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Post subject: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 2:20 pm
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I am hoping someone with experience could help me out with a problem my champ is having. The amp stopped working all of a sudden and I can't figure out what's wrong. The amp powers on but all I can hear is a humming noise and nothing plays through it. When I look at where the tubes are plugged in, I can see white sparks coming from the power tube. Any Ideas?


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Post subject: Re: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 2:27 pm
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Yes. It appears that your power tube has an internal short. How old is the tube? It could have just died of natural causes, or there could be a problem elsewhere in the amp that caused it to die. Do not turn the amp on again. Did the fuse blow?

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Post subject: Re: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 2:47 pm
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Bedlam9, welcome to the Forum! :D

Do you have access to a tube tester?


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Post subject: Re: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 3:01 pm
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I won't turn it on again but when I was troubleshooting, it blew a fuse. I tried other power tubes with it and got the same result. I don't own a tube tester.


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Post subject: Re: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 3:11 pm
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Look to the power supply -- possibly a runaway tranny or a power-rail resistor that went south.

When's the last time the cap can was replaced?

Arjay

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Post subject: Re: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 3:22 pm
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I don't know if anything has ever been replaced. I got the amp used and when I looked inside everything seemed old or original.


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Post subject: Re: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 3:36 pm
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Time for some major servicing as stated. You need to check the power supply components and replace the power supply filter cap can.

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Post subject: Re: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 4:13 pm
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Alright I'll let it sit until I find an amp tech. Thanks for the advice.


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Post subject: Re: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 4:22 pm
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Bedlam9 wrote:
Alright I'll let it sit until I find an amp tech. Thanks for the advice.


If you are not comfortable or don't have the tools to work on tube amps, that is your best choice.

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Post subject: Re: 1975 Fender Champ Problems
Posted: Sun Oct 13, 2013 4:33 pm
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Yeah I don't know enough when it comes to tube amp circuits.


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Post subject: Re: 1975 Fender Champ Problems
Posted: Wed Oct 16, 2013 9:16 pm
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After checking amp repair prices around town....I decided to look inside the amp myself. I managed to pinpoint the problem with the Champ and it appears to be something with the power tube socket. I attached a video to show what happens when I turn it on. Here: http://www.youtube.com/watch?v=1lsUC-zVxM0&feature=youtu.be


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Post subject: Re: 1975 Fender Champ Problems
Posted: Wed Oct 16, 2013 10:36 pm
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Looks likes you have a shorted tube. I'd have the tubes checked. And all the components, including the sockets, should be checked for defects and carbon tracings (from previous issues).


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Post subject: Re: 1975 Fender Champ Problems
Posted: Wed Oct 16, 2013 10:46 pm
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BMW2002Ti wrote:
Looks likes you have a shorted tube. I'd have the tubes checked. And all the components, including the sockets, should be checked for defects and carbon tracings (from previous issues).


+1!

Shorted tube or cracked bakelite insulator on the socket itself.

Arjay

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Post subject: Re: 1975 Fender Champ Problems
Posted: Thu Oct 17, 2013 10:19 am
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+1 looks like a shorted tube.

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Post subject: Re: 1975 Fender Champ Problems
Posted: Wed Oct 23, 2013 6:06 pm
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Taking everyone's advice into account, I was able to fix the Champ myself. Thanks for the advice.


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