How old is the Fender Super Reverb I just bought

Discussion in 'Amp Central Station' started by comax, Feb 9, 2019.

  1. comax

    comax TDPRI Member

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    Sorry again I have a question: how long caps hold the charge after the amp has been switched off?
    When the amp is in stand-by positions is it risky to touch internal components (transformers, aluminium chassis, etc.)?
    Thanks in advance if somebody can clarify this to me.
    Best regards
     
  2. viking

    viking Friend of Leo's

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    Do NOT poke around in there, you can get killed !
    Even with the amp unplugged, the big caps can hold a charge for a long time
    You have to measure to be sure, or let some one else do the work
     
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  3. clintj

    clintj Friend of Leo's

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    Caps can hold a charge for months, if not years, if in good shape. Some of the bigger vintage Fenders use resistors with the caps that usually discharge the caps after a few minutes (they're equalizing resistors, but that's a different topic), but DO NOT trust those to do that. I know at least one tech that has gotten nailed by a fully charged cap when one of those resistors failed.

    If the amp is on and in standby, the transformers and about half the power supply are still live. Pulling the chassis out to take pics is safe, as long as you don't reach in.

    Sent from my Pixel 2 using Tapatalk
     
  4. viking

    viking Friend of Leo's

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    It's really not hard to be safe, but PLEASE, you have to educate yourself a bit before diving in.
    You can read for hours about these things if you just look around a bit..
     
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  5. Wally

    Wally Telefied Ad Free Member

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    Everything...ime.... that one needs to know about vintage Fender amps is in the six articles “Dating Fender Amps”
    In this link.
    http://www.ggjaguar.com/biblio.htm
     
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  6. keithb7

    keithb7 Friend of Leo's

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    By 1968 the tube chart looks like this, it tells you nothing about date code.

    [​IMG]

    Here is an example of a doghouse in my 1964 Bandmaster. Rectangular looking cake pan, flipped upside down and screwed in place.

    [​IMG]

    Based on your questions OP, we are reluctant to send you in there investigating. As mentioned, the high voltage is dangerous to the uninformed. It does seem that you have limited amp experience. More research and understanding is needed.
     
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  7. BobbyZ

    BobbyZ Doctor of Teleocity

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    You're questions about caps already got answered. Basically I never trust that an electrolytic capacitor won't shock me.
    That mistrust comes from lots and lots of shocks!
    A voltmeter will tell you what's in them.

    To this day on the rare occasions when I'm doing a set of points in an old car or whatever, I still pull the condenser out of the box carefully and touch the lead to the body.
    That comes from a guy I worked with at a tune up shop in Dallas in 1984-85.
    He used to charge up a few condensers, (aka electrolytic capacitors) and stick um back in the boxes. ;)
     
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  8. aerhed

    aerhed Tele-Afflicted

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    Some magnetos have an impulse coupling. Like a window shade mechanism that retards the point break and uses the spring to whip it through for higher voltage. I have seen one rigged to a mechanics toolbox so it will nail a guy every time he pulls the drawer open. That was in a shop that had too much free time.
     
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  9. Wally

    Wally Telefied Ad Free Member

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    or....was it a booby trap to give a tool thief a warning????
     
  10. aerhed

    aerhed Tele-Afflicted

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    11th commandment: Thou shall not covet thy neighbor's tools.
     
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  11. comax

    comax TDPRI Member

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    Really thanks a lot for all your explanations and warnings . Actually, as all of you realized my experience is zero!
    Thank you BobbyZ, with your sentence '' Caps hold a charge so don't touch anything'' you turned on the red danger light to me!!
    I will start immediately to read about tube amps.
    I will not touch anything be sure, but just to have an idea: if, in the back side of the amp, I touch, i.e. to take pictures, the transformers, or the speakers, or other components when the amp is disconnected, would it be dangerous? Or only the capacitors inside the doghouse are dangerous to be touched?
    I will not touch anything, Just for curiosity, because yesterday to take the pics I sent, I put my head almost inside the back of the amp.
    Sorry again to burden you with all these questions, but you are very expert and very kind.
     
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  12. Wally

    Wally Telefied Ad Free Member

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    IF you wanted to pull the chassis for pictures...or just for grins, do this. Turn the amp on and plug a guitar in. Strum a chord so you know the amp is working. Then, strum a chord and turn the power switch off..leaving the standby switch in the playing mode. You will hear the caps drain as the volume falls to silence. The caps are drained. In that amp, there are draining resistors in the filter section. Leave the standby switch in the play mode. Unplug the AC from the wall. When pulling the chassis, take care not to put your fingers inside the chassis anywhere. Remove the three large tubes from the sockets....some might remove all of the tubes. I don’t remove any of them. But I have been doing this for a while, now. Removing the rectifier and power tubes allows you to set the amp down on the trannies when you want to view the circuit inside the chassis. Flip the chassis over to view the transformer codes. The dog house that covers the filter caps is on the outside of the chassis. Always take care.....and...you are responsible for your own decision as to whether or not to pull a chassis. If you have some experience working with tools and machines, you should have little trouble doing this....but that is your decision alone.
     
    Last edited: Feb 10, 2019
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  13. comax

    comax TDPRI Member

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    Really thanks Wally for your very derailed explanation.
    I will beguin reading a lot, then I will ask only experts to work on it.I will not touch anything! I will have a very safe approach!
    Anyhow I enjoied playing my SR, it has a great sound!!
     
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