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112RD Volume loss

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Niall Madden (spino)
Username: spino

Registered: 05-2013
Posted on Monday, May 20, 2013 - 10:22 am:   

Hi I've got a 112RD that I have not used for 2 years and I got it out of the storage room I have in my apt the other day to check it .
After setting all control knobs on 5, I plugged in a guitar but the level was really low not what I remembered as blistering volume .
I tried both inputs ...same thing .
So I maxed all volumes and Gain to find it made little diff.
Then the volume faded to a whisper .
I removed the cable from the Guitar side and touched the Jack and no response from the Amp.
The pilot light is not shining and the
Channel Fswitch does not seem to work
This amp is in Excellent condition and I'd like to start using it in a 2 Amp setup so any suggestions would be helpful .
I'm thinking it's the Output transformer but who knows ?
Appreciate any help to get this going again .Thanks
Lars Verholt (lmv)
Username: lmv

Registered: 11-2009
Posted on Monday, May 20, 2013 - 11:36 am:   

I'm assuming this is either an RD-65 or RD-100?
Is the problem the same on both clean and distortion?

You can do a test by plugging into the insert jacks and see if you get a noise with touching the cable.

It's more likely that the signal is lost on its way to the output amp than the output amp being dead, especially if the mains fuse is not blowing.

Does the amp have 6L6 or 6CA7/EL34 tubes?

Cheers,
Lars Verholt
Niall Madden (spino)
Username: spino

Registered: 05-2013
Posted on Monday, May 20, 2013 - 06:59 pm:   

Hi Lars Thanks for the Help
112RD is 100 w
with the Vol Maxed and turning the Gain up it starts getting some Vol at 6, but very little
I already mentioned that there is no noise when I touch the cable when plugged into the Input .
Tubes are 6L6 's Matched and biased .
thanks ...Niall
Lars Verholt (lmv)
Username: lmv

Registered: 11-2009
Posted on Tuesday, May 21, 2013 - 06:24 pm:   

Hi Niall,

the insert jacks are the two right-hand side jacks. This will allow you to insert a signal after the preamp stages to help pinpoint where the signal gets lost.

Cheers,
Lars Verholt
Rob Flindall (flinly)
Username: flinly

Registered: 12-2012
Posted on Tuesday, May 21, 2013 - 08:51 pm:   

The schematic seems to indicate the pilot light is in the same circuit as the 100 microfarad/450v capacitors (C32 and C33) under the doghouse "Filter can" . If this is correct, that would be a good place to start looking. Maybe someone more knowlegdable can confirm if bad capacitors means no volume.

I have a 112RD-100 with Serial number DP08483 model 2100-RD-CAN so I am interested if this is the problem. My amp is in for repairs in the low power filter section (burned out 390 ohm resistors and 1N5353 diodes). Volume was also an issue.
Niall Madden (spino)
Username: spino

Registered: 05-2013
Posted on Wednesday, May 22, 2013 - 05:30 am:   

Sorry Lars !
So I plugged a cable into the 100mv put the Footswitch gain on 6 turned up the Vol slowly and at 6 I got a high- pitched squeal with Reverb on it .
In the 3v nothing
I 'm getting pretty loud Hum as well .
Thanks guys .
Niall Madden (spino)
Username: spino

Registered: 05-2013
Posted on Wednesday, May 22, 2013 - 05:34 am:   

Forgot to mention that the cable does react when touched
Niall Madden (spino)
Username: spino

Registered: 05-2013
Posted on Wednesday, May 22, 2013 - 05:49 am:   

Whew! After having No vol yesterday .Today I have very low dirty distortion , only when both Gain and Volume are on 10 .One without the other... No sound