Repairing corroded pad traces on a remote control PCB

Thread Starter

joelgraff

Joined Dec 24, 2018
10
So I have an old remote control that's very hard to replace. It had batteries leak all over and the corrosion damaged a few traces quite badly. The remote keypad uses rubber domes to make the connections on the traces. I've been trying to imagine a way that I can repair the damaged traces without a lot of effort, but I really can't be sure it's possible.

Are there approaches to deal with this sort of problem?


IMG_0705.JPG
 

Thread Starter

joelgraff

Joined Dec 24, 2018
10
Are there any parts of the track completely missing?
The picture shows the majority of the damage. It appears as though the pads are largely missing for a few of them. I couldn't get continuity when I shorted them, anyway.

Replacing those pads is the thing I'm most concerned about...

Maybe scraping the PCB bare and using two thin strips of copper tape soldered back to good traces?
 

dl324

Joined Mar 30, 2015
11,282
Maybe scraping the PCB bare and using two thin strips of copper tape soldered back to good traces?
Clean the traces to see what you have to work with.

Some options for repair:
  1. Conductive (silver) epoxy
  2. Solder plating (if enough copper left)
  3. Adhesive backed copper tape
There's also some sort of lubricant/grease that can be used to help the buttons make better contact. My problem has been residue coming out of the buttons; cleaning up the residue fixed my remote. But not before I bought a replacement at Goodwill. I didn't want to break it trying to repair without having a replacement. Now I have two remotes.
 

jpanhalt

Joined Jan 18, 2008
10,095
You can get 2 oz. copper foil relatively cheaply (example: https://www.ebay.com/itm/COPPER-FOIL-2-oz-sf-6-x3-25-0-0028-2-8-mil-thickness-1-sheet-IRREGULAR/273786170251?hash=item3fbeed6b8b:g:fLIAAMXQ-BZQ9Sp~ ).

Cover one side. Print design on other side. Etch. The solder to what remains. You can also get silver nano-particle paint that is very conductive. Also, repair kits for rear-window defoggers may work.

There are two varieties of silver ink/paint. One is a vehicle (e.g., epoxy) filled with fine silver particles. The other is a silver compound that has no vehicle, and it deposits pure silver (conductivity about that of silver wire) after mild heating. The latter is more expensive.
 
Last edited:

bwilliams60

Joined Nov 18, 2012
1,332
On the extreme end you could build a new PCB board. Design it in KiCad or similar and have it manufactured cheap. Not sure how attached you are to that remote but learning something new can be fun.
 

Thread Starter

joelgraff

Joined Dec 24, 2018
10
On the extreme end you could build a new PCB board. Design it in KiCad or similar and have it manufactured cheap. Not sure how attached you are to that remote but learning something new can be fun.
I've considered the KiCAD route. I'm not good enough yet to feel like I can accomplish even a relatively simple design as this. But, it would be fun to try.
 

bwilliams60

Joined Nov 18, 2012
1,332
KiCad has a great forum with some really good people on there to help you through it. Digkey has tutorials on Youtube that are very helpful and there are a lot of people here on AAC that are knowledgeable with CAD design. If you have time on your hands, nothing lke the present to learn
 

Thread Starter

joelgraff

Joined Dec 24, 2018
10
KiCad has a great forum with some really good people on there to help you through it. Digkey has tutorials on Youtube that are very helpful and there are a lot of people here on AAC that are knowledgeable with CAD design. If you have time on your hands, nothing lke the present to learn
I've been doing the schematic for some old Apple IIe expansion boards, so I've been cutting my teeth on KiCAD. I'm not afraid of trying to doa PCB design, and I may if I can't repair this. But this seemed a good opportunity to figure out how to repair this sort of damage.
 

Thread Starter

joelgraff

Joined Dec 24, 2018
10
Having reviewed the suggestions and the options, I think I'm going to try getting a conductive pen off Amazon (a little more convenient solution than silver epoxy). The traces are 1 mm, which matches the tip, so I think it'll work. Opted for a nickel-based pen rather than silver as it's half the price and the lower conductivity is negligible here. There's a lot of missing traces to rebuild, though. Hopefully it goes well.

https://www.amazon.com/gp/product/B01LYAA814/ref=crt_ewc_title_dp_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER
 

bwilliams60

Joined Nov 18, 2012
1,332
If you Google PCB circuit board repair kits, there are a few companies that make some really nice repair kits for fixing traces etc. They are a little on the pricey side but probably a more permanent solution to your circuit board woes.
 
The gold looks really, really bad and I doubt it's repairable. The gold needs to be hard gold. You can buy adhesive copper, but I think you would need to plate it or coat it with a carbon based ink.

I just repaired three keyboards that had non-working buttons, but it was the elastomer that was worn. I used stuff called Conducto-lube. Expensive, silver mineral based stuff. It has lasted a month so far.

A friend just went through the exercise of re-building remotes. He lives in a salt water environment and thus he made a three-sided board to keep all of the traces between the top and the bottom.

I'll PM you concerning an option that may be available to you at a later time.
 
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