HW100 nightmare

[Dick KF4NS]

Just a quick update. I actually made some progress finally. The 
trouble with the instability in the HET OSC was cured by simply 
replacing V19 12AT7 again, with a Motorola instead of the no-name one 
in there that tested great. A good example of the tube tester not 
being the ultimate determination.

To quiet down the chattering relay every time I tried to load on any 
band, I replaced the relay amplifier V12 IEC brand with a PRO/COMM and 
now I can tune all bands except all 10M bands which still only give 
10W out if I am able to load it at all.

While looking into all the suggestions I decided to check everything 
again in the finals. Everytime I touched V8 (not the juice, hi,hi) the 
plate current pegged the needle. I turned it over and found pin 6 
(cathode) to be intermittent. I cleaned the socket again and bent the 
pin terminal inward and that problem is solved.

I still cannot get the plate meter to read correctly. I must leave the 
bias adjustment full ccw to get the -65vdc in receive and -62vdc with 
the rig keyed with no drive. I replaced the two bad meter resistors 
and the 2 cathode resistors. Something is really screwy in that darn 
bias circuit.

I have checked and double checked all the areas that are common 
trouble for 10M. The other bands all load without any frequency error 
but on 10M I cannot even read a constant frequency and the relays 
chatter constantly. I checked the B+, LV and bias while the relays 
chatter and all dip just a bit using my VTVM.

That is all for now, I am still re-reading all the bulletins. Receiver 
section still works great.

73, Dick KF4NS
St Petersburg, FL 33714 USA
Keep The Glow! 

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