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How to deep clean a tube amp

Discussion in 'Fisher Forum Stickies' started by audiodon, Nov 27, 2011.

  1. busterbosco

    busterbosco New Member

    Messages:
    2
    Thank you so much!
     
  2. tapeworm

    tapeworm New Member

    Messages:
    38
    Location:
    Athens, Ga
    Wonderfull detail here! Just what I needed to read. Thank you and great job!
     
  3. 2string1

    2string1 Super Member

    Messages:
    1,122
    Don,I noticed you didn't put a foam rubber strip across the top of the glass. Is it not needed? I put one there and was wondering if it's stopping the light from coming in.
     
  4. audiodon

    audiodon AK Subscriber Subscriber

    Messages:
    9,810
    Location:
    Arlington, MA
    The strips are about stopping the light from leaking out.

    The only light leakage you would get out of the top would be light leakage from the festoons. There's already a gasket surrounding the three sides attached to the sharp edge of the chassis when you pull off the front panel.
    The #47 bulbs used in the 500-C/800-C stereo beacons wouldn't shine through the dial glass backing plate.
    If the unit is going into a cabinet, the front bezel of the cabinet will contain any light leakage from out of the top.
    That said, Iit won't do any harm to wrap the foam strips around all four sides of the dial glass.

    The other concern is light leaking out of the gap between knobs and the faceplate. That's the reason for the surround but it wouldn't happen because of light leakage out of the top. On some earlier units, Fisher furnished brown felt surrounds to go behind the knobs. I keep a small stash of those for just-in-case situations.
     
    Last edited: Aug 1, 2014
  5. 2string1

    2string1 Super Member

    Messages:
    1,122
    Thank You... I will leave it there.
     
  6. eduarsan1

    eduarsan1 Luis Eduardo Sanchez Subscriber

    Messages:
    598
    Location:
    Bogotá, Colombia
    Hi Don

    A few questions.

    I´ve planned to start the restoration project on my 400, (improving the fisher 400 thread) but is necessary the clean the chassis, the switches and pots as well (and may be paint the PT and OT´s).

    So why you don´t recommend to use the DEOXIT FADERLUBE F5 or F100 in the pots if the manufacturer says that is specifically designed to clean potentiometers (prevent damage in the carbon).

    In the other hand the Deoxit D5 is good to clean and remove rust and corrosion, and also to clean the pots???? do you recommend this cleaner??

    And finally the isopropyl alcohol can perform the same characteristics as the Deoxit D5?

    Thanks in advance!!!!!!

    Luis
     
    Last edited: Jun 6, 2013
  7. audiodon

    audiodon AK Subscriber Subscriber

    Messages:
    9,810
    Location:
    Arlington, MA
    Luis,
    1. Feel free to use faderlube if you want.

    I do not choose to use it because it contains a lubricant as well as cleaner and the lubricant will leave residue. That residue may not matter for years, but why chance it? I'm pretty sure the pots were not lubricated when new and it is now approximately 50 years later and most work.
    On the opposing side of the issue, the lubrication may be good for a stiff or dry pot(entiometer) and I do have, and I do use, faderlube when I have a stiff or dry pot.

    2. Deoxit D5 is too expensive to use as a rust and corrosion remover except in pots and other hard to reach locations that would need it.
    The advantage of any of these sprays is that you can reach areas that a swab or a rag will find find it difficult to reach or will never reach.

    I have been fortunate enough to find both lubricating and non-lubricating electronics spray cleaners that do not have the name DeOxit and therefore are considerably less expensive to purchase and come in considerably larger cans.

    3. On the use of isopropyl alcohol, feel free to try it and let us know how it goes. I do feel that alcohol often has drying properties and that can be good or bad depending on where you use it.

    Best Regards,
    Don
     
  8. AlTinkster92

    AlTinkster92 AK Subscriber Subscriber

    Messages:
    2,845
    Location:
    NC
    Thanks again Don, have read this sticky 20 times and still learn something else new.. appreciate your time on this and very helpful
     
  9. eduarsan1

    eduarsan1 Luis Eduardo Sanchez Subscriber

    Messages:
    598
    Location:
    Bogotá, Colombia
    Hi Don

    Thanks for your suggestions regarding the cleaners, I´ll let you know about the status but please sorry if I am a stubborn!! I need your advice with this:

    Using amonia and warm water (20%/80%) is possible to remove this kind of gray points in the chassis of my amp?, or do you have another procedure??. check the attached pictures.

