• Please review our updated Terms and Rules here

Damaged ISA Card - How could I go about repairing it?

ButINeededThatName

Experienced Member
Joined
Nov 29, 2018
Messages
176
Location
Fort Wayne, IN
So I have a Persyst Time Spectrum 384L that had it's Varta barrel battery spew acid all over the board. After soaking it in vinegar for about eight hours I did manage to get all of the corrosion off, however I came to the realization that about a quarter of the RAM sockets and two sockets for logic chips had lost pins.

IMG_20211004_092502.jpg
IMG_20211004_092515.jpg

I'm trying to figure out where to go next. I really like this particular model of board, however I'm also wondering if it's even worth trying to repair it from here.
 
Yeah, I wouldn't tackle that card without a desoldering station/gun. You'll definitely want to remove all of those sockets and replace them, especially if you soaked the entire board in vinegar for 8 hours, because that wasn't a good idea. You'll probably have to start replacing ICs and passive components as well from the vinegar damage. Since the vinegar stripped the plating and damaged the metal legs, you're going to start having corrosion issues later on. There was no reason to soak it for 8 hours, that is FAR too long. You should have only gotten the affected areas of the board the vinegar treatment, and no more than 10-15 minutes. Acid-base reactions take no more than a few seconds, and the stuff hiding under chips no more than a few minutes. Anything worse than that, like eaten traces need to be done manually.

I also see some trace damage under where the battery leaked. You'll need to remove the components along the trace to inspect all of it for breaks and severe damage that alters the conductivity of the copper.

The card is probably repairable, but you made a lot more work for yourself with the misguided vinegar bath. It's going to take a lot of time and money to fix that card, so you'll have to make the decision if it's worth it or not.
 
I don't think those DIP switches are sealed types, so they will have got the vinegar in them too and will require replacing.

Leaked electrolyte from batteries or capacitors can be difficult to remove, it is ionic, conductive and not soluble in contact cleaners and it can even infiltrate the green conformal coating creating a thin conductive blanket on the surface.

It might be possible to save the board. All the IC sockets should be removed and the DIP switches too and discarded. The board could be placed in a bath of deionized water for a day to leach out the ions, and then done again in a fresh bath. You could raise the bath temperature to 40 degC to speed the process up, but no hotter to be safe.

Then clean and inspect the board for track damage and check every plated through hole and repair where necessary. If a plated through hole is corroded, the better move is to drill it out and replace it with a link wire. If it is a 4 sided board, where you cannot access both sides of the plated through hole, it may well be "game over"
 
Last edited:
Back
Top