It looks like it will take a lot to fix them, if it's even possible. Hard to tell from photos, they would have to be tested with a meter. Even if so, with that extent of damage, they probably wouldn't be reliable.

Since the mpu has corrosion on the ground plane at tp4 which 10+ inches from there batteries it is probably not worth the effort to repair.

They are both salvageable. Depends on your determination, skills and what you value your time at. I do not think that you can find anyone who is willing to repair as the fee to do it right would be rival a replacement board cost.

And you can trust that this guy knows his stuff..

Trust me, repairing these is not an 'amateur' level repair. If you had the skills to fix something like this, you wouldn't be asking, you'd just sigh....grit your teeth real hard...and get to work. I tried to fix one like this before. It did not turn out well and all I did was destroy the thing even worse. I ended up buying a replacement from Barakandl.

Looks like at least 4 hours worth of labor on the MPU board and maybe 3 hours labor on the lamp driver board. If it were me, I'd reject these boards and suggest buying the reproductions.

Don't forget you're going to need to repin the female half of the connectors in the harness too. Judging by how bad the male half is, it's a cinch the female parts are shot too.

Repairable? Yes. I've fixed worse, because I hate my free time. Worth it? No. New boards are available, or you can find working originals around pretty cheap. Keep it for parts.

repairable? yes, economically viable?. no. suggest you buy an alltek board or your preferred similar option

As everyone else said and what I should have included in my initial response, I would just get reproduction boards. You can even find rebuilt boards for many older Stern SS games if you look, and usually relatively cheap. Quite a few games used the M-100 board. They are all over, and even on eBay frequently. I would get one from a reliable source though, as boards on eBay are commonly "untested" and not guaranteed. Some Bally boards are also interchangeable in older Stern SS games. AS-2518-35, used in games like Mystic and SBM.

And as Barakandl and Ken pointed out, the J3 male pins are shot, so the female connector almost definitely is as well. Given that, the female connector will most likely have to be repinned either way, even if you do get a replacement board. There is most likely corrosion and oxidation inside the connector, judging by what the male pins on the board look like. You should go through and repin every connector if any others are in the condition of J3 or close...just because you'll end up doing it in the foreseeable future anyway. Crappy pins in female connectors just lead to conduction issues Some of the traces on the boards are pretty rough as well, and you don't want to start bridging it with solder, or putting jumpers (hacks) everywhere. Plus your Q54 tip (TIP 102) is probably bad also...that transistor goes bad on practically every old Stern board I've come across. I'd follow Zac's advice, and just keep these for spare parts.

I don't think lamp boards are really worthwhile to repair when they have any significant battery damage. Maybe save the large chips if possible (if they're clean), and then recycle it.

The MPU isn't the worst I've seen. It's reparable. The header pins would need to go, though. If you do (or can do) the work yourself, it may be worthwhile. If you can't, it's probably not economical to send it out for repair since it's not a particularly expensive (aftermarket) board.

Agree with others, it is repairable, but you might end up pulling your hair out doing so. The only reason I would do it is if I wanted a challenge and to learn more about the circuitry on this board. If its just about saving money, clearly not worth it.

After purchasing a new mpu from barakandl ,there is no way I would put any effort on that corroded board. I don't think it's worth the time and effort. The new board is perfect and plug and play. Just my thoughts.
-Mike

I agree with the group. I could repair these boards. Would it be worth wild economically, No! If you have the time and equipment to fix them, would it be fun fix them therapeutically, absolutely! That said just get a board from barakandl then once you are done with the job of repining all the female connectors in your backbox you can play your game.

I would repair them if it was my machine BUT your mileage might vary.

IMO you can snag less corroded boards off eBay or Pinside fairly cheap a lot of times if you're not in a huge rush and don't mind a little bit of work. I've had people give me free boards a few times that had some small amount of corrosion that hit the 5101 socket and that was it -- just because they put an aftermarket MPU in their machine and the old board had no value to them. Not really a need to buy $150-200 board if you're comfortable doing some work yourself because of how many people are in the same situation without soldering equipment, replacing a board that has lighter amounts of corrosion and selling or giving away the old.

Bottom line is, markets change as cheaper options become available and people value their time more. So cheaper aftermarket MPUs = greater likelihood of finding less corroded boards that are easier repairs.

Fully agree with others, that board isn't worth the trouble. Keep your eyes open, or post a wanted ad for MPU boards with light amounts of corrosion. They're a dime a dozen and most people would probably let 'em go for under $50.

Just my 2 cents

You will never learn board repair unless you do it. What do you have to lose?

Milage may vary? Wait, is that like when the bottom of the car commercial warns you that it was a closed course and driven by a professional stunt guy?

Really though, sounds like whole group on mostly the same opinion. If you have the skills/tools to do the job, it can be repaired at the cost of many hours (I too do it quite a bit on my own boards). Also good for practice if you need experience, since you aren't going to hurt a board that can't be replaced or anything.

Reliability of repair vs new board?? Well...to quote homepin again, lol

Mileage may vary.

The amount of work that's already been done on this board concerns me. U1 socket missing. U11 socket replaced. J5 looks sketchy. If there's anything wrong with J5 the board will have issues and may not even boot.

The lamp driver could be salvaged, but why when you can buy used ones in decent shape for $10-15.

Working on this board would be like surgery on dead people, what's the worst that can happen? You get a pulse?

.






apologies to Dennis Miller for paraphrasing his joke

Wise choice

You are okay with the voltage. SDB main cap can sometimes hold a charge but it if has not been powered on for years then you are okay.

If you see a medium/big cap on board, discharge it. Why risk a zap?

Proper way is slowly under load, but shorting the terminals with a screwdriver or something most likely wont hurt anything.

I am not much of a fan of the attitude of "oh ... it should be ok" or "it hasn't been on in a while"...

Just short it and make sure in my opinion.

There are some decent repair tips in vinegar, water, alcohol rinses to neutralize the acid as well floating around out there in repair guides.

The wrinkled masking on the traces on the entire board is normal.

Vinegar doesn't actually do much of anything. I use Zep now. It's more acidic and you can actually see a chemical reaction with the alkaline leakage, which actually removes most of it.

https://pinside.com/pinball/forum/topic/stripping-battery-corrosion-with-a-strong-acid

Thanks, glad you're happy with it

Interesting, I believe it was a clay guide that had the method I mentioned. I'll have to check out your suggestion. Thanks F.F.

It was mentioned in a lot of places. I used it too because it was pretty much the go-to approach. But I always kind of wondered how effective it actually was since I could never see the vinegar actually do much of anything.

Once I saw zep work and clean off the alkaline residue, it was obvious that vinegar was not very effective. It simply wasn't acidic enough to counteract the alkaline.

So, as time goes on, people try new things, and better techniques sometimes surface to replace older ones.

image.gif