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Old 25th October 2012, 12:17 PM   #1
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Default Marshall avt20 problem

Hi guys. I'm new here and am trying to get some info about my amp problem. I am new to tube amps and a friend gave me a marshall avt 20 not working. I noticed the pin to the positive speaker lug came loose so I resoldered it. Still nothing. I'm getting power and I notice the leds coming on when I push the od switch. I was thinking that the loose speaker connection could have caused me to blow a resistor since I read that you can't run these things without a load. None of the resistors look burned though. Any advise on what to check?
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Old 25th October 2012, 01:06 PM   #2
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Hey,
Note this is a solid state amp. AFAIK it only has a single 12AX7 in the overdrive circuit. Think you should seek help in the "Instruments & Amps" forum.
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Old 25th October 2012, 04:46 PM   #3
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Old 25th October 2012, 05:46 PM   #4
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Is there almost a "click" sound when power on or off the amp?
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Old 25th October 2012, 08:07 PM   #5
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Quote:
Originally Posted by revintage View Post
Hey,
Note this is a solid state amp. AFAIK it only has a single 12AX7 in the overdrive circuit. Think you should seek help in the "Instruments & Amps" forum.
Since it is a solid state amp, is it ok to have it on without the speaker load? Also, if the tube is in the overdrive circuit, does the clean channel bypass the tube? I'm not sure if the tube is good and I want to know how to test it or eliminate it as the problem.
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Old 25th October 2012, 08:11 PM   #6
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I don't hear a click sound when I turn it on or off and I checked for a voltage across the pins for the speaker and I am getting a voltage. I did manage to get some sound, but only a weird whistling noise when I touch the end of the instrument cable.
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Old 25th October 2012, 09:15 PM   #7
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I just tried using the headphone out and it worked. I also tested the speaker with a function generator. I guess there may be a problem with the speaker connection.
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Old 25th October 2012, 09:15 PM   #8
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Going to check r59.
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