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Post subject: What’s up with the clean channel on my Fender Champion 30?
Posted: Mon Jun 03, 2019 7:19 am
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Hi folks!

Picked up a Fender Champion 30 over the weekend for a Jackson and it works, but... not really how it’s supposed to. The amp has two separate controls: a single volume pot for clean, and a separate drive and volume pot for overdrive. Currently, however, the volume pot for clean doesn’t work at all, but the drive and volume pots that should only affect the overdrive channel also control the clean channel. So basically, both channels sound like overdrive.

These mim’s are apparently kinda notorious for bad solder joints, and sure enough, there were about a half dozen on the pcb, mostly pot leads. I ended up retouching every point with fresh solder, and while that fixed some problems (less hum!), it didn't fix the channel switching. The LED turns off, but I have to assume whatever relay switches the drive has a short.

Unfortunately, I don’t have a ton of experience with schematics, but I have found at least one resistor (R69, one of the large white rectangular ones) that is reading 0 when it should be reading .3 on my multimeter, so at the very least that one has to go. Has anyone experience this or something similar? Any tips to help my search?


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Post subject: Re: What’s up with the clean channel on my Fender Champion 3
Posted: Tue Jun 04, 2019 1:46 am
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Joined: Fri Feb 05, 2010 4:31 am
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R69 ; 0.33 or 0 ohms is not the issue you are looking for.

1-You must disconnect one side to read.
2- Is your meter is accurate ?


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Post subject: Re: What’s up with the clean channel on my Fender Champion 3
Posted: Wed Jun 05, 2019 9:31 am
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Joined: Thu Aug 07, 2014 3:25 pm
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If the red Drive LED is working, the only parts left in the swithcing circuit are Q1 and Q2. These are Jfet switches that often cause switching problems. They are cheap and easily available.
While you are ordering, get a TLE2072CP for the U1 position. Its an upgrade for the stock TL072 and sounds much better.


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