[Collins] No Grid Drive

[Dr. Gerald N. Johnson]

On Tue, 2007-12-11 at 16:53 -0600, J. Dave Mayfield wrote:
> Guys my 32S1 has no grid drive, any ideas where I should start?
> 

Check in tune or key lock position. Check for plate current and power
output. PA plate current is a much more sensitive indication of drive
than grid current.

Virtually EVERY stage is involved and loss of gain in any (most often a
tube or dirty switch contact) kills grid drive.

Band switch contacts are known to not make contact well or long if not
exercised. That can be true of the grid current or ALC meter switch too.
Rocking the band switch back and forth a couple bands above and below
the band of interest often brings back drive and power output.

The ALC detector is a tube too and if it stops working the ALC meter
won't indicate.

Besides tube and switch failures, the ceramic trimmers do give troubles
with going open.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer