EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Zithen on May 05, 2014, 12:45:46 am
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I had seen some posts on cleaning boards with 91% (or so) isopropyl Alcohol and a few other things, but didn't know if that might be a good way to clean off dried up sugary drink?
I had gotten a arcade board and it looks like someone dumped a their cup of pepsi all over it and then it just sat there. I didn't know if using alcohol would be good to clean that out and if so do you just dump some on it brush it with a soft toothbrush then let it dry?
Watched several youtube videos on cleaning and they seemed to range in different ways, but didn't really know if what I was watching would be a good way or just what someone thought would be a good way. Any advice would be great.
Thanks
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A big tank of distilled or deionized water. Let it sit for a day, change the water, day, change, day change. Give it a good scrub with a non-static brush and cleaning mix of 10 parts water, 1 part isopropanol, and a bit of dish detergent. Then back into the water bath a couple of more times. Then a good rinse with pure isopropanol. Let it dry completely before powering it up.
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One thing to look for after you have the crud cleaned off it is whether the acids in the drink ate any of the traces, component leads and that kind of thing. Use a good magnifying glass to spot problems before powering it up. This will give you a chance to reeconnect things if needed. Pepsi, Coke and other products often have phosphoric acid in them which, over time, can really wreak havoc...
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A big tank of distilled or deionized water. Let it sit for a day, change the water, day, change, day change. Give it a good scrub with a non-static brush and cleaning mix of 10 parts water, 1 part isopropanol, and a bit of dish detergent. Then back into the water bath a couple of more times. Then a good rinse with pure isopropanol. Let it dry completely before powering it up.
with soaking it do I need to worry about the removable eproms? I am guessing know, but just don't know if the little glass window is water proof or not.
One thing to look for after you have the crud cleaned off it is whether the acids in the drink ate any of the traces, component leads and that kind of thing. Use a good magnifying glass to spot problems before powering it up. This will give you a chance to reeconnect things if needed. Pepsi, Coke and other products often have phosphoric acid in them which, over time, can really wreak havoc...
That is one thing I hope hasn't done to much damage and hoping for no damage. If it has the good side it was free, the bad side is that its Teenage Mutant Ninja Turtles. That game was fun ;D
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It should go without saying that you should remove all socketed components first.
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I just wash boards in the kitchen sink using tap warm water and detergent then shake off excess water and rinse immediately in alchohol and dry in warm air either the airing cupboard or a hair dryer depending on how fast I want the board.
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I clean boards by just running them through the dishwasher. As soon as it's finished, pull the board out and rinse with distilled water. Allow to air dry for about a week, then bake for a couple of hours at around 175F (around 80C).
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It should go without saying that you should remove all socketed components first.
I had thought as much, but just wanted to make sure.
Thanks for all the suggestions.
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I clean boards by just running them through the dishwasher.
That's kind of terrifying, actually :o
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Not really, a lot of PCB assembly houses use a regular dishwasher to get flux residue off the boards. they just use a warm oven as well afterwards to get the last of the water out.
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I clean boards by just running them through the dishwasher.
That's kind of terrifying, actually :o
I've used the technique to clean computer keyboards... especially older IBM clicky board with the removable key caps (those sucker are actually pretty hard to kill)
rules
#1: Don't use soap
#2: Don't use the dry cycle
#3: Make sure you let it completely dry
#4: hard way, if removing the key caps, put them in a cheese cloth bag and not just the cutlery thing. They get everywhere <G>
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Had a "friend?" spill a "screwdriver" into my Korg Trident ( showing my age?)
A real PITA, but washed it out with water, then a rinse with distilled water..carefully (not fun)..use a lab wash bottle..
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Distilled or Deionized water.
I've used tap water in an emergency: my wife's laptop got drenched by a sugary drink. I immediately popped the battery out, ran to the sink and turned the tap on full blast letting water run out the cooling louvers. I shook most of the water out then let it sit in the window to get some warm sun (it was winter...no going outside in Ohio). Waited ONE DAY and powered it up. Not even a hiccup. ;)
YMMV.
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Coke ... sugar ... food ... and already dried-up ... this little helper removes anything:
http://de.farnell.com/kontakt-chemie/kontakt-lr-400-ml/leiterplattenreiniger-400ml/dp/3047453 (http://de.farnell.com/kontakt-chemie/kontakt-lr-400-ml/leiterplattenreiniger-400ml/dp/3047453)
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I clean boards by just running them through the dishwasher.
That's kind of terrifying, actually :o
I've seen commercial contract manufacturers who routinely clean all of their production PCBs this way. Works quite well actually. They'll use purified water for it, but you can get away with using normal tap water as long as you rinse with clean water before they dry.
