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Good evening.....I have this amp here and this is strange.......does Fender ever release any modifications on their equipment....The reason I ask is that I have this amp here and it has a reverb problem.....When I removed the chassis and took a look inside I saw a capacitor labeled C95 which was lifted from the board on one end...the schematic shows a value of 22uf/25V and is a bypass cap on the cathode of a tube....namely V4A...this cap tested good for both the value and the ESR....then I saw a resistor labeled R163 which is a 220K which checked good.......there is a 100K resistor tack soldered in parallel with it...and the leads on this resistor are too long......now for the problem at hand.....the reverb control when turned up past 5 will start to get noisy and as you increase the control the volume will decrease..........and when fully increased you can hear a very faint very high pitched squeal almost beyond the reach of my hearing...and my hearing isn't perfect by any means....I re-connected the cap and I temporarily lifted that 100K resistor but basically no change....any ideas?? Tubes check good and I swapped out V4 for a quick test....
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Not too sure about the Super Sonic (good name for the noise you are hearing, huh?).
I do know there are Factory tacked on bits on the Hot Rod Deville. -
Sounds like it is breaking into oscillation at the point where raising the control starts to reduce the volume.
Check the reverb cables and grounding.Originally posted by Enzo
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Fender does send out service updates for different amps, I'm not sure if there are any for the Super Sonic.
In any case, Fender would never tell anyone to lift a cap by one end and leave it hanging. Sounds like somebody else was trying to fix the oscillation problem before you, by reducing the gain of that stage.Comment
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Actually...I contacted Fender and they sent me in some service updates for this amp...but nothing there for the problem at hand.....I am going to take a shot of the board so they can see what I am talking about.....I contacted the store and they had taken it in on a trade.....so probably somebody else was inside this like you suggested.....and what they had done didn't work....I am going to restore it to the original and then work from there......Originally posted by 52 Bill View Post
Thanks for the replies g1 and 52 Bill.....much appreciated.....now to sit back for a bit and watch the comedy show on CNN.......to be quite honest, the U.S. is not the only country that doesn't have much of a choice when it comes to electing leaders.....we have the same problem here in Canada on the federal level and also at the provincial level.....the idiot we have here for premier, Dwight Ball, needs to have a serious attitude adjustment.....he has to be one of the biggest crooks in our local political history.......Comment
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What's Danny Williams up to these days? Ready for a comeback?
Originally posted by Enzo
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Danny boy is actually building his own sub-division with it's own shopping center and naming it Galway Place after his mother or grandmother......access to it will be off the Trans-Canada highway and up at the end of Mt.Pearl about a 10 minute walk from where I live.....supposed to have a golf course there as well.....as far as getting back into politics, I doubt it....when he was premier, he didn't take a salary....he didn't need it...before he went into politics, he sold his cable company to Rogers for over 100 million...plus he was one of the most sought after lawyers around.. he donated his salary to Memorial University.....he was a multi millionaire before he ventured into the political arena.....Originally posted by g1 View PostWhat's Danny Williams up to these days? Ready for a comeback?Comment
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"I contacted Fender and they sent me in some service updates for this amp..."
Can you post them?Comment
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I had to sign a disclosure statement when I started doing stuff for the store....Originally posted by Jazz P Bass View PostComment
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I figured it out after.....I had to disconnect the added resistor, re-install the elect. cap, re-install the tank in the opposite direction and had to replace the 12AX7A recovery tube with a 12AU7A ans there was too much gain and causing excessive feedback when the reverb control was turned up at a high level.......Just thought I would let you know...
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It was a head scratcher for me for a bit.......I read somewhere awhile back that somebody had a similar issue with a reverb problem in a combo and had solved it by removing the tank and rotating it 180 degrees and re-installing it...so I did that....and when the reverb only caused feedback at high levels, I remembered that the 12AU7 is the same as the 12AX7 but with lower gain so I tried that....and it worked......so I learned something new......and a thank you to everybody who offered suggestions.....
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