How to deep clean a tube amp

While looking at the 500B the other night, I got to thinking about another way to clean the knobs. I took the "D" shaped shank from an old potentiometer and cut it, then put it in my variable speed reversible drill and set it to low speed (100 rpm or so). Put a knob on the shank and held a towel with a dab of Brasso against the knob cap and ran the drill in both forward and reverse. It allowed the Brasso to get into the machined grooves of the brass cap without leaving swirl marks. Wash, rinse, dry and wax as before.

For the smaller size, dual knobs (Bass and Treble controls), I found a piece of wood dowel and cut it so it would fit the knob. A larger dowel would also work if you don't have a scrap potentiometer.

This procedure also works on the larger knobs with the brass rings such as on the X202! On those, it will shine up the brown plastic fronts but keep the speed LOW or you could start to melt the plastic or damage the ^ markings.
 
That's CHEATING! Rubbing brass with Brasso to a faultless shine is a character building exercise. And we've got too many "Characters" here. SO CHEAT AWAY!!!!
 
I polish all my stuff on a buffing wheel on a haf horse motor using buffing compound. cant beat it for mirrior finish.
used it on all my old cars stainless trim during restoration.
 
I did all the stainless on my cars, too. Makes a LOT of dust, especially the white rouge. Probably took 3 years of life out of my lungs... And you can't do just one part, you gotta do them all, like rechroming one piece throws the whole car off...

Brasso is CHEATING? Try SILVO! I had a tough time finding Brasso a few years ago. I still have some in the old metal can.
 
Brasso was almost Army issue for us Army guys back in the 60's! Show up in formation with a dull brass belt buckle. KP or give me 50 push ups! :D
 
Navy Found back in the late 50's that the amount of Brasso being used on Torpedo tubes on Sub's was removing enough of the tube thickness to actually cause the NAVY to banish it's use on Torpedo tubes and piping exposed to full sea pressure on Submarines.

Run she might. SHINE SHE MUST!
 
Don asked me to put my thought's down on using "Scrubbing Bubbles" Bathroom cleaner on chassis. Don't use the scented versions. The plain version is the best.

This is for chassis' in excellent shape with a need for light cleaning. Chassis' with rusting or other heavy corrosion will need more aggressive methods.

1.) It's good on lightly dirty (Mainly dusty) chassis. Heavy dirt will have to come off with something more agressive. But for light dirt it works well. SHAKE CAN VIGOROUSLY BEFORE and DURING USE.
2.) Use a paint brush to stir it around and get the dirt mixed into it. A 1" or 1/2" art brush is sufficiently stiff.
3.) Wipe off with Scott shop towels.
4.) spray chassis BEFORE IT DRIES with 91% Isopropyl Alcohol and wipe down. This gets the residue/stains off.

5.) Don't get either the Scrubbing bubbles OR the Isopropyl on or in the TUNING Capacitor. Use CRC QD Contact cleaner or other NON RESIDUE Electrical cleaner.

Set unit up on side, start at top and work down with Isopropyl which will displace the water in the scrubbing bubbles. Get in the crooks and nannies...UHHHH Nooks and crannies. Set up a fan to help evaporate liquids, and set in the sun. I do this for 2 days after cleaning. Baking @ 175 upside down for 4-6 hours is optional and depends on how your better 1/2 likes her oven being used for a drying rack.

DO USE A VARIAC AND DBT on 1st power up. Check all voltages. If everything is ok, you're good to go.
 
Here's a link to the AEA Audio tube amp cleanup thread of April 2015. There are some good ideas here.
Remember, there's no single way to do this, but the common goal of getting this tube amp clean, which through the miracle of convection draws and filters all kind of household dust, smoke (from the old days mostly), cooking smells, and pet hair and who knows what else, is something we all share.
There's something to be learned from everyone's experience.
http://www.audiokarma.org/forums/showthread.php?t=655366
 
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Painting in the indented indicator markings on knob brights
I'm working on a Fisher 500C, all the brights are intact and responded well to Mothers polish. However, the small black indicator indents have lost most of their paint. Any ideas on how to color them in for a really clean appearance?
 
