Well this is going to be fun

[Reyhifi]

A friend tells me, I know you like to work on stereos. I have one that is not working, do you want to look at it. I said sure, is a basic receiver and he is a client as well. Has own it, for over 30 years. The plan is to get going and into his office. Who can I'd it, from the photos.
So far no sound from anywhere, but powers up. I'll post some photos, after I shovel some dirt away.

 

[hamrules]

Wow, that is amazingly dirty !

 

[newenglandj]

Realistic STA-820?

 

[Reyhifi]

Realistic STA-820?

We have a winner, kung fu is strong! after some cleaning oh what did we find.

 

[newenglandj]

HiFi Engine has the schematic, in case you don't already have it. Looks like it might be needed to determine what value that resistor should be.

I'm guessing at least one final shorted, probably the result of an open bias network. The '820 that passed through here awhile back had similar damage.

 

[Reyhifi]

HiFi Engine has the schematic, in case you don't already have it. Looks like it might be needed to determine what value that resistor should be.

I'm guessing at least one final shorted, probably the result of an open bias network. The '820 that passed through here awhile back had similar damage.

Thanks, the schematic is really hard to read. But I think I got all the values correct. Need to start checking voltages. But had to sweep in there first.,

 

[Ray66]

@Reyhifi, please share your cleaning method with us. That's quite the transformation!

 

[John James]

@Reyhifi, please share your cleaning method with us. That's quite the transformation!

I wish there was a video.

 

[dfoulk]

We have a winner, kung fu is strong! after some cleaning oh what did we find.

Good cleaning job!

 

[oldvinyldude]

I wish there was a video.

Perhaps you should look up rug cleaning "porn" videos. Or power washing versions-embarrassed to admin I watched for a couple of hours.

Yes, a great cleaning job Reyhifi!

 

[ETLS]

I'll bet next time you play "Dirty Dancing", it won't be.

 

[Reyhifi]

Perhaps you should look up rug cleaning "porn" videos. Or power washing versions-embarrassed to admin I watched for a couple of hours.

Yes, a great cleaning job Reyhifi!

Thanks a lot, still a ways to go. I was doing the faceplate today.

 

[Reyhifi]

I wish there was a video.

Haha, maybe when I do my next projects. All the ones I do, I clean to the best possible finish. i enjoy it, a bit anal and OCD.

 

[Reyhifi]

@Reyhifi, please share your cleaning method with us. That's quite the transformation!

Well the method is 'love', ok maybe just time and patience. I start with a very soft paint brush, some vacuuming. Then a stiffer paint brush, which I trimmed down. After that, cotton swabs with alcohol 90%. Finally a micro rag, lightly damp. Later I will go back in and clean some more. My average time to do, a unit like this is arounf 5-6 hours, not counting anything done to the wood case, and actual repairs.

 

[CT Jim]

I remember the thread using ‘Scrubbin Bubbles’ with small brushes and a water rinse. Worked very well last time I did one.
only takes a couple days to be dry, and you need to protect the transformer so you don’t wash the inside of it!

 

[Ray66]

I remember the thread using ‘Scrubbin Bubbles’ with small brushes and a water rinse. Worked very well last time I did one.
only takes a couple days to be dry, and you need to protect the transformer so you don’t wash the inside of it!

I used the newly resurrected AK search but only found posts on using that for vinyl. Some people use water-based methods for cleaning PCBs but I'm leery of those. Water/humidity and electronics are not a good combo.

 

[CT Jim]

I don't recall how the thread went, but it included spraying the boards with a soap solution, typically out in the driveway, after a bit using a soft paint brush to swish around the dirt, and flushing it away with a hose! Yes a water hose while the unit is tilted to allow water to flow off. I think there were also AKers who put receivers and amps in the dishwasher, but that was a bit much for me. Once rinsed, you left the unit to dry for a couple days, either in a protected sunny spot or ....also I would place a fan blowing on the unit to dry where you couldn't see.

Someone will remember this cleaning method, but my content search for any related post by me only goes back to 2020? I bet this was performed by me back in 2018 or 2017.

 

[Reyhifi]

I used the newly resurrected AK search but only found posts on using that for vinyl. Some people use water-based methods for cleaning PCBs but I'm leery of those. Water/humidity and electronics are not a good combo.

I have done at least two, with a full wash and soap with added alcohol then a alcohol rinse and baking for around two hours. Based on the Tektronix method for equipment cleaning. I might get a sad looking unit, which will require that type of cleaning.

 

[Ylli]

I've had more than one unit, totally disassembled, at the kitchen sink with a toothbrush. There are some components that you need to be careful of, but in general, most electronic components are impervious to short term contact with water. Just got to be sure everything is dry before applying power.