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Post subject: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Thu Nov 22, 2012 9:56 am
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HELP ME! 72 Champ bass tone pot cuts volume out past 8 and I am not sure what the problem is as soon as you turn the bass tone knob past 8 the volume goes down as you move it to ten till almost you can't hear anything. I changed tubes with another set I had from another champ and its still the same. so its not a tube problem so my guess is it could be a bad pot but I want to here what you guys on here thought before I change the pot out and I am totaly wrong!


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Thu Nov 22, 2012 4:28 pm
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It could be the pot short to ground , do you have a tester ?

With a tester you 'll be sure is bad or not ,but IMO good chance is the pot , not expensive if you can do the job


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Thu Nov 22, 2012 7:55 pm
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I do have a multimeter, but I am not sure how to check if it is a pot short and where to place the test probs. Could you explain how to do this please? I know the job is not a big deal to do since I know how to soder, but I just want to make sure it is a bad pot because I want to keep it as close to original as possible, because right now it is all original with the blue label speaker and original rca tubes. And man it sounds so good, I just need to fix the tone problem lol. If anybody has any more info I would be very greatful.


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Fri Nov 23, 2012 3:31 am
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With your tester on ohms scale 10 k aprox, connect one probe to the central pot wiper , other probe to any steel pience in the amp , or the pot itself. Turn pot slowly to read measurement.
Close to 8 to 10 , meter must show ( very ? ) low ohms reading.

There are many other test you can do , but too long to explain now if you don't need it. Look on You Tube ?

No need to disconnect the pot . Be sure amp is disconnect from wall outlet


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Fri Nov 23, 2012 11:11 am
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Ok I tried that and it does drop off from 8 all the way down to 0 ohms at 10. So just to clarify this deffently means its a bad pot and it should get higher as you go to 10 and not drop off like it does?


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Fri Nov 23, 2012 2:53 pm
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max-preston wrote:
Ok I tried that and it does drop off from 8 all the way down to 0 ohms at 10. So just to clarify this deffently means its a bad pot and it should get higher as you go to 10 and not drop off like it does?



If you do the test the way I tell you , youre reading mean the pot is short , need a new one.

I resume ; if from 1 to 7 you read very very high OHMS ( infinite ) and from 8 to 10 you read something close to 10 ohms ; pot is short


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Fri Nov 23, 2012 5:39 pm
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I fixed it lol with some compressed air and that cured the problem. I am glad I tried that before I replaced it!? Its pretty awesome what just a good cleaning can do! Thank you so much for all your help!


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Fri Nov 23, 2012 8:09 pm
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max-preston, Buy a small can of CAIG Fader Lube. Made for contact surface that require lubrication. Really works for "scratchy" and popping pots.

The 14 gram mini spray can will last you two years. Unless you are a kncuklehead---like me---and actually work on these vintage amps all the time. :lol:

Glad you found the problem!

http://ecx.images-amazon.com/images/I/41LhCthrJpL.jpg

http://store.caig.com/s.nl/sc.2/category.293/.f


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Fri Nov 23, 2012 8:55 pm
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Yeah I'll have to get some. And yeah I do work with these vintage amps to much lol but I got the amp for only 200 bucks so this buy was very hard to pass up lol and now I have 3 old champ amps lol and I did have 2 vintage twins but I sold the one to pay some bills lol and I have a 94 twin too :D


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Sat Nov 24, 2012 3:09 am
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max-preston wrote:
I fixed it lol with some compressed air and that cured the problem. I am glad I tried that before I replaced it!? Its pretty awesome what just a good cleaning can do! Thank you so much for all your help!


Good . I'm very surprise that a "dust" will make a short . I never see a short in a pot . I'm glad to learn something.

Sure a contact cleaner with lube ( or other product like BMW2002Ti write ) will help to keep this pot working for long time .


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Post subject: Re: HELP ME! 72 Champ bass tone pot cuts volume out past 8
Posted: Tue Nov 27, 2012 8:33 pm
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I know I can't believe it I just thought hay its worth a shot so I did and it worked!!! Shocked the crap out of me that it did work lol. Now I have an all original 72 champ with original rca tubes too!!!! How much would it be worth since it is completely 100% original??? Nice guitar 52 RI I got one my self awesome guitar and good looker too!!!!


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