size pot fell apart and the game ended up only showing a Multicolored spot (larger than a just a “dot”) which changed depending on what the game was doing. …
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How a Screen Full of Garbage can be a Diagnostic Indicator
(This is essentially a copy of something I posted in a Facebook arcade repair group not too long ago.) I was replying to a post that had to do with a game that was showing garbage on screen but was otherwise not working. The type of garbage you see on screen can actually be a…
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Lithium Battery Replacement for Williams and other CMOS Systems
So you have decided to reduce the risk of battery leakage damaging your precious Williams arcade or pinball board by replacing the existing AA batteries with a lithium (CR2032) replacement. Great! Lithium batteries like the CR2032 tend to leak much less than alkaline batteries so this is a good generally a good idea. Note that…
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+43 Volt Error on a Alltek Systems Replacement MPU Board
So I was helping another collector in the area try to get a Bally Star Trek Pinball running. It had a Alltek MPU replacement board it in that would start to boot but then stop with 5 diagnostic flashes which indicate a problem with the +43v supply. However, when metered at the test point, the…
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New Language and Compiler for the Fluke 9010A
I have always been fascinated with the older Fluke 9010A microprocessor troubleshooter. I have owned a few through the years and my current bench one has the serial port on it for transferring programs and data between the unit and a PC. However, I never found its programming language (usually referred to as 9LC, the…
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Frogger Problems
So I visited the arcade of someone I have come to know and while taking a look around and playing a few games, I stumbled across this screen on a Frogger: Not exactly playable, if you catch my drift. Went over the usual stuff, power, reseating, etc. Voltage was a little low, and the power…
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Fuse Voltage Ratings
Everyone knows what the amperage rating on a fuse is for and what it means. But do you know what the voltage rating is for? Maybe not what you think. Quite a few people think that the voltage rating of a fuse indicates the voltage that the fuse will blow (or break) at, like what…
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Galaga/Bosconian RAM Tip
Galaga uses 4-bit RAMs. This means that in order to handle 8-bit data, it needs to group RAMs in sets of 2 – one for the lower 4 bits, and the other for the higher 4 bits. When Galaga detects a RAM error during the self-test, it does not show the location of the failed…
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Dead Vanguard Board
So I came across a dead Vanguard that was for sale. Described as only producing a boom sound effect and then a rumbling/static-y noise. Bought the thing home along with 1.5 spare boards and did the usual checks: Power, Sockets (reseat), etc. Logic probe on the CPU indicated that it was briefly running and then…
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Quick Fluke 9010 Tip
If you use the Learn function on a board, and it seems to ignore an certain part of the memory map that you know for sure is a certain type (e.g a section of the memory map allocated to RAM), run the appropriate test on that area. Bet it will detect a problem with it.…