General advice on cleaning PCB

Thread Starter

DavidAlexander

Joined Sep 22, 2020
4
Hello all!

My name is David and I have a big problem and was hoping someone could offer some general advice about deep cleaning a corroded or oxidized PCB.

I have a heavy duty conveyor belt that worked perfectly fine until I let it sit outside during the rain season in California and it now powers on and the digital display comes on but doesn't send a signal to the motor. I opened the cover and it looks like there is some corrosion buildup. I read online that you can clean a corroded PCB by mixing 3 parts distilled water and 1 part baking soda into a slurry and letting it sit on the PCB for a few hours and then brushing and rinsing it off. I'm a bit concerned because I don't want to mess anything up or get electrocuted and was wondering if someone with a bit more knowledge than I could offer some very general advice.

I'm a metal worker by trade and have very limited knowledge about electronics (probably why I get zapped all the time) and apologize if I posted in the wrong form. :)

David
AnvilTools.US
 

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Thread Starter

DavidAlexander

Joined Sep 22, 2020
4
I guess my real question is would i be able to spray it with a PCB cleaner and rinse with with water without doing damage to it?
I will unplug it before doing anything but see that there is a 350v capacitor and don't want to hurt myself or the board.

Thanks,
Dave
 

narkeleptk

Joined Mar 11, 2019
474
I would start by replacing those lugs and hoping those wires are long enough to cut the tips off and find some less oxidized strands.
You can clean a lot of the dirt and metal salts with Isopropyl Alcohol pretty good but that wont help with the oxidation of the metals. The component legs I may would try a good flux and tin with solder, other then that I'd just leave as is if it tests good.
 

MrChips

Joined Oct 2, 2009
22,097
The board looks relatively clean. I would clean it with a small paint brush or toothbrush dipped in IPA.
Redo the wires going into the terminal block and replace the screws.

Once you have done the clean up and tested that it is fully functional, spray it with conformal coating.
 

Thread Starter

DavidAlexander

Joined Sep 22, 2020
4
There was enough slack to cut the wires back quite a bit and redo all the connections. I also took a wire brush to each terminal and screws until they were shiny and clean but for some reason it's still not working. The controller powers on and I can increase or decrease the rpm and it shows on the digital readout just fine but for some reason the motor won't turn.

Everything was perfectly ok before it sat outside during the last rain season and I haven't tried to turn it on until today. I am open to troubleshoot some more if anyone has any more ideas?

Thanks,
Dave
 
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