vibrato not working

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jsw1965
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Joined: Thu Dec 30, 2010 10:32 pm

vibrato not working

Post by jsw1965 »

Just wondering if anyone out there had any advice on this. I can't get the vibrato working on my Fender 5f11. I've done basic continuity tests but no luck. Any advice would be greatly appreciated!
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Phil_S
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Re: vibrato not working

Post by Phil_S »

marcoloco961
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Re: vibrato not working

Post by marcoloco961 »

Jon, the schematic shows three normal inputs and a trem. input. On a pic of the 5f11 I see the three inputs on the face but not the fourth trem. input. The three input jack signals wire to the grid of the first pre-tube, while the signal from the trem. input wires to the cathode of the other half of the triode. Is there a fourth input jack somewhere you need to be plugging into? Maybe follow pin 3 or pin 8 off of the first pre tube and see where they go. One should go to the trem. jack.
jsw1965
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Joined: Thu Dec 30, 2010 10:32 pm

Re: vibrato not working

Post by jsw1965 »

Hey Mark! The trem jack is a rca jack for the footswitch. By the way, I still want to hear your amp!
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selloutrr
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Re: vibrato not working

Post by selloutrr »

Continuity allows you to test the connections from component to component but have you tested the parts?

have you tried swapping the tube?
are you able to test the capacitors? Are they leaking?
have you tested all grounds?
metered Resistors and Pots?

Do you get anything when you turn the potentiometers? what do they meter?

if you have any ceramic caps replace them.

The good news it's only a dozen components and 1/2 a tube.

based on the schematic
http://www.prowessamplifiers.com/schema ... matic.html

do you have the correct voltages?
My Daughter Build Stone Henge
jsw1965
Posts: 10
Joined: Thu Dec 30, 2010 10:32 pm

Re: vibrato not working

Post by jsw1965 »

I did swap tubes and the pots seem to measure okay. The voltage is there as well. I'll test the caps this afternoon. Thanks for the advice!
tubeswell
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Re: vibrato not working

Post by tubeswell »

jsw1965 wrote:Just wondering if anyone out there had any advice on this. I can't get the vibrato working on my Fender 5f11. I've done basic continuity tests but no luck. Any advice would be greatly appreciated!
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Firestorm
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Location: Connecticut

Re: vibrato not working

Post by Firestorm »

The two most common trem oscillator problems are low gain and leaking caps. Replace the cathode bypass cap and the three caps in the phase loop and you'll fix it 9 times out of 10.
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