[Collins] 32S3 tuning problem

[Dr. Gerald N. Johnson]

On Fri, 2008-09-26 at 18:22 -0500, Jaime Gomez wrote:
> I am in the process of recovering all my equipments after over 8 years
> working offshore.
> I have found a problem with my 32S3.
> When I put it in tune, the plate dip corresponds with the max output, but if
> I change the output to lock (full output), the max RF output is way off the
> dip in plate current. I am testing it with a 50 Ohm dummy load. I have gone
> over the neutralization procedure and it is as specified in the manual.
> I wonder why might this be happening? Any hint?
> Appreciate any help
> Thank you, 73,
> 

My 32S-3A manual has an added paragraph g in the feedback neutralization
section and addition to paragraph e. 

e. "Adjust feedback neutralizing capacitor C55 (below chassis) until the
pa plat current dip and th grid drive dip coincide. Readjust the I Gain
as necessary to hold pa grid drive to midscale during this adjustment."

g. "Check that pa plate current dip and pa grid drive dip occur at the
same setting of P.A. TUNING control."

PA and driver neutralization require breaking the plate and screen or
heater circuits for the driver) to prevent the tubes drawing any
current, else the tubes being neutralized will have a little gain and
neutralization will be inaccurate. I don't like the suggestion that a
different driver tube with one heater pin cut off be used to set the
driver neutralization. The whole purpose of the adjustment is to account
for variation between tubes.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer