I am going to assume you acquired the machine with problems right from the start? If so first thing I would do besides testing all diodes is to compare the wire colors and diode connections match the
Schematic. Also note the three solder tabs on switch two are actual leaf for switch and one is a No connection floating solder point for wire and diode connection. Many time diodes installed backwards and or the switch wired incorrect so diode is not even in the circuit.

Alkaline damage on the cpu is always a possibility when you get random switch matrix problems so post a photo of the cpu board. Since it works after warming up I would check the following: Inspect the row and column connectors for any oxidation on the pins and make sure the wires are fully inserted in the IDC connector. If any of the matrix chips have been replaced and a socket installed, make sure the chips are fully seated.

Another suggestion is to double check the orientation on all the diodes on the micro switches where you are getting weirdness. I ran into a similar situation with my newly acquired DE Star Trek. I found a reversed diode as well as incorrect wiring to the switch. Once everything was in it's correct orientation, multiple errors were erased including phantom switch closures and errors in switches not registering in gameplay.

The board boot though, so it passes the PIA test, so not likely the switch PIA going nuts. Check all your 2n3904 switch transistors for shorts. A shorted out transistor can cause phantom switch activation. I think it'll just lock on if it is shorted. If it is randomly bouncing around, it could also be a bad SIP pack that is cracked on the switch matrix. SR15 is the part, next to U40. BTW, I'm in Hillsborough if you're really in a bind.

Post a picture of your MPU.

I don't think it is a switch issue. Probably a faulty solenoid driver TIP & or pre-driver. If the coil is just locking on, that is what is going on. Looks like that area was reworked at some point from the can type transistors used, the soldering on the back for U17 and jumper on the back too. Check all your coil driver TIPs & pre-drivers in the lower right of that board photo for shorts. Also this is a High Speed, but your EPROMs read pinbot. Did you wipe and re-write these EPROMS? Probably a good idea to put a sticker over the UV window on those exposed ones as well.

At the top of the thread OP says the outhole trips 5 times - even with all switch lines disconnected. Sounds a bit different than a simple coil circuit locking on or a switch problem. At first glance, that would seem to be some kind of upper level logic problem of some sort. Perhaps even related to the EPROMS as you noticed. I wouldn't rule out a PIA problem just because the game passes the PIA self test. I've seen PIA related failures with no CPU acknowledgement. My advice would be to send that board to a pro for a diagnostic.

Good info Wayout, as usual. I've seen PIA switch issues that have passed test on corroded boards as well. I was just trying to eliminate some simpler more common DIY stuff first. But since this board has seen work on it before, it could have to do with that prior work.

Probably best to send it out Dzrossi, rather than take the risk of damaging it further.

That rework looks terrible--with all of those lifted pads I doubt if the solder was flowed through to the other side of the board properly. As thedefog suggested I would send that board out to a pro, that entire area needs to be redone.

High-Speed_(resized).jpg

Looks like a lot of areas need to be redone. Lots of messy looking pads on that side unfortunately. May as well get new headers put on there too while you're at it.

I'd ask him for $ back honestly or return that board. I wouldn't trust whomever did this work to do "better" work. It looks pretty sloppy.

Take some pictures of your alkaline damaged board. If it isn't too badly damaged, that may be an easier fix honestly.

You've only arrested the surface corrosion with cleaning, you can see where either through capillary action electrochemical migration it has gotten under the solder mask (the dark areas indicate corrosion) and is eating away at the copper traces. Where the component leads enter the component bodies the corrosion will continue, so to make it long term reliable you will also need to replace components. I'm a pro with over 25 years of experience, the right tools, and high power magnification - and like Clive, I'd pass on attempting repair of that one. I've rescued a few Bally boards with alkaline damage.

If you have the workspace, tools, skill, patience and motivation to do it this kind of thing can definitely be done but it's a chore. I would suggest you get some very fine solid copper wire as well, it will work better and be more controllable than a solder bridge especially if there are larger areas of the trace that's eaten away. Good luck!!!!

I fixed a board in similar shape. And I wouldn't do it again. Sanding the solder mask off those fine traces that run from the PIAs to SIP resistors to board headers, just revealed most of them were completely eaten away by the corrosion. They are very thin, fragile traces that don't survive a heavy amount of corrosion in that area. Makes sense other people are telling you it's not really repairable. I had to use jumper wires between the PIAs and SIPs through-holes.. and then between the SIPs and headers. Probably a few dozen traces were completely eaten away. Even that probably only bought limited time on the board.

You're very likely going to be in that same situation from the looks of it. Stitching with solder / thin wire to repair the traces probably isn't going to be possible since the traces are so close to each other. Hey maybe you'll get lucky and they won't be too bad when you reveal them. If you bought the board refurb'd tho, the seller should be refunding you IMO.

The act of sanding will destroy what is left of those fine traces, and repairing those fine traces is usually not possible. I mean it is possible, but the amount of time needed to do it would be incredible and not really worth it. It sucks repairing those tiny little traces. Doing like 1 or 2 isn't too bad, but you'd probably have entire sections that are ripped up with like 10+ traces on it.

If you want a roached SYS11 practice board to play with, I'll give you one. You'll at least know what you're getting into.

I'd work on a refund of that "refurbished" board immediately before it is too late and find another one that is in good shape.

If you decide to go through with this repair, I would avoid passing this board off to someone if this game ever be sold.

Good advice here. You wouldn't want it coming back to bite you in the ass.

You can modify a 11a board to run HS, and those are more common because of all the pinbots that were made. Not too tricky to do either, since the sound sections are populated already.

I think you can also use a 11B or 11C if you stuff all the missing audio components (if you can source them easily). Maybe HS is different? Not entirely sure, but I've done this for several 11C's to get them running in older games, including my pinbot.