(Topic ID: 238668)

How to clean a Williams WPC89 Board with some little acid damage ?


By aurelwap

7 months ago



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  • 14 posts
  • 10 Pinsiders participating
  • Latest reply 7 months ago by robertmee
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WPC89 MPU entire board (resized).png
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#1 7 months ago

Dear all,

Firstly I must say I am a newbie with very limited knowledge so please excuse me if my question or diagnostic is basic. I purchased a BOP for a decent price and thought this is a cool occasion to start my first pinball repair project. Globally it looks like the machine was not given a lot of care, some ramps and plastics are a little damaged, the playfield is very dirty and shows some little wear but not completely worn out. As far as electronics goes, I was not able to test it when I bought it because it was not working anymore and the previous owner did not know why. The man who sold it to me was not a huge pinball fan and had no intention to repair it, he only had this machine for fun to play with his kids, he said it was working correctly until a couple of years ago, but then he did not use it for several years and he left it in his basement (a dry place).

So bought it anyway, I brought it home and I started to look at it more closely. I noticed that he did not remove the batteries from the MPU board, so they eventually leaked and apparently damaged a little bit the board, at least the U16 component (see pictures)

Before I noticed this, I tried to power the pinball machine on, and as expected it did not work at first. I only could see the DMD displaying "Bookkeeping Total Cleared - Factory Settings Restored" but nothing happened if I hit the Start button. However, after about 10 minutes it started to do a test cycle, play some music and the head of the bride started to move so I tried the Start button and, miracle, I could play a few balls, with music and light, the Machine wanted to come alive ! I powered it off and on again and was able to play a couple of time, but now it's stuck at "Factory Settings Restored" again, and when I try to enter test mode, nothing happens.

I noted during the boot that it is running L3 version of the ROM.

So the good news is that the pinball machine seems to work without major flaws, at least intermittently. The bad news is the battery leakage that I suspect is responsible for my problem.

I know I can change the board by a Rottendog WPC89 replacement board, but on the other had the damage on the original board seems little and I would like to get advise if this can be cleaned/fixed and how to proceed to avoid damaging it further.

Is it possible to clean a board with a product ? What is recommended to do in such cases ?

Thank you !

WPC89 MPU board detail (resized).jpgWPC89 MPU entire board (resized).png
#2 7 months ago
Quoted from aurelwap:

Is it possible to clean a board with a product ? What is recommended to do in such cases ?

Cleaning won't do it. Remove battery holder and all components below it. IC's, resistors, connector pins, everything.

Then neutralize, clean, repair, replace, drive yourself nuts.

Can be done. Is it worth it ?

LTG : )

#3 7 months ago
Quoted from LTG:

neutralize, clean, repair, replace, drive yourself nuts.
Can be done. Is it worth it ?

Thank you for your answer! So unless I really want to spend time on trying to replace all components let's say for an educational purpose, I'm better off purchasing a replacement board

#4 7 months ago
Quoted from aurelwap:

I'm better off purchasing a replacement board

Yes. The damage is more than what you circled and creeps along, even under the green mask.

I'd replace it.

LTG : )

#5 7 months ago

Adding to LTG's comments, look up the threads that discusses battery damage and Zep to get rid of any residue acid that's not apparent if you decide to try to repair.

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#6 7 months ago
Quoted from mbwalker:

Adding to LTG's comments, look up the threads that discusses battery damage and Zep to get rid of any residue acid that's not apparent if you decide to try to repair.[quoted image]

Doesn't vinegar accomplish the same task?

#7 7 months ago
Quoted from EvanDickson:

Doesn't vinegar accomplish the same task?

I thought there was a ratio of vinegar and water that works.

#8 7 months ago

I don't know your skill level but in all honesty ... that's not a repair job for a beginner / novice. Heck ... I'd even say it's not one for someone with some experience. You'll probably want a fair amount of board repair experience before attempting that.

If do try to repair don't try to salvage the ICs. Just cut the legs (as close to the body as possible) and replace the offending ICs after you've done all the alkaline abatement procedures.

That board can be repaired but it's not cost effective to pay someone to repair it.

#9 7 months ago
Quoted from EvanDickson:

Doesn't vinegar accomplish the same task?

From what I read, the Ph of vinegar isn't adequate (i.e. whimpy compared to Zep). From my failing memory, I think that was from one of Vid's restore threads. Search for 'battery damage' or 'battery acid' and go from there.

There's not a lot of complicated traces there like under IC's - just connections to resistors. But a lot depends on OP's experience.

#11 7 months ago
Quoted from Jjsmooth:

Just listen to LTG.

No doubt, regardless of my comments, LTG is a pro at this and wouldn't steer the OP wrong!

#12 7 months ago

Buy a new board, even if you neautralize it, the headaches and inconsistenies are not worth the time and effort. I stopped repairing these boards years ago.

#13 7 months ago

I fixed many board with even worst damage than this and from 4-5 years no one call me for problems with them.
But it's easy task.If you don't have experience in this better buy second hand clean board and this one may stay for parts or to practice.

#14 7 months ago

Good advice so far. It's not a monumental task, but one that takes some skill and the right tools. I've repaired a few with about that amount of damage, and they're still going strong 10+ years later. Some, I just did an acid wash to get the surface crud off, and left it alone, knowing that some day I'd have to possibly replace the board. If I were you, I'd go this route before immediately replacing the board. Take it off, give it a good ZEP/vinegar wash and scrub, and see if it fixes the problems. You might get lucky and get some serviceable time out of it. But it may fail again in the future, but you won't be any worse off if your plan was to replace it anyway. If you think you want to salvage it, and have it permanently repaired, then i would send it off for repair.

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