[SignalOne] Re: More CX7A Drive (was:arcing)
David Bertman
[email protected]
Mon, 18 Nov 2002 11:25:36 -0800
The simplest thing I know of is the connection to RF driver board. It
LIKES to get loose. Also, though it is not the case here, I have seen
drive problems due to a blown 34 volt supply. With a system which uses
the new audio PA (like John's) the driver is the only unit affected if
this power goes.
Dave AB7B
W2AGN
<[email protected]> To: [email protected]
Sent by: cc:
signalone-admin@mail Subject: [SignalOne] Re: More CX7A Drive (was:arcing)
man.qth.net
11/16/2002 11:08 AM
Please respond to
signalone
On 16 Nov 2002 at 13:19, [email protected] wrote:
The odd thing is, using an RF diode probe, I see RF at the output of C30
on the driver board, which is variable with the drive control. Also on
the grid pin(s) of the 8072. The RF Driver transistor gets warm (not
hot) after a few minutes key down, which tells me t's not blown. Still,
no drive in the "drive" meter position.
----More-----
I checked at input and output of driver transistor. Getting excellent
amplification, voltages normal. Plenty of RF on grid of 8072, but still
acting like no drive. (i.e, no output, no plate current above resting
(100ma), regardless of "output" knob setting in Tune Position. I even
tried a THIRD tube, which I just acquired, but no difference.
It has got to be something simple I am over looking.
---
+-++-++-++-++-+ John L. Sielke
|W||2||A||G||N| http://www.w2agn.net [UPDATED]
+-++-++-++-++-+ Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
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