I think a good tool for removing knobs would be the plastic pry tools used for removing car interior plastic panels.
 
any special tricks for removal of the treble/bass full double knobs?
Or they slide off as the others?
Just got a 400 CX-2 and trying to make it bit more civilized...
Thanks!
 
ok i was able to take them off.
This is the third I think Fisher I am cleaning but somehow I cannot veer have the faceplate really nice and clean. Wondering if simple green or similar can be used?
I my experience (and it was proven again with the 400 CX-2) Mr Muscle leaves a residue, although cleans effectively. Followed by light alcohol and then a recommended warm bath with mild soap resulted in OK results...
 
Knobs slip off. If you have the room between the knob(s) and the faceplate, a couple of teaspoons (don't use SWMBO's good stuff) slipped under the edge on opposite sides and push down on the handles evenly will pop off the outer one like a Redstone Rocket (just keep an eye on the trajectory, it'll be sub-orbital). The back one will slide right off after the front one pops off.
 
Don is there a way to address a chassis that is heavily corroded? Here is a Fisher 400 that is heavily corroded on top? Many thanks!

348AFEC6-4874-4577-93F7-D3B8E2D3BD6E.jpeg
 
Theron; Don passed about 3 yrs ago. Follow suggestions in post #69 and in Madwing's pdf in post 72 this thread. A rinse with a garden hose 1st. Won't hurt it because you're gonna dry it out in front of a fan for a couple days after letting it "sunburn". As for the rust, get some "NAVAL JELLY" or rust converter.

1.) Remove the tubes, marking them for position per the manual. (ie: V1, V2, V3 etc). Put them in a safe place.
2.) Remove the bottom panel. (it's gonna get wet, so makes it easier to drain and dry.

With the UNIT on IT's SIDE (power tranny DOWN)

Clean the mouse piss off with the scrubbing bubbles and a 1 to 1-1/2" chip brush. Don't be shy about it. Flush with water from the hose. Try to keep as much water out of the IF /RF tuning coil towers as possible (tape off the holes and spot clean as needed). If you have compressor, hook up the blow gun and give EVERYTHING a decent blast, TOP TO BOTTOM.

Now you can get the Rust converter out and follow directions on the jar. Try to keep it out of the tuning capacitor (you'll clean this later by pulling the cover off). Rinse off with a heavy spray from the hose, (again top to bottom.) Blow it down with air. Then prop up one side so the top of the unit is about 45* and facing the sun for the afternoon. A small fan blowing toward the underside will help with any condensation underneath. When the sun drops, put it on a bench on it's side, and let the fan hit it overnight. Get the wife's ok for this next part (unless you have a spare oven in the garage she don't care about). Place the unit in the oven (UPSIDE DOWN!), set temp for the absolute LOWEST SETTING (170*F is usual), and bake it for about 4-6 hours. As it's been literally out in the open (in Md. summers) for 30 years, you want to literally bake out any residual moisture in the transformers. Moisture/steam will escape from the wiring holes (that are now on top). Let it cool down with some fan support.

Remove the small cover over the Tuning cap. You'll need a 1/4" nut driver for this as you have to remove the cover underneath, and 2 nuts in the RF section IIRC. Get a can of CRC QD Electronics CONTACT CLEANER (Home Depot in Electrical Dept). UN-MESH the leaves on the cap (turn the tuning dial knob), and spray the contact cleaner on the leaves heavily. Let dry, while you clean the cover.

The pitting of the chassis is inevitable. Tape off the tube sockets, transformers. Automotive Gray primer then Rustoleum or Krylon Silver. Don't use the chrome stuff. Hi-Heat engine paint will reject the heat from the tubes better, but the normal rattle can paint does well. You want a buff (semi flat) finish. Use a Dymo label maker (small font) to make labels for all the tubes. Trim down to just the lettering and place next to each tube for ID.

You can take off the transformers (take plenty of pictures of the wiring and where it goes for each, plus make a diagram on paper for back up.) and paint them black. Semi gloss or gloss (depending on taste). After color coat and labeling, a light clear coat will seal all of it. Aftr painting let it dry and "DE-GAS"/Bake out in the sun for a couple days.

While you have them out, test all your tubes. Replace any that show shorts or weak. 12ax7's are twin triode so there are 2 tubes in one envelope. They should be close for emissions and or gm (if you have a gm tester.). If a basic emissions tester make sure they test in the good range. Clean the pins with DeOxit and a small handheld brass brush. Tube sockets use DeOxit and an InterDental Brush (braces brush).

1st power up. Make yourself a DBT (Dim Bulb tester (Google it)). Use a 100W bulb. Put all tubes in, connect a cheap, disposable pair of speakers (8ohm) and power it up. If no problems the bulb will light up brightly and within a second or 2 dim down. If not, TURN IT OFF! Now the troubleshooting begins.

Get it cleaned up, and report progress (with pics).

Larry
 
Theron; Don passed about 3 yrs ago. Follow suggestions in post #69 and in Madwing's pdf in post 72 this thread. A rinse with a garden hose 1st. Won't hurt it because you're gonna dry it out in front of a fan for a couple days after letting it "sunburn". As for the rust, get some "NAVAL JELLY" or rust converter.

1.) Remove the tubes, marking them for position per the manual. (ie: V1, V2, V3 etc). Put them in a safe place.
2.) Remove the bottom panel. (it's gonna get wet, so makes it easier to drain and dry.

With the UNIT on IT's SIDE (power tranny DOWN)

Clean the mouse piss off with the scrubbing bubbles and a 1 to 1-1/2" chip brush. Don't be shy about it. Flush with water from the hose. Try to keep as much water out of the IF /RF tuning coil towers as possible (tape off the holes and spot clean as needed). If you have compressor, hook up the blow gun and give EVERYTHING a decent blast, TOP TO BOTTOM.

Now you can get the Rust converter out and follow directions on the jar. Try to keep it out of the tuning capacitor (you'll clean this later by pulling the cover off). Rinse off with a heavy spray from the hose, (again top to bottom.) Blow it down with air. Then prop up one side so the top of the unit is about 45* and facing the sun for the afternoon. A small fan blowing toward the underside will help with any condensation underneath. When the sun drops, put it on a bench on it's side, and let the fan hit it overnight. Get the wife's ok for this next part (unless you have a spare oven in the garage she don't care about). Place the unit in the oven (UPSIDE DOWN!), set temp for the absolute LOWEST SETTING (170*F is usual), and bake it for about 4-6 hours. As it's been literally out in the open (in Md. summers) for 30 years, you want to literally bake out any residual moisture in the transformers. Moisture/steam will escape from the wiring holes (that are now on top). Let it cool down with some fan support.

Remove the small cover over the Tuning cap. You'll need a 1/4" nut driver for this as you have to remove the cover underneath, and 2 nuts in the RF section IIRC. Get a can of CRC QD Electronics CONTACT CLEANER (Home Depot in Electrical Dept). UN-MESH the leaves on the cap (turn the tuning dial knob), and spray the contact cleaner on the leaves heavily. Let dry, while you clean the cover.

The pitting of the chassis is inevitable. Tape off the tube sockets, transformers. Automotive Gray primer then Rustoleum or Krylon Silver. Don't use the chrome stuff. Hi-Heat engine paint will reject the heat from the tubes better, but the normal rattle can paint does well. You want a buff (semi flat) finish. Use a Dymo label maker (small font) to make labels for all the tubes. Trim down to just the lettering and place next to each tube for ID.

You can take off the transformers (take plenty of pictures of the wiring and where it goes for each, plus make a diagram on paper for back up.) and paint them black. Semi gloss or gloss (depending on taste). After color coat and labeling, a light clear coat will seal all of it. Aftr painting let it dry and "DE-GAS"/Bake out in the sun for a couple days.

While you have them out, test all your tubes. Replace any that show shorts or weak. 12ax7's are twin triode so there are 2 tubes in one envelope. They should be close for emissions and or gm (if you have a gm tester.). If a basic emissions tester make sure they test in the good range. Clean the pins with DeOxit and a small handheld brass brush. Tube sockets use DeOxit and an InterDental Brush (braces brush).

1st power up. Make yourself a DBT (Dim Bulb tester (Google it)). Use a 100W bulb. Put all tubes in, connect a cheap, disposable pair of speakers (8ohm) and power it up. If no problems the bulb will light up brightly and within a second or 2 dim down. If not, TURN IT OFF! Now the troubleshooting begins.

Get it cleaned up, and report progress (with pics).

Larry
Thank you very much Larry! My Condolences about Don. This is extremely helpful and will report back with pics!
 
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