I've also heard of people using "Jet-dry" in the dishwasher to prevent mineral deposits from tap water. The tradeoff is that it coats them with a thin layer of silicon, which makes them hell to solder after (so don't clean until all hand-soldering is completed). The silicon can be cleaned off with Acetone if needed for rework after washing.
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Put under water indstead ^-^
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Just took the board out from the first day of soak. That was nastiest thing I have seen in a while.
It's looking good so far. The parts that have cleaned up so far don't look to bad. Hopefully after another soak the more covered section will clear up and be able to see what damage was caused by the soda.
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Pictures?
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I will second the 'warm water and detergent' procedure- For many decades I augmented my pay by repairing CRT TVs, going way back to Philips G8s etc. I always cleaned the crud and nicotine from the PCB with hot water and Fairy liquid using a soft paintbrush, followed by a de-ion water rinse and a week to dry above a heating radiator, or later a dehumidifier. I must have done many dozens like this and never a problem with the EHT etc. Not too many worries about ESD in those days, but I have done this recently to clear tea from a Dell laptop, and mud in a HDD recorder and have not had a problem.
Regards, BT
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There's a pretty good chance the pop's carbonic acid (CO2 in solution) had a chance to do some eating.
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Pictures?
I am a terrible person because I didn't take any pictures. I was actually thinking about that when I was doing a final cleaning of the board early this morning. |O
I don't think the drink was on there as long as I was told or the board was amazingly durable. It was dried on there pretty good, but after the first soak and brushing it come off pretty good with some areas still bad. After another soak and brushing there wasn't really anything left. After another short soak and cleanup you really can't tell anything was on it expect a few sticky spots on the top of the eproms.
Right now it's drying and hopefully later tonight or tomorrow morning will boot it up and see if it works.
There is only one place that looks like it might be a problem and that is between two pins of a chip it looks like the they expanded or something and cracked a little bit of the board. The bad thing is there is two traces that go through that spot. Once it dries that is the first thing I need to check. Other then that you can't even tell it had something on it.
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well the stuff that is left when soda dries up is still the stuff that's designed to be water soluble. It shouldn't be a big deal to remove.
you can tell the age, usually, by the amount of dust that is stuck to the syrup. not a lot of dust = not a lot of time.
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Looked the board over and only just that one spot that looks bad. Tested the pins next to the area and the two traces that go through that spot and seems ok according to the continuity. Turned the game on the game actually works...kind of. The only issue is that there is some audio issues, mainly with the voice audio. Just so happens that chip is in the voice diagram.
Haven't worked on a board issue like this, but just mean time to learn new stuff ;D
(http://i57.tinypic.com/2vsp99e.jpg)
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Time to unsolder that chip and clean up and repair the 2-5 through hole vias under it that are now high resistance. When you have the chip out place a 28 pin turned socket in there, and put the chip into another 28 pin turned socket so you can remove it later if needed.
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Time to unsolder that chip and clean up and repair the 2-5 through hole vias under it that are now high resistance. When you have the chip out place a 28 pin turned socket in there, and put the chip into another 28 pin turned socket so you can remove it later if needed.
I was wondering what you would do to repair the through hole vias (sorry just a bit new to board work). The cracking or what not that is there between the pins seems to be only on the top layer. There is nothing showing through on the bottom side.
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First remove the chip, and then clean the board under it. Then gently remove the solder mask both top and bottom ( and in this case likely the tracks as well) to bare copper, flux lightly with liquid flux, and use a strand of tinned copper wire through the hole soldered top and bottom to remake the via. then clean the board again and apply a protective coat of clear varnish ( clear nail varnish is good for this, as it is not readily visible, and it is not really available in PCB green) to protect. Then solder in an IC socket and replace the chip after cleaning the board again with IPA. Take the pins on the IC and straighten them and use solder wick to remove excess solder.
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Looks like someone has reflowed a few pins already. It's hard to see from the picture but if you believe those two tracks are ok and the via to the pins are also ok. I would add flux on top and underneath and then reflow the pins with a touch of leaded solder with your iron from the underside. Then clean and retest the board. Just don't over work that area too much that's all.
On these old boards reflowing them is sometimes needed to get the chip out easily as well.
If you cannot get good wetting to the top of the eyelets it means they are too corroded (or your didn't clean enough).
A proper clean and inspect will require the chip out and you will always want to socket it as SeanB mentioned.
I personally don't remove things until I've ruled out bad joints.
Additionally if you haven't removed solder mask off a via or track before or soldered to one this is a challenge in itself.
As it's delicate work I would practice on an old board first.
Watch the complete series of the Pace repair and rework videos they are excellent. They cover the important techniques of cleaning, flux and tinning. https://www.youtube.com/user/paceworldwide (https://www.youtube.com/user/paceworldwide)