Category: Arcade Tech and Repair
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Possible Bug in Bally Pinball Firmware?
I am seeing something across multiple classic Bally pins that makes me think it is an actual bug in the firmware. It has to do with the LATCH signals for the displays. Specifically the Credit/Match/Ball (CMB) display.
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Quadrature Encoding Refresher
Quadrature Encoding …is the method used by mechanical mice, trackballs, and spinners like those used on Tempest and Arkanoid. It works by attaching a movement axis to a slotted wheel and placing the slots in between two optoisolators or optos. When talking about Quadrature Encoding, the two signals from the optos are sometimes referred to…
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Alltek Ultimate Solenoid Driver Board with only the +43 VDC LED lit
So I have a stand-alone Mata Hari headboard that is used for testing purposes. I previously had a Alltek Ultimate Solenoid Driver Board (USDB) in it that was powering an Alltek MPU board. That USDB was pulled because it was needed for another purpose and I later received a new USDB as a replacement. However,…
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Bringing Games or Pins to a Free Play Event (e.g. Free Play Florida)?
We all love our vids and pins. And for those of us that repair and/or restore older games, most of us are proud in what we have done to return them working again and bring them back to their former glory. And we might like the idea of sharing them with others at an event…
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Replacing Bad Customs’ Sockets on Galaga
Had a Galaga that was reporting false ROM errors and had glitching that made me think that the three CPUs were uncoordinated. For example: Game would sometimes play but would have no sound, would play glitchy sounds, or get stuck on sounds Game would have odd graphics-related issues during its startup or sometimes during play…
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Odd Display Issue in Gottlieb Haunted House pin
So I was helping a friend with his Haunted House (HH) pin. The bottom playfield stopped kicking the ball back onto the main playfield, and the two right score displays and the center credit/ball display would distort on a cyclic basis – they would show all segments in a flash-flash-pause, flash-flash-pause pattern, and this happened…
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Got Screwed by Suzo-Happ
So a site I work with has had two GamePro monitors go down. One of them was from an odd power issue that ended up smoking one of the Zeners on its control board, and the other was just a loose power connector. These boards use a lot of smaller SMT components that I am…
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Newest Version of AR-II Documentation
Atari Regulator/Audio II (AKA the A/R-II) Version -02 Information By James R. Twine (jtwine@jrtwine.com) ©2009-2026 Latest version available online at https://www.jrtwine.com/blog/?p=590 References and Source Material Information is this document is from personal experience with these beasts, and some was stole^H^H^H^H^H… um, I mean… inspired… from many sources including official Atari docs (wiring diagrams, schematics)…
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Galaga Board with Enhancement Pack not Booting
I finally got around to working on a Galaga board for AM and I got it up and running and was leaving it on for a 24-hour test when it crapped out showing a error on ROM 39 (which does not exist). This eventually degraded into a state where it did not display any errors…
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Theory of Operation of the Shaq 27722-1 (A23) LED Display Board
Theory of Operation of the Shaq 27722-1 (A23) LED Display Board (4-player score board).Theory of Operation of the Shaq 27722-1 (A23) LED Display Board (4-player score board). Theory of Operation This is a brief technical introduction to the operation of the 27722-1 (A23) board. It will cover inputs and behavior of the board. Inputs This…