02-21-2011, 04:54 PM
I read the DIY on deep cleaning amplifiers. Seems like a lot of work. Just picked up a Sansui A-80 Integrated Amp and it came from a smokers home. The circuit boards look "greasy" wet and the unit has a bit of a smell to it. Is there a product that you can just spray on the circuit board that washes away the grime and then dissolves leaving no residue?
02-21-2011, 07:16 PM
Start with isopropyl alcohol and a toothbrush.
02-21-2011, 08:43 PM
not familiar with the A-80.
but i like to take my dirty boards out of the case and tilt it at a angle than start the side thats in the air and spray it with a can of contact cleaner. deoxit is too expensive to be wasteing like that.. so use your big cheap can of regular contact cleaner from any auto parts store..
just start spraying from the top and work your way to the bottom..
probably want to do it outside and put a cloth at the bottom where its going to run off.
and probably a cloth you dont plan on keeping either.
after all of the gunk runs off the lower end of the board
i take a air compresser and try and push out any liquid left or gunk out that may of have stayed under components..
then i let it dry well..
Unless you have a drying oven for some sort of water based detergent cleaner and a clean water rinse, I would go with absolutely pure isopropyl so that there is no residue or anything. Now it is hard to get isopropyl in spray containers, so I would get some sort of spray bottle, perhaps at a craft store or something, or recycle a clean clean household spray bottle. With the board vertical so that it will run off and rags or towels to catch runoff. Beware! Alcohol in mist or spray form would be flammable so do not get near any heat spark or flame! And you could use little hardware store acid brushes to scrub the surface while you are cleaning it. But take note that if it has pots that are the open type where you can see the carbon traces, etc. that anything you may spray on the board may also attack that carbon trace. IF they are sealed type plastic pots they may be OK. Open frame pots are a pain for cleaning due to the fact they can be damaged by solvents. And open to dust and dirt in the meantime. Maybe you could find something to put over them to keep out cleaners. Maybe. Good luck. If there are only a few of them you could remove them during the cleaning and solder them back in place afterwards. Being careful to put them in the same spots!
02-21-2011, 09:37 PM
I had a Pioneer SX-450 curb find. Filled with dirt, sawdust and splattered mud, using this and a stiff toothbrush directly on the PC board and components worked wonders.
02-21-2011, 09:56 PM
The A-80 is a weird design. The transformer is mounted to the back panel and the sides, top and bottom all come off, so when you spray the board, it will just run-off nicely. That cleaner looks pretty good, but we don't have Radio Shack in Canada anymore. I like the idea of working the cleaner with a brush to loosen the grime. I'm sure a lot of the odor will wash away as well.
02-21-2011, 10:14 PM
The last bit of rework I did involved a bit of rosin flux and that makes a terrible mess of PC boards. When cleaning it up, I started with denatured alcohol but that just spread the waxy flux around. What ended up working the best was to use a tootbrush and some mineral spirits, scrub and rinse with hot water. Next, I used the denatured alcohol with the toothbrush then a hot water rinse. Last, I used the toothbrush along with hot water and soap, then a hot water rinse.
Blowing off any excess water with an air compressor is a good idea followed by a few hours placed in front of a fan to dry any remaining fluid.
By using all three cleaners, the PC board looked like new when all was finished.
02-22-2011, 09:13 AM
I worked on old TV's years ago. In a smoking environment it was like the parts were a magnet to the smoke. The insides were nasty brown, greasy and smelly. You can't do much about it. when it's not yours.
For cleaning I would use isopropyl alcohol. A tooth brush works good. Also an acid brush (those tubular steel brushes) with most of the brush cut off. This gives you a tight scrub brush end.
If you want to use a light soap and water rinse. Use compressed air to blow out as much of the water as you can. Then put the board in the sun to dry. This will heat up everything on the board. When I did this in the Navy we had a small oven to cook the board dry. But the oven had much better low temp control than your home oven.
I never did any cleaning on transformers. If you felt so inclined I would make sure it sit's in the sun for a good day. Maybe a second. Those things are tight and full of nooks and crannies to hold water.
02-22-2011, 03:33 PM
Dropped by the electonic supply store today. Salesman recommended MG Chemicals Safety Wash II.
Did a couple of boards on the amp. Sprayed, scrubbed with a soft bristle brush, sprayed again. Cleans nicely. Allowing the unit to drip dry on its side.
Isopropyl is a pretty safe solvent. Beware of stronger solvent chemicals. THey may work fine but also might attack plastics, etc. So go easy with something not aggresive at first.
02-23-2011, 02:53 PM
I just tried CRC circuit clean from wally world today.
At 3 times the price of brake clean, it is a clear fail.