[ARC5] T-22 Woes

[Mark K3MSB]

Hi Guys --

I've got a working T-22 down here and one that isn't working; the non
working unit is stumping me.

The working one is putting out about 40 to 50 watts via a series 67 pF
capacitor to a 4:1 UNUN thence onto a dummy load.  The non-working one is
putting out nothing into the same output network, and I think the problem
is in the screen circuit.

Voltages for the working and non-working T-22 are pretty much the same
except for the screen voltages on the 1625s.   The non-working one only
develops about 200 to 220V on the screens while the working on has about
300V.  The Grids of both are about -50V as expected.

R-90 is 540 ohms which is a bit low.  I tacked in a 680 ohm resistor, as
well as  replaced C-64, with no results.

Since I'm getting -50V on pin 4 (and also the hot end of R-74),  that tells
me I'm getting sufficient drive to the finals.

With a pickup loop on the finals, I can tune the output coil to resonance
but not enough to move the watt meter.

The oscillator waveform on the non working unit appears to be not as good
as the one on the working unit.  Also, I can hear the oscillator of the
non-working one on my Icom, and it doesn't sound pure.  I don't know how
else to explain it.

So, I think I'm getting sufficient drive,  I've replaced R-90 and C-64, and
I'm still getting only 200 volts or so on the screens.

I do have continuity between the tap on L-52 and ground.

Help!

73 Mark K3MSB