Fender Capricorn / Two questions

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by gbdweller, Jul 16, 2006.

  1. gbdweller

    gbdweller Member

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    These questions pertain to a Fender Capricorn amp. Fantastic clean sound and great reverb. It's from the rare, early seventies solid state zodiac line and has three jbl's. Here are my questions:

    1. Anybody familiar with these amps?

    2. My father wanted to run a different head through the speakers and mistakenly connected the out of the head to the speaker out of the Capricorn:eek:. Now the amp does nothing but hum loudly when turned on. What could be blown? Power transformer?

    Sorry. No pics because my camera is down.
     
  2. brad347

    brad347 Member

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    i'll bet that output transformer (if any) is toast.
     
  3. John Phillips

    John Phillips Member

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    If it's a typical solid-state amp, there's no output transformer, but that sounds exactly like the output transistors are blown. That's what usually happens if someone does that, so I'd guess it's the most likely cause.

    I have no idea what type of transistors it uses or if they're still available, but it should be possible to find something which does the job.
     
  4. donnyjaguar

    donnyjaguar Member

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    John is right. If you can lay the schematic on me I'm sure we can come up with something as good or better than for replacement.

    That said, I have repaired solid state amp's with output transformers but they aren't common.
     
  5. John Phillips

    John Phillips Member

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    FWIW, I eventually repaired that old Peavey Backstage I had with some transistors which appeared on paper to be about the right spec (TIP31/32C pair) but although it works 'properly' (ie doesn't blow fuses and sounds good), it now only puts out about 5W not 20, so I must have overlooked something! ... and I did rebias it correctly. I'm assuming the new ones just don't have enough gain, I'll have to try something else.
     
  6. gbdweller

    gbdweller Member

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    Thanks guys. I don't think I'll be able to find a schematic as I can't find anything anywhere about these amps. I'll try and get a photo of the chassis and post it.
     
  7. donnyjaguar

    donnyjaguar Member

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    Are you sure there isn't one glued inside the chassis?

    Did you manage to find a schematic for this one? Working on it without one is a pain as there are so many different PA circuits used. Things that come to mind are fatigued power resistors feeding the output section - (these are sometimes installed to limit current); whipped driver transistor; sacked power transformer; imbalanced output (does the Voltage output prior to the DC blocking cap' sit about mid-rail when at idle?

    I hope this thing doesn't turn into a career breaker! :) I had to repair a stereo preamp/amp recently with no schematic. One transistor had gone noisy, but without the schema a 15 minute job took an hour.
     

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