    I don´t want to damage the lettering!!

    Once again thank you!!!

    Luis
     

    Attached Files:

    Last edited: Jun 18, 2013
  10. audiodon

    audiodon AK Subscriber Subscriber

    Messages:
    9,810
    Location:
    Arlington, MA
    The best cure for those dots on the chassis is a thorough cleaning to diminish them, followed by a coat of wax and then putting the chassis in a cabinet.
    If you seek to clean it too deeply, you'll:
    1. Expose yourself to the cadmium in the chassis plating.
    2. Leave swirlies all over the chassis.
    3. Damage the silk screen that identifies the tubes.

    The shine won't stay anyway. It will fade with time, regardless of what you do.

    The blemishes will never go away completely. Those spots are a reaction to a moist environment. The best fix is a nice cabinet to hide the chassis.
     
    Last edited: Jun 18, 2013
  11. Machineghost

    Machineghost Ghost in the machine

    Messages:
    949
    Location:
    South Africa
    Great thread!
     
  12. audiodon

    audiodon AK Subscriber Subscriber

    Messages:
    9,810
    Location:
    Arlington, MA
    I've had a PM conversation with machineghost, who has a fabulous thread about deep cleaning PCB based gear. We've agreed to cross-reference each other's threads. I'm going to edit my first post and this post to link to his thread.
    http://www.audiokarma.org/forums/sho...d.php?t=258899
    Thanks machineghost and you've done a job I can only be envious of. Great stuff.
     
    Last edited: Jan 21, 2014
  13. chadbang

    chadbang Well-Known Member

    Messages:
    742
    Location:
    Far From Home
    Great thread. The bit about cleaning the tuner glass was particularly inspired and I gave great heed to your advice and all turned out well! THANKS!
     
  14. captouch

    captouch AK Subscriber Subscriber

    Messages:
    3,779
    Location:
    Bay Area, CA
    Shining up knobs properly

    What do you guys use to shine up the brass knob brights? Mine have some pitting or oxidation. Was hoping to get them more even looking.

    You can see an example here:
    [​IMG]
     
  15. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

    Messages:
    19,111
    Location:
    Glen Burnie Md.
    Brasso or Noxon7 on a Terry Cloth. Lay on a flat surface and drop the face of the knob in it. Let sit for about 10 minutes or so, then grab hold and start making figure 8's in the terry cloth. Use a fair amount of pressure. Add more cleaner to keep from drying out as needed. Check surface every couple minutes. When you get the desired effect, rinse in hot water and DAWN. DRY Thoroughly and use a carnauba wax.
     
  16. captouch

    captouch AK Subscriber Subscriber

    Messages:
    3,779
    Location:
    Bay Area, CA
    Thanks Larry, sounds good. Appreciate it.
     
  17. Glass Prison

    Glass Prison AK Subscriber Subscriber

    Messages:
    867
    Location:
    Saskatoon,SK,Canada
    This is awesome. I got my work cut out for me on a 500 I just got. I didn't know that this sticky even existed. :thmbsp:
     
  18. MikeRam

    MikeRam Active Member

    Messages:
    155
    Location:
    Portland Oregon
    Deoxit substitute

    Don,

    Would you mind sharing with us the cheaper alternatives to Deoxit that you use? I'm always looking for a better deal :D

    Thanks,

    Mike
     
  19. Fisherdude

    Fisherdude Regular Dude - Super Mod Super Mod Subscriber

    Messages:
    27,606
    Location:
    Out West.
  20. audiodon

    audiodon AK Subscriber Subscriber

    Messages:
    9,810
    Location:
    Arlington, MA
    I buy some stuff at an independent local electronics store.
    It's a non-lubricating spray . . . which is key when you don't want to leave residue.

    It's on this page - look for 409B:
    http://www.youdoitelectronics.com/MG/id215.htm

    MG Chemicals Electrosolve Contact Cleaner
    409B
    Contains Isohexanes. A general purpose contact cleaner that quickly penetrates and dissolves most soil types.

    Non-conductive
    Extremely flammable
    Safe on plastics
    Fast dry
    Medium toxicity
    Low cost
    Zero residue
    Available Sizes
    409B-140G 140g (5 oz) Aerosol
    409B-340G 340g (12 oz) Aerosol
     

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