102 problem

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galtjunk
Posts: 247
Joined: Mon Jan 30, 2006 1:23 pm
Location: NM

102 problem

Post by galtjunk »

I built a 102 with a precision power supply.
Everything was working fine.
I took the inputs apart in order to add a switched pot to the fet.
The clean channel works with and without the fet switched in.
I pulled the od relay out of the socket and manually jumpered it to test it.
The od relay is working properly.
When I switch to the od channel it goes dead quiet.
I swapped the tubes in v1 and v2 and nothing changes.
Clean still works, Od doesn't work.
I measured the voltages in v2 and pins 6 and 8 were what they should be.
I found that pin 1 was high at 340 and there is no voltage at v2-3.
There is continuity between pin 3 and the cathode cap and resistor.
Is there anything other than a bad socket that would cause this.
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erwin_ve
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Re: 102 problem

Post by erwin_ve »

Is there continuity between ground and cathode for v1 pin 3?
Voltage for pin1:340v is indicating no current flowing.
Normally you would see a high voltage at pin3 when there's no ground.
Socket would be my first suspect.

Erwin
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galtjunk
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Joined: Mon Jan 30, 2006 1:23 pm
Location: NM

Re: 102 problem

Post by galtjunk »

Is there continuity between ground and cathode for v1 pin 3?
Voltage for pin1:340v is indicating no current flowing.
Normally you would see a high voltage at pin3 when there's no ground.
Socket would be my first suspect.

I have continuity from pin 3 to the resistor/capacitor.
I have continuity from the resistor to the cap ground.
I'm guessing that it is the socket.
talbany
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Re: 102 problem

Post by talbany »

Take the tube and unplug and pop it back in several times (4-5) quickly, sometimes this will clean out a dirty socket and will come back on..If it works again you at least you know it's a dirty socket, then
Repeat procedure with some contact cleaner..
An old tube jockey taught me this trick 8)

Redneck Amp Repair Service!
" The psychics on my bench is the same as Dumble'"
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galtjunk
Posts: 247
Joined: Mon Jan 30, 2006 1:23 pm
Location: NM

Re: 102 problem

Post by galtjunk »

Great suggestion.
It cured my problem.
Thank you.
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