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Me too! There’s lots of nuggets of gold in it but this one is my favorite.

You're in Tempe? There's a local repair party happening this Sat. in Chandler, unfortunately I'll be out of town but @Arcadenut and @BigDogs will both be there. If you are using a Happ gun I'm assuming you are using one of my FPGA boards since the original gun works on 12V not 5V?

One other failure mode I've seen but forgot to mention, the volume pot. I've seen them get pretty noisy and even have "dead" spots where there's no continuity so I'd check that as well.

For some reason I thought it did, I rewired a couple of them for a friend but I also did an upright so maybe I'm confusing them OK then at least Pin 16 and 10 of the cable is making connection and the '259 on the CPU is not COMPLETELY dead, still could have 1 or more bad outputs though. Do the...

Andrew is trolling you, he’s not the brightest bulb but I’m pretty sure he’s not THAT dim. Both of those transistors were clearly fine, if you have ANY hfe (forward current gain) then the transistor is functioning. I’m curious what Uf is, it looks like maybe Vbe or Vce sat but I’ve never seen...

What does the self test show?

Did you check to see if you have a signal on J4 pin 16 on the CCPU? (OUT7). If you have 2 audio boards doing the same thing it's very likely either the OUT7 signal on the CCPU is bad OR the 16 pin ribbon cable/connectors are not getting the signal to the audio board. If you just want to...

It measures inductance which is the primary design parameter in a yoke. The number of turns and physical dimensions are directly related to inductance. Resistance is “loosely” related to inductance since it gives an indication of wire length assuming the wire gauge is the same but if the wire...

I didn't realize you hadn't solved this yet. Do you have a Fluke 9010?

It looks like you have some RAM issues. When you say "bombed immediately" I'm assuming you mean the player ship explodes immediately? This is likely caused by some of the stray extra pixels you see on the screen triggering the "hit detection" in the U15 custom as soon as the game starts. It's...

Sort of, the clock speed stays the same but the "game clock" controlled by the IRQ interrupts is normally 60Hz but would change to 120Hz or 240Hz. But yes, all motion objects would speed up. You could make just the player speed up but that's a bit more complicated than this solution. The way the...

Yes, the game speed is paced by IRQ which is normally VBLANK or 60Hz. When you press the button it switches one of the other vertical counter signals to IRQ to speed up the game play. You can do this with several different ttl parts 74LS00, 74LS02 etc.

Other than age, the two factors I can think of are: 1. The uptick in people "repairing" POKEYs by baking them, which as I've mentioned previously is a dubious practice that likely "temporarily" gets them working for a short time. 2. More people "repairing" boards by scavenging good parts from...

It sounds like the x and y joystick signals are tied together. The game alternates reading the x an y joystick pots by driving OUT7 (audio connector J4 pin 16) high for horizontal (X) and low for vertical (Y). It then receives the appropriate signal through J4 pin 10 which is the “external”...

You might want to watch the video the OP posted. It shows clearly that blue is NOT missing. In fact he disconnects the red and green and leaves ONLY the blue and there's a complete picture on some of the screens. Your whole post will mislead him. This is why I assumed green and blue were...

Yes, there is something "special" about 128H and /256H. Your "expected" value for these bits is incorrect. Because the counter is reset/reloaded BOFORE either of those bits completes a complete cycle they are both "shortened" to the overall horizontal frequency which should be close to 15.75Khz...

what color was the wall with the swap? Did the yellow wall become purple? "worse" isn't really a helpful description, maybe post updated vid?

It looks like you might have green and blue swapped. Maybe a test cable/connector issue?

A scope would have found this where a logic probe wouldn’t. The logic probe just shows pulsing but the scope will show right away that you have more than one signal driving the trace. Fluke 9010 bus test would also show this immediately. You still have to find the short but you would know which...

OK, you were at least trying two different original boards not just one. Were you able to get to the screen for the sensitivity adjustment? What did it show? The reason I ask is that screen shows the optical detection continuously (without having to pull the trigger) looking at that screen gives...