DX-100 help needed

[Brian Wood]

I have nearly finished the restoration of the DX-100 I bought recently, and
it looks really nice. The re-plated/lacquered copper chassis really shines!
Putting it back together was *almost* as much fun as building a Heathkit
from scratch. I turned it on for the first time today and started adjusting
it! It puts out a signal, but there are a few problems I could use some help
on:

1. Although the drive is adequate and the plate voltage on the 6146's is
correct, the output is very low (40W RF out on all bands). I suspect the
6AQ5 clamp circuit is reducing the 6146 screen grid voltage too much (it is
only reading about 70 volts), which seems kind of low for a 6146 which has
screens rated at 250V. I have adjusted the bias pot but to no avail. Also
tried 2 sets of 6146 tubes that all had good output on a Hickok tube tester.
The manual doesn't say what the screen voltage ought to be, but on my
homebrew rig it has 185V on the screen. Can I just pop that tube out to see
if it helps?

2. The loading cap doesn't have much affect at all. I can see that it is
hooked up correctly, and I'm feeding my beam with the rig, so it should want
to have some loading. My homebrew 6146 rig has a pi-net output like the
DX-100 and it loads up fine into the beam. This rig has the DX-100B loading
cap mod that replaced the coarse/fine loading with a single 365pf variable.

3. Not that it's any great loss, but I can't get any output out of the VFO
on 11M.

4. What's the deal with that dial? There are two 40M bands. I got the one
that has 40/20/15/10 to work, but the one that's on the same section of the
dial as the 160 and 80M bands doesn't do anything. I'm guessing this is
because they used the same dial as the VF-1 which had a switch that covered
160/80/40 or 40/20/15/10 or 11, so it is simply not used on a DX-100. But
the manual doesn't say. Anyone know?

Could also use a handful of new knobs.

Any DX-100 experts out there?

73,

Brian, W0DZ

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