View Full Version : Water and motherboard: Yea or Nay?

March 22nd, 2017, 12:06 PM
Opened up a recently-acquired 5160 IBM and was appalled at the amount of dust inside: more than I have ever seen in a machine. Vacuumed off what I could, stripped the components out and got down to the bare case. Washed the case but wondered (not for the first time) could I wash the motherboard?

Obviously if you had a paper capacitor that would not be a good idea. Everything here is tantalum so far as I can see.

Opinions? Not going anywhere until I hear from the experts.



March 22nd, 2017, 12:10 PM
You can probably wash it with little danger. Don't use soap, but a drop or two of dishwashing (not "dishwasher"!) detergent might help things a bit. Allow to dry thoroughly for a few days.

Generally, I find that a soft, damp (not wet) hog bristle paintbrush works pretty well without getting everything soaked. Damp so you don't kick up any static electricity.

March 22nd, 2017, 12:15 PM
You can blow and lightly brush enough dust off without water to get it clean enough.

Besides, if you use water on it and it fails to perform afterwards how you gonna feel?

While you can probably wash the board I'm of the school... if it ain't broken don't fix it.

March 22nd, 2017, 12:28 PM
You won't find any paper condensers in anything like that. If you did, you should replace them anyway. They don't tend to fill with water though; they are sealed with wax.

Water won't hurt anything if you make sure you let it dry. I have used Scrubbing Bubbles when I had something that really needed it. But, I always try compressed air first. If the dust comes off with that, you're set. Else, it has tobacco residue or industrial oil in it and you will need a surfactant.

Be mindful of paper labels, especially over EPROM windows. And other things which could come loose with air or water.

My rule of thumb is, if you think it's dry enough, put it in front of a fan for another night. There's no need to rush.

Whatever you do, don't use a pressure washer.

March 22nd, 2017, 12:33 PM
Whatever you do, don't use a pressure washer.


March 22nd, 2017, 12:39 PM

Wasn't that on this forum that someone posted pictures of doing that? Or I am I thinking of somewhere else? It too was a 5160, if memory serves.

March 22nd, 2017, 01:22 PM
Be mindful of paper labels, especially over EPROM windows.

Long time ago I was on a job where the R&D department was showing off their latest machine - computer controlled! Somebody took a flash picture of the innards and the thing stopped dead in its tracks. Demo over; custom EEPROM was left uncovered.

Whatever you do, don't use a pressure washer.

Oy! I've heard of people saying they pop the board in the dishwasher and run its cycle. The thought of that makes me nervous.

I'm talking warm water in the sink with a little dish liquid soap and some soft brush. Dry it with a paper towel and let it sit for a couple of days.

Thanks for the advice, guys / gals.


March 22nd, 2017, 01:31 PM
Use some forced air (a fan) to dry--water caught underneath components can stick around for a long time otherwise.

March 22nd, 2017, 01:52 PM
Warm water, dishwashing liquid and an old toothbrush are what I use to clean circuit boards. Compressed air helps to blow off the excess water, then I leave it in front of a fan to dry, and then I use a hairdryer on low to finish the job. You have to be careful not to let the board get too hot though, when using a hairdryer.

March 22nd, 2017, 02:06 PM
I use a cheap paintbrush with the bristles cut down a little (to make them stiffer) to remove stubborn dust. Actual filth or organic flux or whatever gets removed with soap and water. I use Dawn dish detergent (it's what we buy, other stuff is probably fine), hot water from the tap, and an old toothbrush.

For drying, I have an actual drying cabinet at this point (I do small batch assembly as part of my day-job), but before I had that, I just put the boards in the kitchen oven. Set it to the lowest setting (usually 170 *F or so) and leave the door ajar. When it beeps that it's up to temperature, it's done (about 10-15 minutes). Never killed a board this way.

March 22nd, 2017, 02:31 PM
I wash boards all the time with warm tap water and a small amount of liquid dish soap and use a fine soft brush while washing it to get rid of any dust. I let the boards air dry leaning on a glass block window in the basement for a few days. Just remove the BIOS chip, CPU, any kind of battery and all is good. If you live in a humid area make sure all the card slots are dry before powering it up (insert a card, remove it, check for moisture).

If you live in the mountains or get water from a mountain stream you will end up with a coat of calcium over everything so the final rinse should be with a jug of distilled water ($1ish).

March 23rd, 2017, 07:20 AM
I used Chuck's method. Thanks, Chuck, for the suggestion.


