JTM 45 fixed!

[cbass]

well if one of them is leaking DC It will really screw up your bias voltage.

Martin is A LOT smarter than me so you should probly be listening to him and everyone except me.

[Reeltarded]

Martin is smarter than both of us. We are probably not the best to advise ourselves on who is smart, that is how far I break the average.

[martin manning]

cb, all ideas are worth considering, keep them coming! If the odd voltage is following the tube that would argue against a leaky coupling cap.

Miles, try powering up without tubes and measuring the bias voltage on the board and voltages at all the power tube socket pins (grids, plates, screens). If you have a bias pot, measure the pin 5 voltage at min and max range.

[Reeltarded]

Will do. Thanks Mr. Martin, patron saint of amplification.

I WAS WRONG about bias following tube. Second set did the same thing and I took poor notes first time.

[cbass]

I thought he determined the problem was at the socket after trying the RFT's .Guess I need to wrk on my reading skills.My 8th grad edumacation is failing me.

At any rate yes good idea to try it without tubes

[martin manning]

So cb's theory is alive...
When measuring the bias voltage on the board, measure at the junction of the 15k and 56k, and also at the far end of the 220k's where the grid leads are connected.

[Reeltarded]

Bias corner/junction max neg .97mA, Bottom of grid feeds -22mA both phases.

Bias corner/junction min neg .97mA (???) , bottom of grids -.17mA both phases.

Ummm.. Tubes are pulled. brb

Voltage:

Bias corner: max:-61.1/min:-44.4

Bottom of grids max:-59.4/min:-44.1

[M Fowler]

Check all resistor values I had some problems and it was a 100R when it should have been a 100K resistor that caused all the problems.

Mark

[cbass]

Ummm... I think we are looking for dc voltage.I don't think mA's can be negative but I'm a carpenter not an engineer

[martin manning]

Bias corner/junction max neg .97mA, Bottom of grid feeds -22mA both phases.

Bias corner/junction min neg .97mA (???) , bottom of grids -.17mA both phases.

Ummm.. Tubes are pulled. brb

Oops, the rectifier tube must be in to get DC... Then I'm looking for voltages at these red circles.

[Reeltarded]

Added voltages ^^^^

Yes mA is neg on meter has a -. I am no mathmetician, but I know 'owe you something' when I see it! lol

[Reeltarded]

Not taken voltages at output. Those were all voltages with rec installed. brb

[martin manning]

Are the voltages at the 220k's (and grids) the same on both sides? If one of the couplers is leaking DC then they won't match.

[Reeltarded]

465 @ both, pin 4 and 6. Grids -43.9ish.

Did I do it right?

[Reeltarded]

Are the voltages at the 220k's (and grids) the same on both sides? If one of the couplers is leaking DC then they won't match.

MATCH all over both OUT sockets and on board.