[AMRadio] Heathkit DX-60 grid current drops

Larry Szendrei ne1s at securespeed.us
Thu May 27 12:36:24 EDT 2010

As Jim says, you may be losing drive to the final grid because the drive
signal is going away. But that's not all that can go wrong. Make sure the
final grid bias resistor hasn't drifted off-tolerance or changing value as
it heats up. If it is, replace it. I have also had bad final tubes (pair
of 6146s in a DX-100) create the symptoms you describe. Originally I
thought for sure the problem was with the drive signal, but that wasn't
what it turned out to be.

73 es GL,

> Brian the final is losing drive from the driver/buffer/VFO.  Check all
> tubes first then if that doesn't fix it you will be troubleshooting
> under the chassis to find out what components may be changing value.
> Jim/W5JO
>> My Heathkit DX-60 grid current drops after a couple of minutes and
>> will keep dropping more rapidly as I increase drive level. Eventually
>> the tube plates glow red. I am tuning by the book.
>> Any ideas?
>> 73
>> Brian

Pay a visit to my amateur radio web page at:

More information about the AMRadio mailing list

This page last updated 17 Jan 2018.