[Heathkit] DX-100B - spurs everywhere.

[Rick Poole]

A couple of people told me that the oscillations I was seeing on 
phone were likely neutralization, and one person told me that 
"Neutralization can be done in several well-documented ways".

So, I went searching and found a few...

http://home.roadrunner.com/~boatanchors1/dx-100%20neut.html
http://home.roadrunner.com/~boatanchors1/posting.html
http://groups.yahoo.com/group/heathkit/message/19871

... not much of anything else.

So, I tried adjusting the little wire that pokes into the PA 
compartment and managed some pretty dramatic results... now I get 
spurs on both AM and CW and they are quite readily generated.

Put the neutralization wire back where it was, no real 
improvement.  There is no position of the neutralization wire that 
shows any significant difference in behavior.

I think it always did this on CW, I just had to get the plate farther 
out of resonance on the high side before it would do it.  I can still 
tune the rig on CW and it will be stable, but I have to be careful 
not to get out of resonance on the high side (AMPLIFIER pointer 
points to higher numbers; plate tuning cap is more meshed).

One thing I noticed... one of the articles on neutralization 
emphasized keeping the grid current around 4 ma, and the DX-100 
manual cautions against running the grid current above 6 ma and 
recommends keeping it at around 5 ma.  My grid current will not go 
above about 2.5 ma no matter what, at least not on 80 meters (haven't 
tried any other bands yet).  And yet, when it is stable and putting 
out the correct frequency, I can easily get between 100 and 125 watts 
out at a plate current of 200-250 ma, just like the book says.  So I 
can't figure out why the grid current is so low.

Next step is to check all the tubes in the tube tester, and then 
wrestle the thing over to the workbench and start loosening and 
retightening hardware and checking resistor values (don't have a way 
of checking capacitor values yet).

Anybody have an idea off the top of their heads why the grid current is so low?