March 23rd, 2017, 07:45 AM
Recently i have acquired a computer that was full of mud and mean full to the last inch like it was buried in the earth. Cleaned it using hot water and detergent it was very oxidised have tu use a hard brush to clean it not easy also have to wash it using wd40 to get the rust. And after all of that it worked :D so in your case just let it dry well and it should survive.

March 23rd, 2017, 08:49 AM
My nightmare board was a printer PCB. It had been stored in a shed by the law firm that had used it.

Externally, it' looked absolutely cherry--even had all of the old manuals with it. Opening it up was a different story. Many generations of mice had called it their home--feces had deposited a concrete-like layer a half-inch thick over the board--and simple water wouldn't touch it. I eventually resorted to oven cleaner aerosol. It worked, but I don't know if it was worth the bother. You can't give away a daisywheel printer nowadays... :(

March 23rd, 2017, 12:51 PM
Something would have to be very rare and valuable for me to even think of messing with rat/mouse poop and even then I would probably say no. Could be worse and you could have cat pee inside, that stuff eats circuit boards and painted metal.

March 23rd, 2017, 01:01 PM
Yeah, that happened to me also. The cat is history.

March 23rd, 2017, 01:42 PM
Same here. Only professional audio gear is much more devastating to lose than personal computer peripherals.

I paid an arm and a kidney for a nice working daisy wheel printer a few years ago.

March 23rd, 2017, 01:56 PM
Got two: both Silver Reed; Japanese copies of the Olivetti line. Bought the first one in '83 along with a Kaypro II (my first computer; what did I know?) It's a typewriter with a serial / parallel interface (typewriter interface is card-edge serial and an intermediate box converts to parallel). As you might imagine, slow and clunky. I bought the second, which is a dedicated printer with a Centronics interface, out of frustration with the first, which is sheet-fed only. The second has a continuous forms adapter that works quite well. Of course by that time I had my own letterhead and switched to a Canon ink jet that was faster, quieter and more flexible in output.

Both daisies worked when I plugged them in early in 2106, though I had no idea they would be worth anything. Got extra ribbons and extra font wheels, too. Proportional spacing!


March 23rd, 2017, 02:09 PM
early in 2106

Man, that's old!

March 23rd, 2017, 02:35 PM
Inkjets killed the need for daisy wheel printers (back when lasers were too expensive).

I grew up with dot matrix printers so there is some nostalgia going on for me to have them now, but never had a daisy wheel printer.

I wonder if years from now there are going to be shops that detail circuit boards like people who detail cars do now. I mean you can't put a million dollar Apple 1 board behind glass if it is dusty (unless the dust was once part of Steve Jobs flaky skin with letters or authenticity from his dermatologists). ;)

March 23rd, 2017, 03:41 PM
Daisy wheels are still in use in places. My heating oil bill is printed by one. It's still good for letter quality carbon copies, wherever those are still required, if they really are.

March 23rd, 2017, 03:58 PM
Insurance agencies used them for a long time; multipart forms were their stock and trade.

I've still got a NEC Spinwriter and an Olivetti daisywheel that came with a 6300.

What really started taking a bite out of the daisywheels were the Japanese 21-wire dot matrix printheads. Some are NLQ multipass with downloadable fonts. Used with a film ribbon, it's hard to tell that they aren't daisywheels.

March 23rd, 2017, 04:15 PM
I've got a Spinwriter as well. But it hasn't seen much use because it has a sheetfeeder, which I never liked using. I've always hoped to find the pinwheel kit for it, but always forget to look for one.

March 23rd, 2017, 07:46 PM
Whatever you do, don't use a pressure washer.

Last time this topic came up I couldnt find the video I'd seen.

This time I did. (https://youtu.be/uguJu6h93y4?t=17m32s)

My favorite part: power washer throwing your cards off the concrete and onto the lawn? No problem! Just stand on them!

March 23rd, 2017, 08:09 PM
I note that the video is filed under "Comedy". About the only good thing that I can say is that he used a wimpy AC-powered washer, not one of the 20 HP gas-powered ones that could probably drill a hole in your driveway concrete, given enough time. One thing I learned with those is that you keep moving with it--it will easily drill holes in wood.

March 23rd, 2017, 08:20 PM
Two years later and I cringe at this video. I obviously had no idea what I was doing. I cannot recommend you power wash your boards as it is very rough on them. ... Also, don't remove a floppy cable with a screwdriver as it can only lead to damage.

He's actually posted a semi-recent (5 months ago) comment on that video that suggests it may be comedy now, but wasnt when he posted it. Fortunately, it didnt hurt anything, so the only thing it really cost him is a bit of embarrassment, and the paper label he lost during the power washer segment. He powers it on at the end of the video, so its mostly all good.