[Milsurplus] T-19 Update

[Mark K3MSB]

As posted earlier this year I’m working on my first T-19 project.



I started testing it this week, but there are a few issues that I’m
stumbling with.



Here are my voltage measurements:


Oscillator Voltage OFF

          Key Up   Key Dwn

Plates:   550       440
Screens:  550       275
Grids:      0       -18 DC
            0       0.1 AC

Oscillator Voltage ON

          Key Up   Key Dwn

Plates:   550       510
Screens:  550       150
Grids:      0       -40 DC
            2.1      2  AC

As you can see, the screen voltage is about 100V too low under key down
conditions.  R-90 and the 20K tap resistor in my power supply (as per Dave
Stinson) measure OK.



I’m wondering if C-64 could be the issue;  I was going to unground one end
of it to experiment;  I can’t see any danger in dong that.



I’m getting about 1W out of the transmitter.  Antenna Coupling is at max,
and Antenna Inductance is almost 0 (expected).



I’m using a small air variable cap at the output of the transmitter to give
me a series capacitance of about 50 pF,  the other end of the cap goes into
an SO-239 which goes to a W-4 Wattmeter and finally into a Cantanna Dummy
load.



Any suggestions?



Thanks



Mark K3MSB