On Wednesday, October 1, 2014 8:34:03 PM UTC-4, Phil Allison wrote:

However, some example are so badly fouled the only way I have found to clean them properly is to submerge the PCB and heatsink assemblies in hot water and detergent and scrub them just like dinner plates and saucepans. In order to thoroughly dry the PCBs, I have used an oven set to low temp, hot air from a room heater or gun and simply the sun on a warm day.

Back in the late 70s when TVs had large,hot running modules and it seemed like everyone smoked, I used to wash these boards before rebuilding them.

What I would do is remove any component that could trap water, such as flybacks, smps xfrs, large inductors, tuning coils, tuner, etc. then wash the board in the sink with hot water and a cleaning solution my brother (research chemist) used to make for me by the gallon. It was also great stuff to clean white walled tires with (some kind of detergent and stoddard solvent mixture).

I would let them drip dry, then put them in a large cardboard box with a hole in one end the diameter of a hair dryer, and let the board dry for an hour or so. I'd clean by hand the parts I had previously removed and reinstall them in the board then repair or rebuild the board as needed. The modules were squeaky clean and shiny. There was NEVER an issue with submerging the boards in water, and I did not rinse them with anything more than tap water.