New! Dark mode!

Browsing Pinside at night? Getting tired of all the white? Switch to dark mode using the button in the top right (or CTRL-B)!

(Topic ID: 169335)

Is this your typical alkaline corrosion?


By koen12344

4 years ago



Topic Stats

  • 12 posts
  • 8 Pinsiders participating
  • Latest reply 4 years ago by koen12344
  • No one calls this topic a favorite

You

Linked Games

Topic Gallery

There have been 15 images uploaded to this topic. (View topic image gallery).

IMG_6655 (resized).JPG
IMG_6653 (resized).JPG
IMG_6654 (resized).JPG
IMG_6652 (resized).JPG
IMG_6650 (resized).JPG
IMG_6649 (resized).JPG
IMG_6648 (resized).JPG
IMG_6646 (resized).JPG
IMG_6647 (resized).JPG
IMG_6645 (resized).JPG
IMG_6644 (resized).JPG
IMG_6643 (resized).JPG
IMG_6641 (resized).JPG
IMG_6642 (resized).JPG
IMG_6656 (resized).JPG

#1 4 years ago

Hi guys,

I'm repairing a Dolly Parton, which has stood uncovered in an open shed for the past 16 years.

After some preventive maintenance and fixes I got the game going without any major issues. One of the feature lights wasn't working and the 5101 socket is a bit flaky. I went to troubleshoot the light issue and was in for a nasty corrosion surprise on the back of the lamp driver board.

I took out the battery a while ago and it hadn't leaked if I remember correctly. I'm starting to question that now since there is some corrosion near where the battery once was (see R134, R29, and the capacitor next to R23). But the worst damage seems to be near the mounting brackets and screws on both boards?

I have dealt with alkaline corrosion in the past, but nothing like this. I believe these boards have a NiCad battery on them, is it the same procedure? Did this even get caused by the battery? Hope someone can point me in the right direction on how to proceed with this one.

#2 4 years ago

Images did not upload... Trying again here

IMG_6656 (resized).JPG

IMG_6642 (resized).JPG

IMG_6641 (resized).JPG

IMG_6643 (resized).JPG

IMG_6644 (resized).JPG

IMG_6645 (resized).JPG

IMG_6647 (resized).JPG

IMG_6646 (resized).JPG

IMG_6648 (resized).JPG

IMG_6649 (resized).JPG

IMG_6650 (resized).JPG

IMG_6652 (resized).JPG

IMG_6654 (resized).JPG

IMG_6653 (resized).JPG

IMG_6655 (resized).JPG

#3 4 years ago

"has stood uncovered in an open shed for the past 16 years"

I think this is some if not most of your problem. Look for corrosion under the playfield. Some of the corrosion around the battery holder may have been left over from a old battery.

#4 4 years ago

The lockdownbar holder and transformer mounting bracket have some corrosion on them, but they're by far not as bad. Actually the machine is in pretty good shape considering the situation.

Maybe a previous tech has replaced a corrosion-damaged MPU at some point and didn't bother to clean/replace the mounting brackets, screws and check the lamp driver?

The damage on the lamp driver board is towards the mounting bracket, and not below the battery. The component side is totally clean.

#5 4 years ago

Could it also be some "galvanic" corrosion, with steel screws and Aluminum plate?

#6 4 years ago
Quoted from thepinballworks:

"has stood uncovered in an open shed for the past 16 years"
I think this is some if not most of your problem. Look for corrosion under the playfield. Some of the corrosion around the battery holder may have been left over from a old battery.

Maybe someone cut the old nicad off and installed a remote battery holder and tied it to that corner of the board, then cut it off when it corroded.

#7 4 years ago

The strange thing is, the corrosion is also on the mounting screw on the top right corner of the MPU. I was also leaning towards galvanic corrosion, but you'd think it would be all over the backbox.

Maybe "its the best of both worlds"?

Edit: to add, i've tried putting some vinegar on the affected metal brackets (not on the PCB's yet), to see if it would have any effect, and it does seem to clean it up a bit over time, but without the satisfying hissing sound you normally get

#8 4 years ago

There looks to be some NiCad corrosion in the reset area near the battery (old Bally/Sterns used NiCad batteries) Typically the traces show a lot of eating away and all the components have to be removed, board sanded etc... - this one not as much. I venture to say most of the rest away from this area, such as the board mounting screws, is moisture related from the storage conditions

Neutralize the board corrosion as best possible using white vinegar, followed with a cleanup rinse of 91% isopropyl alcohol. Since the game boots you might get away with not replacing the components if the corrosion process has not penetrated the component bodies. I'd try some other rust remover, like Naval Jelly on the metal backboard and mounts and replace all the rusted screws for for board and cable mounting.

#9 4 years ago

I would replace that 5101 socket on the MPU, brush off that light corrosion on top, throw that lamp driver board away, order a new lamp driver board, and you're good to go. Corrosion on that MPU is VERY light.

#10 4 years ago

You've also got green/corrosion on the J4 pin connector of the MPU board and probably in the J4 cable connector too.
So you'll need to replace the MPU J4 pin header and re-pin that cable connector too.

#11 4 years ago

Yeh, clean up that corrosion on the board mounting brackets. What I do is use a good wire brush to get most of the corrosion off, then soak in C-L-R (50% water and 50% C-L-R) solution and scrub again with the wire brush. Rinse the part with warm water. Now spray with Mean Green (or other household cleaner like 409 or Fantastik) and rinse again. That final spray of the household cleaner halts all of the C-L-R action. You can now either tumble the bracket or polish it with Brasso or Simichrome. A nice clean, shiny bracket will now have a good ground connection to the board.

#12 4 years ago

Thanks for the solid advice everyone, I'm confident i can fix the issues with the MPU and mounting brackets in a decent way now.

I'm not yet sure what I'm going to do with the lamp driver. It's magically fully working right now apart from a broken scr...

Promoted items from the Pinside Marketplace
From: $ 15.00
From: $ 14.00
Electronics
Third Coast Pinball
From: $ 45.00
Displays
PinballSolutions.eu
From: $ 155.00
$ 119.95
Boards
Allteksystems
$ 9.00
Electronics
Yorktown Arcade Supply
$ 11.00
Electronics
Third Coast Pinball
From: $ 18.00
Apparel - Men
Pinside Shop
$ 22.50
$ 149.95
Boards
Allteksystems
$ 49.99
Electronics
PinballElectronics.com
From: $ 140.00
$ 149.00
From: $ 25.00
Boards
nvram.weebly.com

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside