Tutorial: "Deep Cleaning" An Amplifier

Definitely a good read! I would add a few things.

What a great tutorial, Machineghost! Thanks for posting this.

Thank you very much.

I concur with point #6. I dont like the idea of solutions sprayed on the PCB or switches. Only turns ugly after a while.

Funny enough is that scratchy switches clears up perfectly after the procedure as described. :thmbsp:
 
This will get/become a sticky, for now I'll leave it here to build other informed opinions
and maybe add or tweak what has been said, generally as soon as something is stuck
it ceases to get anything if much added to it, so for now let's have some action on it.

----

Carry on..

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I'd like to see Echowars and others like DR*Audio (others I don't know in the SS realm)
post there thoughts and or suggestions to this thread as well..
 
This will get/become a sticky, for now I'll leave it here to build other informed opinions
and maybe add or tweak what has been said, generally as soon as something is stuck
it ceases to get anything if much added to it, so for now let's have some action on it.

----

Carry on..

------

I'd like to see Echowars and others like DR*Audio (others I don't know in the SS realm)
post there thoughts and or suggestions to this thread as well..

Fine by me. I simply posted it here with the idea that it might guide an enthusiast in their quest to restore vintage equipment. :music:
 
Great illustrated tutorial. The pictures of the dusty/dirty amp getting stripped down for a "bath" and then the assembly of the clean parts is certainly inspiring.

I have done the same process on a Revox B710 and a PR99 that came dirtier than my underpants....

I would add that a soft / worn toothbrush can be valuable in the cleaning process. Washing machine detergent is also very effective for cleaning the greasy dirt and doesn't generate too much foam.

Drying is an issue always.

I am following an old technician's advice, to rinse PCBs with tap water to get all the dirt and detergent off the PCB, blow them dry for half a minute to get excess water off, and then rinse them with 95% alcohol. 95% alcohol is much cheaper than 98% and the alcohol has the property to attract water, rinse it away and then dry faster.

I have dried the washed PCBs in the kitchen oven. Mine is rather "hitech" and the digital thermostat keeps the temperature well under control. I set it at about 50degrees Celcius (something like 115F) selecting the hot air "cooking progam". This is well below any critical temperature for components and dries the PCBs nicely and quickly.

The wire wrap repair (using solder) is a great idea. I have quite a few vintage Technics units that are filled with wire wrap and many of them seem to have developed rust.

Thanks again!
 
Some comments:
Acetone and Benzene are hazardous chemicals, extremely toxic. I would avoid using them, period. Acetone can be absorbed through the skin and get into the body that way. Not sure about benzene. Ethanol and isopropyl alcohol are good cleaners and degreasers and are much safer. However, they too are absorbed through the skin, so wear vinyl or rubber gloves.
After you wash the board, you should unscrew the transistors from the heatsink and clean off the heat conductive grease and replace it, it will be contaminated from the cleaning process.
Do not apply DeOxit to the board. It will leave an oily residue and attract dust, and, well, isn't that what you're trying to clean out in the first place?!:scratch2:
I recommend using distilled water for the rinse, or at least for a final rinse. Tap water contains minerals which you do not want left on the board.
I think this process is fine to do but overkill in most circumstances. Getting the board and all components completely dry is going to be a challenge, and there is a possibility of moving some contaminants into controls and other inaccessible areas. I would reserve this for a unit with heavy buildup of cigarette goo, kitchen grease or other funk.
 
Some comments:
Getting the board and all components completely dry is going to be a challenge, and there is a possibility of moving some contaminants into controls and other inaccessible areas. I would reserve this for a unit with heavy buildup of cigarette goo, kitchen grease or other funk.

Haven't I stressed enough that one should preferably use compressed air when drying the board and then let it dry at elevated temperatures? It is really not that difficult to dry the parts Dr Audio.
 
Haven't I stressed enough that one should preferably use compressed air when drying the board and then let it dry at elevated temperatures? It is really not that difficult to dry the parts Dr Audio.

I'll take your word for it, then.
 
Great thread! Going to give it a go on my Sansui 1000 that I'm about to restore. Many thanks, Machineghost.
 
Awesome thread/writeup and good tips from others. Not sure how I missed it until now.

To add 2 cents:

I agree with postings saying not to use Deoxit as a board spray post wash-down, as it is NOT a residue free cleaner.

I always keep at least 3 types of spray cleaner-lubes around, if not more - 1. Deoxit for most pots/switches, 2. another cheaper spray cleaner/lube that is wetter than Deoxit for rare light mechanical lubrication (WD-40 even works here although I think the MG Chem stuff I'm using is a bit better than that), and most importantly to this discussion: 3. a dry solvent-only 'contact cleaner' spray.

I'll use the solvent-only contact cleaners for any kind of washdown or rinse-out function. They are loaded with yucky VOC's but as long as you keep good ventilation, don't smoke, and don't start a huffing habit you should be OK.

Also missing from the discussion is a bit of warning about tuner section parts. You want to be VERY careful about spraying anything that leaves residue in and around a finned variable capacitor, and ferrite slug inductors are also happy to be water/solvent/junk reservoirs if you don't pay attention.

Some say "never ever ever touch or spray or clean a finned capacitor!" but I think that's hogwash... A finned capacitor full of dirt and cobwebs is going to be far more impaired than one that has been cleaned...

However I NEVER spray a lubricating substance anywhere near one and if I have to have a big washdown of a board containing one, I'll blast it with the high-VOC solvent only type rinse afterwards, with the goal of it looking as clean and dry as the day it was born.
 
Benzene was banned here as carcinogenic years ago. But I don't get why people freak out about acetone- you'll find it in most human bodies naturally. I've been splashing it all over myself for a few decades without ill effect.

Wait, maybe THAT'S what's wrong with me...! :eek:
 
Benzene was banned here as carcinogenic years ago. But I don't get why people freak out about acetone- you'll find it in most human bodies naturally. I've been splashing it all over myself for a few decades without ill effect.
Wait, maybe THAT'S what's wrong with me...! :eek:

Holy mackerel on a stick! I did not know that. Will certainly avoid it from now on.
 
Can I add a caution about "lifted" traces? You know the highway the current runs through.Take a good look at each trace and see if it is lifted anywhere.If so be very careful that any chemicals do not make the "lift" any worse.
I use de-natured alcohol and a pig bristle brush.Not hard and fast as if you were scrubbing your fingernails but long smooth strokes and not a ton of liquid.Nice and slow let the alcohol do its work.May have to clean a board five times before it shines nice and green.Slow and steady.
 
I dried parts in the oven set as low as it will go which for me is 170 degrees but then I propped the door open and used a fan to move the air around.Made it like the high desert in a wind storm!Keep an eye on it too and don't tell the wife either.
 
Thanks for writing this out, I've asked the best procedure for doing this in countless threads, and having a how-to guide in one [sticky] thread is fantastic.

danke
 
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