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Post subject: 1990 Twin Reverb problems.............Ahoy, Retroverbial
Posted: Sun May 22, 2011 7:01 am
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Twin Reverb (1990) question for Arjay. Have spoken to Arjay before but happy for any advice.
My Twin Reverb lost the Normal channel entirely a some months ago, Vibato was fine though,until 3 weeks ago started having a lot of noise and popping.....last week noticed reverb was almost completly gone.
At this point I pulled all tubes and connections accessable cleaned and reinstalled, changing all AT's and AX's.....no chnage still same amount of noise and still no Normal channel.
This week I changed all the 6L6GC's now I have low volume on the reverb channel only at about 5-6...........on 10 no volume........hum, now what? Still no Normal channel .
where do I go from here...help?


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Post subject: Re: 1990 Twin Reverb problems.............Ahoy, Retroverbial
Posted: Sun May 22, 2011 12:49 pm
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Judging from the symptom-development timeline, I'd opine that something may be amiss with your heater filament wiring. Are all the tubes properly lit when the amp is on?

If not, I'd check the heater wires for continuity all the way back to the 6.3VAC tap on the power tranny then clean and re-tension all of the tube sockets.

If all that checks out, start looking around where the two channels are summed together at the phase inverter, then "upstream" from there. Be sure to inspect for any wonky solder joints, burnt or cracked resistors, or a cap lead that may have snapped off.

HTH

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: 1990 Twin Reverb problems.............Ahoy, Retroverbial
Posted: Mon May 23, 2011 1:21 pm
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Thanks Arjay,
will start on this right away. I changed around some preamp tubes.....again, now I have no sound......not even popping or static, so tubes might still be involved but probaly not the main issue alone.
Back to ya' in a bit.
Thanks again,
Fred


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Post subject: Re: 1990 Twin Reverb problems.............Ahoy, Retroverbial
Posted: Wed Jun 29, 2011 9:20 am
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Ahoy Retroverbial,

Arjay, I pulled the amp head out of the enclosure, checked all solder joints with magnifying glas no breaks , nothing loose.
Also, changed around all tubes then had no volume at all, replaced all tubes with complete new matched set.......once again, I got a little bit of volume at 5-6 and no volume above or below that......also still no Normal channel at all.

I cleaned entire board, noticed very slight corrosion on the bottom line of curcit board,under channel 1 volume & tone pots..... after cleaning no break or discoloration was evendient under magnifying glass.

I did not have a decent meter to read any values at the time.
I am going to pull the amp head out of enclosure and take it to a friend with a good Fluke meter and good light . What should I look for at this point?
It is really frustrating not having this Twin working..............heavy as it is , there's still not much than can touch it.

There are no electronic techs. that I would trust with this, and sending to the states is really costly. I just got my 1969 Martin D35-S back from Florida......the luthier cahrged $300 to do a neck set but FedEx charged me $700 shipping.....painfull . Unfortunatly the guitar arrived with the top warped at the bridge and the strings are way off the fret board.......more pain.
The long and the short is that I need to fix this thinfg myself here in Grenada if possible.
Will appreciat any advice or info. Thanks again, Fred


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Post subject: Re: 1990 Twin Reverb problems.............Ahoy, Retroverbial
Posted: Wed Jun 29, 2011 9:30 am
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The amp really needs a full-service tech who's qualified down to the nuts and bolts. Not much more I can offer, I'm afraid. Sorry to hear about your D-35. A real bummer.

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: 1990 Twin Reverb problems.............Ahoy, Retroverbial
Posted: Wed Jun 29, 2011 10:39 am
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Thanks Arjay,

Not what I wanted to hear but thanks for telling me what I NEEDED to hear.
Ok, do you have a favorite full service tech. to recommend ?
Otherwise I'll send it back to Stevie B where I bought it and get them to go through it.

All the best,
Fred


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Post subject: Re: 1990 Twin Reverb problems.............Ahoy, Retroverbial
Posted: Wed Jun 29, 2011 11:59 am
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Not close enough to you that the S&H both ways wouldn't eat you alive.

Mebbe one of our south Florida members will chime in with a name.

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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