DX-60A

Yo!

I'm restoring a really nice Heathkit DX-60A. I finished cleaning and eliminating all the kooks. She is REALLY beautiful. So I hooked up the 75 watt bulb, worked it up to the full 150 ma and all. The power supply is perfect. Using a crystal for 3885 into the dummy load was perfect. The bulb was lit hot and straight ahead. Been there many times before then....... Then came a bit of smoke. Looking under the chassis I found the choke from the bias to the 6CL6 driver slightly toasted. It still registered at about 28 ohms but I'm not sure what it should have been to start.

After that it was run-away grid drive. I'm replacing the choke of course. The resistor was supposed to be 18K. It was 23K. A new one is on order. There is a bypass .005 disk between the 18K, RF choke and ground. That is being replaced as well.

Here's my question: is the unstable grid current a result of the 6146 not being neutralized or my stupidity tuning? If the new parts don't work, what should I consider next? I know I binked that stupid stub neuter thingie in the final cage. Anybody have a DX-60A manual? LOL!

I want one to pass on when this xmtr is sold. I have a straight DX-60 book. The componants in the driver stage correspond to the manual so that circuit was not changed when the model was upgraded. I can fire up the B to the same instructions so that never changed. My DX-60B-based set of all three units including VFO and HR10B is very close to mint. That's what happens when us seniors go back to their dream rigs. Hey, might be better than sex!

I go back to the early '60s as a Ham so I know a lot but never enough!

Mike - W9ZSL - 73!

I will be selling this beauty eventually but I want to get it working so I can compair it to my marvelous DX-60B. Paid $500 for the bugger and yes, it was worth it.