Cleaning a very very dirty disgusting PCB ..  - Page 1
Forum section: electronics / beginners

author: andrewwong2000
author_rank: Contributor
timestamp: July 01, 2014, 12:55:08 pm
content: Turns out some cats have been sitting on top of, and occasionally spewing into this el-cheapo Sherwood home theatre receiver,and look to have blown the voltage regulators..Any suggestions on what solvent I can safely use to clean the PCB and gunk ? Would IPA be a good starting point ?Tempted to desolder the tuner, then try and fit this into my 9L ultrasonic cleaner.. with some detergent

author: Stonent
author_rank: Super Contributor
timestamp: July 01, 2014, 01:11:17 pm
content: I'd start with a vacuum or an air hose to remove the fluff. Followed by alcohol and a toothbrush to remove the other nastiness. Once clean I might consider some clear lacquer or nail polish on the areas that had some corrosion if the connections are still good to delay any further damage.

author: kolonelkadat
author_rank: Regular Contributor
timestamp: July 01, 2014, 01:48:05 pm
content: i came here expecting to say "dishwasher " but then I saw the boardid say the best way to clean it is to wrap it in plastic and place it directly into the nearest trash can

author: KJDS
author_rank: Super Contributor
timestamp: July 01, 2014, 02:01:51 pm
content: bin it, buy a new one.

author: sfiber
author_rank: Regular Contributor
timestamp: July 01, 2014, 02:04:38 pm
content: you just remove everything that you think its work,then throw away this circuit to main trash immediately.

author: XOIIO
author_rank: Super Contributor
timestamp: July 01, 2014, 02:17:38 pm
content: Quote from: kolonelkadat on July 01, 2014, 01:48:05 pmMan, no kidding. This isn't worth it.

author: jlmoon
author_rank: Unknown
timestamp: July 01, 2014, 02:19:39 pm
content: Carwash for that one..ehhh.. second thought after seeing the corrosion,, trash it!!!

author: dfmischler
author_rank: Frequent Contributor
timestamp: July 01, 2014, 02:29:36 pm
content: Must agree with Stonent about starting with compressed air *outdoors*. Do not breathe any of that crap. That will at least let you see the extent of the damage. It might be repairable in the short term, but it might not be possible to stop the continuing corrosion.

author: janoc
author_rank: Super Contributor
timestamp: July 01, 2014, 02:56:40 pm
content: Guys, that shouldn't be repaired, that should go straight to hazardous waste. And don't forget your hazmat suit when handling it.Really not worth repairing, IMO.

author: Rasz
author_rank: Super Contributor
timestamp: July 01, 2014, 03:50:51 pm
content: Im pretty hardcore, but even I wouldnt bother. Its not like its 35 year old vintage computer.

author: grumpydoc
author_rank: Super Contributor
timestamp: July 01, 2014, 04:22:23 pm
content: Oh FFS can you lot man up? - do none of you own cats? Clearing up puke goes with the territoryRemoving the furballs and dried on gunk would be a good first step, followed by plenty of water - the gunk should be pretty water soluable but obviously you're rehydrating dried cat puke at that point.However cat puke is presumably acid and it looks as though it has attacked the PCB traces so itisprobably BER.

author: rob77
author_rank: Super Contributor
timestamp: July 01, 2014, 04:58:13 pm
content: just go ahead with the ultrasonic + water with detergent... it can't be worse.... and even if.... i'd rather troubleshoot a nice clean boardafter the water, go ahead with a pure IPA and dry with compressed air (or hot-air with lowest temp possible).

author: XOIIO
author_rank: Super Contributor
timestamp: July 01, 2014, 06:04:51 pm
content: Quote from: grumpydoc on July 01, 2014, 04:22:23 pmI don't think it's the cat's puke....

author: rob77
author_rank: Super Contributor
timestamp: July 01, 2014, 06:11:14 pm
content: Quote from: XOIIO on July 01, 2014, 06:04:51 pmno, it's not only cat's puke... it's everything a cat can ever produce mixed together...just give it long dip in the ultrasonic cleaner... end probably even give it a nice splash with a garden hose first

author: XOIIO
author_rank: Super Contributor
timestamp: July 01, 2014, 06:14:52 pm
content: Quote from: rob77 on July 01, 2014, 06:11:14 pmNo, but from the wording of the post I think the previous owner might have... contributed to the collection.

author: Bored@Work
author_rank: Super Contributor
timestamp: July 01, 2014, 07:39:50 pm
content: Industrial strength pressure washer. Outside, of course. Direct the water jet in the general direction of the neighbor you like the least.Parts blown off or blown to pieces aren't worth it.

author: rob77
author_rank: Super Contributor
timestamp: July 01, 2014, 07:56:19 pm
content: Quote from: Bored@Work on July 01, 2014, 07:39:50 pmcrank up the pressure really high - blow away everything (including all the boards - the neighbor might appreciate the spare parts for free) then stuff some old rags into the cleaned case and give it back to the cats

author: Shock
author_rank: Super Contributor
timestamp: July 01, 2014, 08:16:04 pm
content: It's not as much mess that mice make when they discover the SMPS.Especially when their decaying corpses have been left for months.Don't as others have suggested vacuum that shit unless you want to breath particles of it every time you vacuum.It looks totally repairable as it's a one sided board.What I would do is put on gloves and a mask and then remove that whole board.Soak the board in a bucket for a while and then rub and scrub off most of the crap.When you get it clean enough take photos and depopulate the parts with corrosion.Then you can work with abrasives if you really need to and test the components.Clean the lightly soiled boards with a brush and alcohol or detergent and rinse well.You need scrub everything in the box with detergent really well, when it heats up you will smell cat."if it comes home with you it's a keeper"

author: rob77
author_rank: Super Contributor
timestamp: July 01, 2014, 08:24:22 pm
content: Quote from: Shock on July 01, 2014, 08:16:04 pmhe mentioned he has access to a ultrasonic cleaner - no need to manually clean. it's just a matter of a right amount of detergent and let it shake off the mess

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 02, 2014, 04:28:55 am
content: Repairability: sadly, being one sided -- and the solder side still looking pretty darn good, actually -- I'm sure it's fully repairable.But, why?..Even after cleaning off all the biohazard, you've got partially eaten-through leads. You'll be plagued by electrolytes soaked into the crevices between pins and components. Electrolytic caps will likely fall off with a gentle wiggle, or give up years later. You can replace all the jumpers, easy enough, but a tedious pain -- but what about the resistors and capacitors and transistors? Do you have replacements for all of them? Can you inspect them well enough to be confident it's worth it?Tim

author: andrewwong2000
author_rank: Contributor
timestamp: July 02, 2014, 01:41:16 pm
content: Just for fun... a bit of time in the ultrasonic and detergent..Looks worth plugging in now

author: rob77
author_rank: Super Contributor
timestamp: July 02, 2014, 04:09:23 pm
content: is that a corrosion or just some remaining mess around the jumper wires ? if it's still a mess , then i would give it another go in the ultrasonic with even more detergentbtw.. it looks really much much better now

author: XOIIO
author_rank: Super Contributor
timestamp: July 02, 2014, 05:58:08 pm
content: Holy shitI need an ultrasonic cleaner!

author: rob77
author_rank: Super Contributor
timestamp: July 02, 2014, 06:20:00 pm
content: Quote from: XOIIO on July 02, 2014, 05:58:08 pmthose are expensive - especially the industrial grade ones. but you can buy a cheap one as well , but those are rather small - you wouldn't be able to fit that board into small & cheap cleaner.

author: Shock
author_rank: Super Contributor
timestamp: July 02, 2014, 07:14:37 pm
content: Quote from: rob77 on July 01, 2014, 08:24:22 pmI missed that, but I would still give have given it the bucket before I put it into the cleaner that crap was nasty.

author: rob77
author_rank: Super Contributor
timestamp: July 02, 2014, 07:21:16 pm
content: Quote from: Shock on July 02, 2014, 07:14:37 pmi suggested to splash it with a garden hose firstbut anyways... even if pre-cleaned you have to replace the water in the cleaner immediately after such a mess. (usually you replace the water after several cleaning jobs).

author: sunnyhighway
author_rank: Frequent Contributor
timestamp: July 02, 2014, 09:40:50 pm
content: Quote from: XOIIO on July 02, 2014, 05:58:08 pmI'm afraid that won't work very well.Removing Holy Shit would typically require a Dirt Devil.

author: Riotpack
author_rank: Regular Contributor
timestamp: July 02, 2014, 11:11:35 pm
content: ARC furnace for 24 Hours should clean it nicely

author: Spikesta
author_rank: Newbie
timestamp: October 03, 2014, 08:18:06 am
content: Hi guys n girlsI need some help repairing a ultrasonic cleaner . Im not sure where to post my topic as i am new to the forumplease could you point me in the right direction.RegardsSpikesta

author: ResR
author_rank: Regular Contributor
timestamp: October 03, 2014, 08:46:33 am
content: I'm impressed how clean the board is after all that gunk. I would classify this as unrepairable and hazardous material like asbestos, but the result after ultrasonic bath is impressive. The corrosion residue on board between the jumper wires probably merged into the PCB material itself so it shouldn't be a problem for few years.Of course the arc furnace is the best method for cleaning PCB's, thumbs up to Riotpack.

author: tautech
author_rank: Super Contributor
timestamp: October 03, 2014, 10:11:24 am
content: Quote from: Spikesta on October 03, 2014, 08:18:06 amWelcome to the forumSpikestaOpen a new topic in Repair.https://www.eevblog.com/forum/repair/

author: Zeta
author_rank: Contributor
timestamp: October 03, 2014, 03:48:19 pm
content: Quote from: kolonelkadat on July 01, 2014, 01:48:05 pmid say the best way is to wrap the cat in plastic and place it directly into the nearest trash can

author: Refrigerator
author_rank: Super Contributor
timestamp: October 03, 2014, 05:14:26 pm
content: Hmm, maybe you could throw those filthy cats into that ultrasonic cleaner as well ?