Cat piss

[Randall]

OMG. A Fender Rumble 500 combo amp comes in. Guy loads it into my shop, and THEN tells me one of his 8 cats "used it as a urinal". But, it's OK because he sprayed it with isopropyl. I bit my tongue, because first of all, I don't like cats, and they don't like me, and I could smell this foul odor from 6 feet away. But, work has been slow lately, so I don't turn him away.

I turn it on, and it screams like a stuck pig, even with every control turned down. I get into it, decide the issue is with the preamp/control board, so I pull it. There is a nasty, crusty substance covering a small section of the board, including a surface mounted IC. I start to scrape away at it, but quickly get totally disgusted. I pull the board out, and head to the sink. Eff it, this board is getting wet, because I am not getting this funk on me. I scrub it with an old toothbrush, and remove the nasty crud as best I can. I set it aside to dry for a couple of hours.

When I put it back in, it made some of the same noises, but a lot less, and a lot less loud. It kept it switched on, and after about 5 minutes, the noises went away. It has been on now for three hours, and is working fine. I wonder why about the last part of this. Maybe it wasn't totally dry, and thus still conductive somewhere? I don't really know, but if it is still working well tomorrow, this POS is headed to the exit door.

God, I hate cats.

[Jon Snell]

The problem may rear its ugly and smelly head later down the road. I hope you agreed no warranty on your repair.
As soon as moisture from the air condenses on the uric acid, corrosion will set in under the copper traces unless you are very lucky and have washed it all away.

As a Regional Service Centre for many manufacturers, before I retired, I would see "Under Warranty" items, returned by customers to the dealer who sold them, to be sent to my workshop for a warranty repair.
There must have been quite a few that were contaminated with you know what.

The best one I had sent in was a Panasonic Camcorder that no longer worked at all.
On removal of the case, all of the copper track was green with corrosion.
That was obviously not under any warranty but there was no nasty aroma.

After almost half an hour on the phone to the customer, it transpired that the owner popped home but didn't have time to take the camera into the house for some reason, he placed the camera in the washing machine and covered it with laundry for safe keeping.
The lady of the house popped in, whist he was out not checking the washing machine, put it on a cotton wash.
The result was catastrophe.
Perfectly clean on the outside and nothing worked on the inside. Even the view finder has a cloudy coating on the screen with no picture.
I suggested he should have used Ariel Biological Washing Liquid... (maybe he would get a better picture).
He did laugh in the end.

I prefer animals to people, they don't tell lies.

[Enzo]

Nothing at all wrong with washing the board with water. But as dry as you may think it LOOKS, water remains wicked under the ICs and other parts. It can take longer the dry than you think. I always set a board on edge to dry, not lying flat. That way any water wants to run out from under things.

In college I worked in a microbiology lab, yes, washing test tubes. We washed them in special dishwashers with special cleaners Then we rinsed them with distilled water. Then rinse in alcohol, and a final rinse in ether. Alcohol and water mix, but alcohol evaporates much faster, taking water with it. And ether mixes as well evaporating even faster. Left things bone dry.

By the way, when old NiCad memory batteries left too long spooge on your board, I found Lime Away worked pretty well to remove it.

[gui_tarzan]

Dry it off in a microwave, that'll take care of those squeals!!!

Of course I'm kidding. I knew alcohol would wash away any water left over but I didn't know about ether.

[Randall]

I did pour 91% alcohol over the board after washing it. But maybe I didn't let it dry long enough. It's the next morning now, and working fine, so out the door it goes.

[xtian]

Late to the party, but: You can bake PCBs in the oven. No kidding. 150-200 degrees F will evaporate any water without harming the board (alcohol first, to wash out the water, as mentioned above). And I even baked an intermittent Fender Super Champ XD reverb PCB back to health at 350 degrees for 30 minutes.

[The Dude]

I had a guy bring a camcorder in for repair a few years back. He said it was dropped in a lake while he was fishing. When I opened it up, it was completely corroded and many leads completely gone and traces eaten away. I was amazed at how quickly damage had spread.................................................. ........ until he told me that it was dropped in the lake the previous summer (1 year prior).

[tedmich]

Urine is every bodies way of removing ions, thus the salty taste (I'm told) and as such nonpolar solvents (like Enzo's ether rinse) won't remove the dried residue at all. But Enzo's march from polar solvent (water is king) to alcohol (has one of waters -OH groups) to ether was a good way to remove water soluble compounds and leave little/no residue. Goo Gone/ Limonene can help here too, remove non polar stuff (grease etc) then water removes the cleaner quite well, so much that its replaced freon to clean silicon wafers.

I'd rinse with distilled water, totally submerged and changed a couple times (its cheap) then maybe a spray of the goo gone followed by another rinse and a long thorough drying (we'd use a vacuum in the lab and/or silica gel or molecular sieves to pull the water out.) Acetone also does a great job displacing water and then evaporating cleanly but it can also melt components, masks etc and is a bit toxic.

[Chuck H]

Urine is every bodies way of removing ions, thus the salty taste (I'm told) and as such nonpolar solvents (like Enzo's ether rinse) won't remove the dried residue at all. But Enzo's march from polar solvent (water is king) to alcohol (has one of waters -OH groups) to ether was a good way to remove water soluble compounds and leave little/no residue. Goo Gone/ Limonene can help here too, remove non polar stuff (grease etc) then water removes the cleaner quite well, so much that its replaced freon to clean silicon wafers.

I'd rinse with distilled water, totally submerged and changed a couple times (its cheap) then maybe a spray of the goo gone followed by another rinse and a long thorough drying (we'd use a vacuum in the lab and/or silica gel or molecular sieves to pull the water out.) Acetone also does a great job displacing water and then evaporating cleanly but it can also melt components, masks etc and is a bit toxic.

I'm pretty sure you can't rinse away Goo Gone with plain water.?. It's "oily" and therefor not water soluble? Maybe I don't know what I'm talking about here since my experience with Goo Gone is limited.

Urine is every bodies way of removing ions, thus the salty taste (I'm told)

Ok... Fess up already

[g1]

Ok... Fess up already

Well, he couldn't have heard it from Ghandi: https://www.newsweek.com/explain-you...own-pee-375339

[Chuck H]

Must have heard it from Bear Grylls then.

[tedmich]

I'm pretty sure you can't rinse away Goo Gone with plain water.?. It's "oily" and therefor not water soluble? Maybe I don't know what I'm talking about here since my experience with Goo Gone is limited.

You are right limonene is not water soluble so rinse with a little bit (drops!) of Dawn liquid in DI and then end with DI water.