Where there's smoke.....YIKES!

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by djem, Sep 15, 2006.

  1. djem

    djem Member

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    Luckily, there was no fire.

    During last night's jam, I was really digging the tone I was getting from my Traynor YBA-1 Bassmaster (early model with tube rectifier). Just as I was in the middle of a solo, I noticed the sound level drop accompanied by a funky smell. I turned around and saw smoke pouring out of the amps inputs.

    Turned the amp off real quick and unplugged it. Upon inspection, the inside of the amp received a Peter North capacitor eruption and was covered with this black oily goo :( .

    1) How bad is this? Is my amp pooched?
    2) What's the best way to remove the goo? (after discharging caps of course).
    3) The biggest thing that worries me is that now I'm paranoid using my older amps for jams in fear of the same thing happening again. Is there anything I can do to prevent this or diagnose early on? :(

    All comments welcome.

    Thanks,

    dj
     
  2. brad347

    brad347 Member

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    Well, now you have to find a good tech to "put the magic smoke back in."

    In answer to number three, you can prevent this by making sure you have quality FRESH caps in, that you KNOW the age of, that are less than 15 years old, installed with correct polarity.
     
  3. djem

    djem Member

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    I had to quit that when I started dating the lady who became my wife.

    Thanks for the tip on #3 on new caps.

    dj
     
  4. donnyjaguar

    donnyjaguar Member

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    I'm a big fan of leaving the vintage caps in an amp. I can probably guess what happened here though. The electrolytic had some internal resistance that heated it up. Because the amplifier was already hot from the tubes the ambient air around the electrolytic got too hot and caused it to vent its electrolyte. This is very true of Traynors as the capacitors are inside the chassis (and also why other amplifiers use the chassis mounted can caps or a separate enclosure altogether). The good news is its an easy fix and you should be able to find new cap's with much higher temperature ratings.

    DJ
     
  5. brad347

    brad347 Member

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    i'm a big fan of leaving original everything in an amp except power supply electrolytics. To me, that's like leaving the original brakes on a car 'just because.'
     
  6. SteveStrat

    SteveStrat Member

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    Nice analogy!!! I just about "erupted" coffee all over my monitor atfter reading that. hahahhahaha

    Steve
     
  7. doctorx

    doctorx Member

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    You should take the amp to a qualified tech for the repair, and a cap job. Have all the electrolytics replaced and the amp rebiased, and your problems will be over.
     
  8. Blue Strat

    Blue Strat Member

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    .... and if this had been done as a preventative measure, as it should be, we wouldn't be having this conversation.
     
  9. TheAmpNerd

    TheAmpNerd Member

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    +1 What Mike said.

    The key is ALL electrolytics, including:
    • Power Supply
    • Bypass Caps
    • Bias Supply
    Have the other caps checked for leaks.
    Resistors measure for tolerance.

    Pots, sockets, jacks cleaned and tightened.
    Tubes tested and rebiased.

    This is the minimum that should be done to older amps.

    But that is me.

    Some folks also like the sound of
    water soaked 50 year old CC resistors too.


     
  10. doctorx

    doctorx Member

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    Not all YBA-1A's have internal filter caps. I have two of them and they both have can caps.
     

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