[SignalOne] CX7A Drive (was arcing)

[W2AGN]

Well, I finally got the nerve up to take out the driver board, and 
replace the driver transistor.  Even though I showed "some" drive at the 
grid, it wasn't enough to budge the plate current above the 100ma 
resting.

SO, I replaced the transistor (Q4) with a new 2n5641, put it back 
together...and still no drive. I show a little RF at the output of the 
first driver transistor, Q3 (which I didn't replace), and much more on 
the collector of the new "final" driver transistor, but still not enough. 
New transistor gets warm, while Q3 stays pretty cool.

Tried adjusting R19 no difference, although does affect RF level when I 
look at it with RF probe.
Bias, Screen Voltages are good.

I even, just for the heck of it, tried connecting a little QRP transmtter 
(1/2 watt) to the grid of the final tube,...and darned if it didn't show 
drive then! So I am sure it is the driver board. Next, I guess I better 
replace the other 2N5641 (Q3). (I have already replaced C30). 

Any other suggestions?
---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS