Today I paid a visit to Pintucky and we spent about 3 hours total looking at his game. Here's precisely what we found:
Munchkin Lock
First of all after reverting to 1.18 Mike was having trouble with his munchkin hut lock release coil. It would work fine in switch test mode when I sent a ball up the ramp, lifting up and allowing the ball to pass through. The issue was it would not release upon the third ball lock after the multiball start sequence. It would also not release during a ball search. I also believe this to be the case with 1.24/1.25. If that happens you have to pull the glass and free the balls manually, even entering the test menu and leaving would not release them, niether would cycling the power on the game.
So I went into coil test and tried to fire it in the manual coil test using the start button. Nothing happened. Earlier he took off the munchkin hut plastic and checked the coil and opto wires and found no issues. I also tested the optos by stacking 3 balls behind the lock release in switch test, that worked perfectly and I pushed the 3 balls around and there was no fluttering of the opto switch closures. This is not an opto problem. So then I decided to isolate the coil itself by jumping its drive transistor on the driver board. The coil fired both times I did this with the playfield sitting on its rubber bumpers in the forward service position. The playfield was not moved at all from when I tried this in coil test. So now we know it's a software related issue; not a 70v drive circuit problem, and not a driver board problem coming off the PC motherboard. I also noticed two fuses with no lights/voltage on the driver board but considering the board is not fully utilized yet (or even fully stuffed), I chalked this up to normal by design. Something is really screwed up in the game software that causes the munchkin lock not to release when multiball starts and in coil test. And speaking of software, I also meant to hash the 1.18 ISO file to check for errors but ran out of time. I'm assuming it's fine considering the machine booted from the unetbootin drive and installed successfully.
But here's the kicker: We reinstalled 1.18 fresh and, after fixing the LEDs, the coil started working again. It was doing fine at the start of multiball, and the timing was perfect too. It seems to be a completely random problem, some games it will work, some it will not. But to my knowledge this is the first time it has worked in gameplay since he started having this problem back in September, which correlates with his numerous LED board failures. The game still tends to lose track of balls about 5 minutes in, sometimes you will drain and it won't call the drain sequence, others you will have a ball already in the monkey lock at the start of a game, other times the machine will not release locked balls from the munchkin lock at the end of a game. And all of this started happening when the first LED board failed. This machine was rock solid when I played it in early September and my extensive gameplay video proves it. There is absolutely a correleation between board failures and strange playfield behavior, regardless of what you were told. Like the crystal ball connector, the serial chained nature of the LED boards causes garbage data to be returned to the PC when there is a failure and negatively affects the entire game's operation.
LED Boards
When we started, half of his playfield lights were out. All the GI was fine besides one connector that came loose which affected no more than one or two GI lights. He quickly found the culprit board, replaced it, and we were rocking and rolling (mostly). His new 7.5v W1 board is failing again evidently, one of the LEDs is glowing orange instead of yellow. Also, the top TNPLH inserts lights bluish when it should be completely off. Other than that everything else seems fine. As I mentioned once we got all the LEDs going again by replacing that one board the munchkin lock started working again like it was before any of these failures. I checked the voltages coming from the bottom terminal of the 5v LED power supply in the very back of the cabinet against the back wall and I got 119v going in (normal) and 5.20 volts (!) going out to the purple and black LED power supply connectors. This is somewhat alarming, the voltage coming off this supply is 0.2v too high. I can't think of a reason why this would be the case, but it could very well be contributing to the failing of both his old 5v LED boards and his new 7.5v ones. Mike, as well as others with 7.5v failures, should demand JJP send them a new 7.5v power supply, unless it has been proven that a new 7.5v supply in combination with all new 7.5v LED boards does not solve the problem (or prevent it from ever occurring).
Also when looking at the boards and adjusting a rollover switch I noticed the boards are mounted very close above those switches. This is clearly a bad design, as the back side of these LED boards can short out against the metal leaf switches they are mounted to. Could these be causing some of the LED failures? I didn't see any shorts on this machine, and some have reported blown board fuses, but food for thought...
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Sound
For the past couple of days the sound on Mike's game started acting up. This is the latest failure on this particular machine. The sub in the cabinet lost all sound and it seems to me like the 2 channels in the backbox are out of phase. The sound seems unusally tinny and lacking bass, and the witch's voice can barely be heard when a game is started. This sounds like a capacitor failure somewhere on the audio amplifier board underneath the metal cover of the PC box above the SSD hard drive to the right (the Pinnovators audio board). Also, there is a distinct whining noise from the top speakers in the background, sounds like a ground loop. I hear this as soon as I turned on the machine, so it's not coming from the PC as it had not booted yet. Also, I notice some faint noises as the PC was starting up, similar to the digital noises you would hear when connecting headphones to a laptop. Given this I am also suspecting a ground loop of some sort is causing/contributing to this noise. We checked cables and connections both outside the PC box and under the cover, and didn't see anything loose or disconnected. The audio line out jack in the back was also fine, as it has been a suspected cause of this problem on other peoples' games.