Muff's Modules & More

chriscoady

Hey guys,
If I wash a pcb with an IC socket could the water cause rusting or oxidation that could interfere with the contacts down the road?

Also if the trim pots are already on there will washing the pcb mess them up too? I am guessing they are sealed....

Thanks in advance for any info!

Best,
Chris

noiseboss · Posted: Sun Apr 01, 2012 7:08 pm Post subject:

i've heard of some old guy servicing some vintage gear (roland, moog, whatever) using his dishwasher.

second hand account.

CJ Miller · Posted: Sun Apr 01, 2012 7:46 pm Post subject:

MOST parts are fairly safe to wash, but there are exceptions. Sockets should certainly be fine, but it is crucial to make certain that they are completely dry before plugging in ICs or applying power. Delicate and expensive parts like polystyrene caps and vactrols I do not wash. I install resistors, caps, diodes, transistors, sockets - then wash - and install the remaining parts later with no-clean solder.

Pots being "sealed" just means that they are not open-frame. They still have moving parts, and they are not truly encapsulated. Detergent thins water significantly... how much of it could travel down a pot shaft into the unit? I don't know, and I'd rather not find out. Trimpots would be especially susceptible. If I needed to, I'd spot clean around them with a toothbrush, but not submerge or machine wash.

Detergent for automatic dishwasher machines is typically formulated to leave no residues, which is a good thing. My preferred solution is 90%+ alcohol, which is also residue-free. But again, I keep it off of delicate of moving parts.

chriscoady · Posted: Mon Apr 02, 2012 1:03 am Post subject:

Thanks for the info!
Was just about to put 3 polystyrene caps in this board and glad i read this first.

i have been doing everything on the pcb with the normal solder and switching to no clean solder when panelling.

When you are washing the boards you run it under room temperature water in the sink and scrub with a scrubber until you get to the trimpots stage and then you switch to cleaning around them with a wet toothbrush?

Thanks again guys,
Chris

gwaidan · Posted: Mon Apr 02, 2012 1:44 am Post subject:

I would suggest you study the datasheets for the trimpots carefully first-if you can't get confirmation that they are washable then use no-clean solder on them. Remember these are mechanical devices and moisture that gets into them may be hard to get out...

Dave Kendall · Posted: Mon Apr 02, 2012 3:53 am Post subject:

If you live in a chalky area, tap water can leave a dirty white residue. Surprising how much effect it can have. First time it happened, I thought the board had gone mouldy! (not really... wink

) Cheap bottled water - you don't need distilled - works fine for a final clean-up if you have manky mains water.

After clean-up, I usually leave the board in the airing cupboard where the hot-water-boiler is for 20 mins or so after washing. It's definitely nice and dry then .....

cheers,
Dave

J3RK · Posted: Mon Apr 02, 2012 1:13 pm Post subject:

I wash/rinse anything but trimpots generally. Anything with a moving part or enclosure that could trap water/minerals/etc. I would put on the board with no-clean solder after washing the board.

pugix · Posted: Mon Apr 02, 2012 3:32 pm Post subject:

The parts I leave for no-clean solder are: trimpots, polystyrene caps, anything that needs thermal compound applied, like tempco resistors. As for the polystyrene caps, they may be sealed, but since their leads are so thin, I'm worried about damage from the toothbrush I use to scrub with.

I also use the final rinse with distilled water. This is recommended by John Blacet, too.