Just picked one of these up in really good cosmetic but a bit rough electronic/mechanical shape.
The opto board in the trough was interesting. It was reading closed all the time; the traces looked ok even under high magnification. Interestingly enough when I hit the receiver with a laser pointer it went open (as it should when it "sees" light) and on reassembly for both sides it's working... Hmmm... me thinks I'll get new LEDs for both sides and expect to have to change those again. In addition the HV board for the DMD had a couple of cracked solder joints at the connector that led to the DMD going on and off with vibration; easily fixed. I may put a ColorDMD in the game eventually....
I have one obviously-burned flasher transistor at Q32 on the driver board, but no manual (yet; I have one coming) so I don't know the part number. What goes there? The rocket and two backbox flashers are inop, all others ok; there are no shorts (currently) at the sockets but obviously there was one..... If anyone has the specs on the drive transistors for the flasher block (looks like 8 channels) on the power board that will accelerate my finishing work on this one by a few days.
The short in the flasher circuit was probably related to a (very) poor coil repair made to the kickout on the rocket; the connector block was rotated 90 degrees to the right (!) and thus the connectors were hitting on the metal of the rampwork in the vicinity when the rocket cycled. The bracketing was loose enough to allow that to happen; the only thing that probably saved me from another blown driver transistor was plastic insulating sleeves on the coil connections... at the cost of fractured wiring to the kicker that only worked some of the time. Disassembly of that piece of things to get the coil out and re-form the retaining bracket so it can't do that again was "fun" in a not-so good way, but it's done and now all my toys are working.
ALL of the bail microswitches on the playfield had their bails sufficiently compressed to prevent them from registering reliably -- or at all (!) Sega, what were you thinking with this design? Meh.
I'm a Williams/Bally guy and finding that the usual Williams/Bally attention to actually being able to get at things (e.g. GI, etc) is utterly absent with this game. There are usually a few things on a WMS/Bally that are a minor pain to get to, but nothing that's ridiculously awful. Sega, on the other hand, appears to have paid exactly zero attention to being able to access anything post first-assembly on the playfield. Double-meh; disassembling multiple layers of playfield being the *only* means of getting to some of the GI doesn't push my buttons at all, but at least with LEDs I'll only do it once.
I like the game and got it at a very nice price (don't ask, it was ridiculous) from a private owner who I'm reasonably sure knew it had serious problems and no idea how to fix it..... it's back to fully playable and with the few remaining issues (e.g. the flasher circuit) fixed it'll be 100%. I've mostly-relamped it in LED and find it VERY tight on shot requirements and really maddening (in a good sort of way) to score well (plus my kid likes it), so this one is likely a permanent part of my collection. Surprisingly it still had batteries in it and there was NO sign of leakage despite the PO having no idea they were there nor any evidence he'd changed them during the time he owned it. (!!!)