Deluxe Reverb RI...again

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dustie1
Junior tube assistant
Posts: 17
(2/10/04 8:18 am)
 Deluxe Reverb RI...again
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 Sorry to start another thread on the same amp.I thought I had it worked out but.........
I was so thrilled to get rid of the motorboating i forgot all about the problem with V2.The normal channel works fine but V2 does not work at all.I am getting signal to pin 2.I have 385vdc on pin 6 of V2. About 125 more volts than on V1/pin 6 and I have 0 VDC on pin 8 of V2
I have checked all wiring,resoldered all joints in that part of the circuit,checked the ground buss and changed the cathode resistor and cap.
Any more suggestions.
I have a signal generator,scope and dummy load but don't know how to use them on a amp.I have only used them on some low voltage (15V) circuits.
Any more suggestions?Whee would this extra voltage be coming from?
 
GroundhogKen
Forum Moderator
Posts: 2251
(2/10/04 8:43 am)
 Re: Deluxe Reverb RI...again
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 Since pin 8 is 0v and there is no voltage drop across the plate resistor, it appears as though that half of that tube is not conducting. It's off.

Try swapping a different 12AX7 into that position.

When it works you should have:

Pin 6: 175v (ballpark)
pin 7: 0v
pin 8: 1.5

Make certain the heater wiring to that tube is good--one lead to pins 4 and 5, the other to pin 9.


Ken
 
dustie1
Junior tube assistant
Posts: 18
(2/10/04 9:51 am)
 Re: Deluxe Reverb RI...again
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 It was actually the tube socket.I cleaned and retensioned and now have 225VDC on pin 6 and 2.2VDC on pin 8.
The only problem left is I get nothing out of this channel.No sound at all.The normal channel works great but there is nothing out of the vibrato channel.I have checked the tone stack and grounding.Where should I be looking?
 
GroundhogKen
Forum Moderator
Posts: 2252
(2/10/04 10:14 am)
 Re: Deluxe Reverb RI...again
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 If you rock the amp, can you get the reverb tank to crash?

If it does then the return side of the reverb channel is OK. The next step is to see why the send side of the circuit isn't working.

Ken
 
dustie1
Junior tube assistant
Posts: 19
(2/10/04 10:40 am)
 Re: Deluxe Reverb RI...again
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 I hooked the tank up on the bench and get no crash.The voltages on V3 pin 1-417 ,pin 2-0 ,pin 3-7.3
On V4 pin 1-250V ,pin 2 - 0 ,pin 3 - 1.8V and pin 6 - 374V.
 
GroundhogKen
Forum Moderator
Posts: 2253
(2/10/04 10:56 am)
 Re: Deluxe Reverb RI...again
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 Since the V4 pin 6 voltage is 374, you seem to have the same non-conducting (tube off ) condition that you had on the second half of V2.

Check those grounds and socket pins on V4.

You should be able to measure 1500 ohms from V4 pin 8 to ground.

Ken
 
dustie1
Junior tube assistant
Posts: 20
(2/10/04 10:56 am)
 Re: Deluxe Reverb RI...again
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 Could it be the way I have the footswitch wired?It is not clear to me from the layout drawing.It shows the footswitch jack with a 220k resistor form the output jack which is tied to pin2 of V3 and it shows a trem footswitch wired to a .01 cap on board.The Deluxe Reverb only has the one footswitch jack and I'm a bit unsure about the wiring to it.
 
dustie1
Junior tube assistant
Posts: 21
(2/10/04 11:11 am)
 Re: Deluxe Reverb RI...again
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 I got the viabrato channel working and it sounds good.The voltage on V4 pin 6 is 250.The reverb pan will crash when I tap on it but I get no reverb when playing.
I have a wire going from pin 2 of V4 to the tip on the reverb output jack then to the tip of the footswitch jack with a 220k resistor to ground is this correct?
 
vinman753
Junior tube assistant
Posts: 89
(2/10/04 11:42 am)
 Re: Deluxe Reverb RI...again
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 yes that's right. did you try reversing the wires from the tank to the in and out in case they're mixed up?
 
GroundhogKen
Forum Moderator
Posts: 2254
(2/10/04 11:45 am)
 Re: Deluxe Reverb RI...again
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 I think the reverb return circuitry is OK.

Let's work on the dry signal send side.

What are the voltages on the 12AT7 socket V3?

Should be about:

pins 1 and 6---375v ballpark
pins 2 and 7---0V
pins 3 and 8 ---8V.

Ken
 
dustie1
Junior tube assistant
Posts: 22
(2/10/04 12:26 pm)
 Re: Deluxe Reverb RI...again
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 I've got it all working and sounding good now.Your help has been invaluable and I thank you again.
 
GroundhogKen
Forum Moderator
Posts: 2255
(2/10/04 12:39 pm)
 Re: Deluxe Reverb RI...again
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 What problem did you find?

How does it sound? Any different than the printed circuit board?


Ken
 
 
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