Removing water residue

Hardware MikroTik hardware general
1

Hi. My friend asked me “to check if his router is dead”. After disassembling it turned out that router has been watered at some point so badly that there’s water residue all over the board. Unfortunately router has been connected to power and only power LED was active all the time. It’s quite clear that it’s obviously not router failure (not waterproof RB951) but user error and that it’s almost lost cause. However if it doesn’t work anyways I don’t see any reason to not try to bring it back to life.

So I think I’ll start from removing that water residue. I tried with clear water but it doesn’t seem to help. Does anyone know any way of removing such residue without damaging board even more than it already is? My plan is:

  • remove residue
  • carefully dry it
  • try if it works
  • realize it doesn’t
  • solder out all valuable parts like capacitors and make them explode for lulz
  • throw it out with satisfaction that I did everything I could
2

There are PCB specific cleaning sprays with rust and damp proof/removal effect, most come with a cleaning brush attachment to ease application (be gentle rubbing!).

If water has been there, rust is your #1 enemy, as it could create shorts.

An easy method to “dehumidify” the PCB: put it inside an airtight container full of rice.

After a good cleaning, check for obvious shorts (rust) and related or damaged components.

3

You mean something like DeoxIT? I’m not sure how to google for such product.

4

I celan the boards with cellulosic thinner which ones are watered and be oxidized. if you can not find special spray for clean oxide you can use cellulosic thinner.

5

Google “PCB cleaning spray”, this is the one that is easily sourced in EU:

That being said, pure Isopropyl alcohol is equally useful, use a very soft toothbrush along with it to remove residues.

A pencil eraser is also handy to rub off rust, etc.

6

I think the dirty ionized water did what it had to do, shorted out something plus the board meanwhile corroded in some parts too and it’s done for.
You could fix it, replace the damaged components and clean it with ultrasound but it’s probably more cost effective to buy a new one.
This method is only reasonable if you have spare parts, tools, knowledge and experience at hand, otherwise the repair is going to cost you as much as a new board, perhaps even more.

I honestly hope it’s something easily fixable, and that you’ll make it but i doubt.
Anyhow, you could make before and after high resolution photos. :slight_smile:

7

Welp. I cleaned it but no luck so I gave up. Oh well at least I have some spare capacitors now xD