Cleaning and Repairing Battery Corrosion on a PCB

[RukyCon]

Hello, So i'm helping repair a board that has suffered what appears to minor battery corrosion on a battery holder contact and possibly a 16pin chip directly below the said contact.

I can't remember what the board number was but it's the motherboard to a Williams pinball machine (or at least it contains the CPU, ROM, and RAM chips).

As far as i can tell, the damage seems to be isolated to the terminal and the IC.

I'm looking for some input on what i should do as my current plan was to desolder the battery holder, clean off at least half the PCB (so i don't have to remove the ROM and CPU chips), and install a new (external) battery holder.

As of right now, the board does, for the most part, work but the battery-backed RAM will randomly lose its memory when the machine is shut off.

I'm sorry if the photos are a bit blurry, it was the best i could do at the time and i will try do get better photos in a few days or so.

Note: the bubbly thick traces on the bottom side of the board seem to be a factory defect as at least 2 of the 3 boards in the back of the machine seemed to have that issue.

[PKTKS]

In your local area (US ?)  I would not think twice.

BRANSON OR  solutions  after a mild IPA mechanical brush..

https://www.all-spec.com/Catalog/Chemicals-Cleaning-Supplies/Ultrasonic-Cleaners-Accessories/Ultrasonic-Cleaner-Solutions/000-955-516-6768

Check also
https://www.eevblog.com/forum/repair/removing-oxidation-from-plated-through-holes/

Paul

[ArthurDent]

Forget the bubbly look to the traces, that is normal. On alkaline battery crud I have used white vinegar to help neutralize the base while using a brush and tooth picks to get as much under the IC pins as possible. I would carefully remove the battery holder because it will be hard to get rid of any crud under there otherwise. Unless there are any fine traces under the battery holder they are probably o.k. and haven't been ruined. The green resist on the board probably has protected most of the runs.

After a good cleaning I have used soap and water then a good rinse to  clean the board then totally dry the board for longer than you'd think is necessary before reconnecting it in a circuit. I have used my oven set below 150 degree F to speed the drying as well.

Keep in mind this has worked for me but you're on your own deciding whether you want to try this or not. It is important to neutralize the crud to stop any further chemical reaction and remove the conductive runs the crud has formed.