04-19-2009, 08:56 PM
Well here's what I've got now. Induce the 455khz signal into the grids of both XXL tubes and I get nothing from the speaker.
Induce the same signal into the grid of the 1st IF 7B7 and I get nothing.
Induce the same signal into the plate of the 1st IF 7B7 and I hear my expected noise from the speaker. Same with the grid and the plate of the 2nd IF 7B7. Yes! I do get my noise at the grid of the 2nd IF 7B7.
So is my signal not getting through the 1st IF 7B7? This tube has been swapped out with two other known good tubes. Sockets on "ALL" loctals have been cleaned thoroughly and I even checked continuity between pin hole and terminals of all sockets where the components and wires solder to. All is good. And of course all the tube pins have been cleaned too.
Why do I get nothing from the grids of the XXL tubes?
Once again I have to say that I have rung out all circuitry and checked all connections of components and checked that all components are good in their values etc. All IF's have been opened up and checked for proper resistance.
I don't know what to do next. Suggestions are very welcome.
Thanks much,
Johnny
Induce the same signal into the grid of the 1st IF 7B7 and I get nothing.
Induce the same signal into the plate of the 1st IF 7B7 and I hear my expected noise from the speaker. Same with the grid and the plate of the 2nd IF 7B7. Yes! I do get my noise at the grid of the 2nd IF 7B7.
So is my signal not getting through the 1st IF 7B7? This tube has been swapped out with two other known good tubes. Sockets on "ALL" loctals have been cleaned thoroughly and I even checked continuity between pin hole and terminals of all sockets where the components and wires solder to. All is good. And of course all the tube pins have been cleaned too.
Why do I get nothing from the grids of the XXL tubes?
Once again I have to say that I have rung out all circuitry and checked all connections of components and checked that all components are good in their values etc. All IF's have been opened up and checked for proper resistance.
I don't know what to do next. Suggestions are very welcome.
Thanks much,
Johnny