65 Fender Champ problems

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BrokenSkull
Posts: 17
Joined: Tue Mar 06, 2012 3:33 pm
Location: Maineville, Oh
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65 Fender Champ problems

Post by BrokenSkull »

Hey everyone, I've been working on a 65 Fender Champ, Started with a total recap. Have replaced the two 68K Resistors to pin2 of the preamp, the two 100K going to pins 6&1 of the preamp the 220K, the 1K 1 watt and the 10K 1 watt resistors, I've tested the OT and it's within spec. I've got it to the point where I can hear a very faint signal from the speaker but at a loss as too why. Voltage at pin 6 of my 12ax7 is way high, I suspect this to be the cause but I cant determine why it's so high. Any ideas?

Here's my measurements so far
12ax7
pins
1=250
2=3.6
3=1.9
4,5=6.9ac
5=0
6=372, Way high should be 205
7=0
8=0
9=0

6V6
pins
1=0
2,3=6.97ac
4=384
5=390
6=86.5
7=0
8=0

5Y3
pins
1=0
2=398
3=0
4=361ac
5=0
6=361ac
7=0
8=390
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Alexo
Posts: 477
Joined: Thu Mar 22, 2007 3:27 am
Location: The Hudson Valley

Re: 65 Fender Champ problems

Post by Alexo »

I would take a guess that the cathode resistor on pin 8 is not doing its job. Test for continuity there.. could be a bad connection or possibly the socket just needs tightening.
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BrokenSkull
Posts: 17
Joined: Tue Mar 06, 2012 3:33 pm
Location: Maineville, Oh
Contact:

Re: 65 Fender Champ problems

Post by BrokenSkull »

Thanks Alexo, You got me out of my brain funk!! I was approaching the matter backwards. It was the absence of Cathode voltage that was making the plate run hot. I replace the resistor in question, it was out of spec. But had the same problem. Then I swapped out the 12AX7 and there it was. It had a brand new 12Ax7 installed and I assumed because it was new that it was good!! Well it wasnt.

Thanks for the help!!
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BrokenSkull
Posts: 17
Joined: Tue Mar 06, 2012 3:33 pm
Location: Maineville, Oh
Contact:

Re: 65 Fender Champ problems

Post by BrokenSkull »

So now I have a new problem, originally when I tested the amp I had good volume on input 2 but low on input 1, so I replaced input 1 and the attached resistor. Now input 1 works grat, plenty of volume but input 2 has low volume. I replaced #2 with the original from #1 with no change. I dont have anymore new grounding jacks but I do have jacks that do not have the contact or non grounding. Can I use the non grounding jack or is my problem elsewhere?
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Gibsonman63
Posts: 1033
Joined: Wed May 27, 2009 1:59 pm
Location: Texas

Re: 65 Fender Champ problems

Post by Gibsonman63 »

You need a grounding jack, otherwise it will sound like you plugged a cable into the amp and unplugged if from your guitar.
BrokenSkull
Posts: 17
Joined: Tue Mar 06, 2012 3:33 pm
Location: Maineville, Oh
Contact:

Re: 65 Fender Champ problems

Post by BrokenSkull »

Ok, makes sense. Thanks
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