[ARC5] 12V power pentode - some details.

[Kenneth G. Gordon]

OK, Gang, after some questions from you folks, and despite my answering some of 
those, I thought I would fill you in on the details as they exist in my mind.

All of the ARC-5 stuff I have had were receivers. I was "gifted" 150 of them by an old 
employer (1970s) when he died. I sold all the good ones off, and kept only the badly 
chewed up ones, all of which would require considerable effort to get operational, let 
alone restored to factory condition.

As far as transmitters were concerned, I had none.

Some of the kind folks on this forum, at my request, sent or sold me at a very low prices, 
several unrestorable, most badly hacked up, transmitters to experiment with.

I've seen a lot of discussion here about putting the transmitters on the air, and one of the 
common complaints is poor keying quality.

I thought that perhaps by changing the 1626 triode oscillator to a correctly-sized 
power-pentode in the ECO configuration, much of those keying issues could be fairly 
easily resolved.

Thus my question about an octal 12V power pentode.

I believed, and still do, that a very simple change at the 1626 socket, and a good power 
pentode would be fairly easily implemented.

Trouble is, there ain't one.

I think at this point, I'll use either a 6AG7 with a resistor, or a 12BY7 and an adapter to 
continue my experiment.

The subject is a 7 - 9.1 MHz bare aluminim transmitter which has two SO-239s mounted 
on the front panel, a key jack, also on the front panel, an octal plug on the back panel, all 
the original wiring ripped out, extra but empty holes in various places, a shaft and knob 
sticking out of the side connected to the  front tuning capacitor, the roller coil removed, a 
piece of aluminum plate covering the front where the roller coil was, and a two section 
BC variable mouted in its place, and the final tank circuit modified for what looks like a 
pi-net output. 

I plan to use some JB Weld to plug the holes and otherwise put it back to as close to 
original as possible, but want to change the VFO to see if I can easily improve the 
keying.

I'll run it on a dynamotor from a 12 V battery.

Anyway, that's the story.

Thanks for all the suggetions. I very much appreciate them.

Ken W7EKB