[Drake] T-4XB--no output

[Paul Ellis]

Frank,

Thanks for the note!  There is no plate current beyond bias being indicated.

>You did not mention anything about plate current.  Is there any plate
>current?  Can you dip the finals?
>
>Now, before you try that I would suggest removing the RF cage and
>inspecting the parts before doing any more tests under power.

I have it apart on the bench and have checked for stuff touching in the RF 
cage. I haven't checked the output cap yet, though.

>Clearances inside the cage are pretty close.  Make sure nothing is
>shorting to ground and that everything is mechanically solid.  Nothing
>broken or flopping around.  Use an ohm meter and check all the points of
>HV and RF to make sure there are no shorts.  Check the plate RF choke to
>see if it is open.  Make sure the output capacitor is good (not open or
>shorted).
>
>Then do the same under the chassis for the drive circuitry.
>
>Connect the ohm meter across the loading capacitor and tune it through
>its range to see if there are any shorts.

Still need to try that.

>Check the transmit relay coil and contacts.  If the relay does not
>close, there will be no Rf output.

I need to check that more closely. I did apply DeOxit to the relay contacts 
and tried rubbing a De-Oxit soaked piece of paper across the contacts.


>You might also check the wattmeter to make sure it is working properly.

Check.

> >From your description it sounds like the driver may be okay.

I have the feeling that it is, too.  I need to go back and check the 
circuit between the driver plate and the final amp grids more thoroughly. 
The resistors all around the finals and driver check out within spec with 
the DMM, but that's in-circuit. I'll try unsoldering resistors next to try 
verifying that those resistors are all right.

>Regards,
>Frank Kamp

73,
Paul