Cleaning PCB's with water damage - Page 1
Forum section: electronics / repair

author: iampoor
author_rank: Frequent Contributor
timestamp: November 12, 2017, 11:17:03 pm
content: HelloI am currently working on a rack mount power amplifier that has some water damage. Basically, the amplifier was used for an outdoor event, the sprinklers turned on, and sprayed the inside of the amp. Of course, an internal fan blew water everywhere.I have attached a picture of the worst damage, some components leads are starting to corrode, and some traces on the bottom of the board have major corrosion from water damage. I am not worried about fixing either of these issues. What I am not sure how to do (or where to start) is cleaning the water residue off the PCB's. Its hard to see in the picture but there is a thin layer of what appears to be dirt and other noticable areas of discoloration on the top of the board (Its a single sided PCB). It appears like the water has minerals or dirt in it, as you can very clearly see where the water sat on the PCB. Is there an industry standard procedure for cleaning water residue off PCB's? I would like to avoid any more corrosion on component leads.Of course, a google search only returns "repairs" for cellphones and the like. Sorry, its a too late to put this 80lb amplifier in a bag of rice.

author: schenkzoola
author_rank: Unknown
timestamp: November 12, 2017, 11:36:41 pm
content: First I would determine if any of the components on the board are sensitive to being submerged in water. This would be things like transformers, vented relays, and the like. If it can be submerged, I usually start by washing the board in the dishwasher. If it can't be submerged, I would probably spot clean with isopropyl alcohol and a toothbrush. No matter which method you use, I would then blow dry the board with compressed air, and let dry thoroughly in a warm place before powering.

author: Nusa
author_rank: Super Contributor
timestamp: November 12, 2017, 11:47:54 pm
content: I'd be willing to bet that the visible residue is mainly dust and lint that was on the board prior to being soaked, although the water will have moved it around. There wouldn't be that much junk in tap water, even in hard water areas.

author: schenkzoola
author_rank: Unknown
timestamp: November 12, 2017, 11:56:25 pm
content: Good point Nusa. It may be cleanable with compressed air only.

author: iampoor
author_rank: Frequent Contributor
timestamp: November 13, 2017, 12:33:23 am
content: Quote from: schenkzoola on November 12, 2017, 11:36:41 pmInteresting, thanks for the ideas!Quote from: Nusa on November 12, 2017, 11:47:54 pmThats what I was initially thinking, but I learned it was outdoor sprinkler water. The thing that confuses me is that the components that are corroded are upside down (The board hangs down from the top of the amp). SO maybe the corrosion isnt even water damage...I dont know with this one. There is always something new to be learned in repairing gear.The residue left behind reminds me of when I had to clean dog pee out of an amp, so it may just be dirt with lots of minerals in the water? Hmmm

author: David Hess
author_rank: Super Contributor
timestamp: November 13, 2017, 06:07:19 am
content: For large boards and assemblies which will not fit into my ultrasonic cleaner, I have used a power washer outside and then an air compressor to blow any remaining water out before drying outside in the sun.