[AMRadio] GK500 OTA almost


Collin n4tua at aol.com
Mon Jan 2 22:26:17 EST 2017


Dear AMers,
I am having a time with this Globe King 500B. I have it ready to make RF but no modulation yet. 
Something is just not right and I can't quite put my finger on it yet. Maybe some of you have had an experience like this and might be able to lend me a hand. 
Tuning the final goes fairly well until I take it out of tune and the full screen voltage is applied to the final. Tuning is very touchy acting and reaches a point where plate current suddenly pegs the meter and some arcing/flashing happens inside of the tube. I can tame this and get it to stay stabilized but increasing loading and the plate current pegs. Any ideas?
I have cleaned and secured grounding of tune and load air variable capacitors and also disassembled each air variable and cleaned and buffed all contact surfaces. I have cleaned the final tank band switch. I have inspected every connection and contact between the antenna connector and the plate cap on the final amp. 
I will not give up!
Good Day, Collin




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