HW and SB vernier drives

[Kees & Sandy]

In light of some of the comments about tuning dial
deficiencies of some of the Heath receivers/transmitters/
transceivers, I just completed some backlash, stiff tuning,
slipping adjustments of the vernier drives and wonder if
there are any other suggestions.

I relubricated the drives by forcing grease into the drive
mechanism .....fill the coupling with grease and (with the
set screws in place) insert a section of 1/4" shaft until
grease comes out the front.

There was still stiff tuning and backlash at one end of the
dial. Turns out the problem is interference between the hole
in the front panel and the outside of the first Jackson Bros
vernier drive, which causes lateral binding between the two
vernier drives. You should be able to loosen the setscrews,
remove the knob, remove the two flange mounting screws,
and readily pull the vernier and it's mounting flange out
through the front panel ....if you can't, you have interference
between the hole in front panel and the outside of the first
vernier. Double check this by removing the vernier from the
flange and insert the first vernier onto the second vernier
through the hole in the front ....there should be some lateral
"play". Alignment is controlled by the four VFO mounting
lugs (I found the ones under the cable missing on one unit),
the two screws mounting the vernier to the flange, the two
screws mounting the vernier flange to the front panel, and the
location of the front panel itself. On a HW-101 the only way
to obtain alignment was to loosen all the front panel controls
tied to the chassis, loosen the two screws at the top, and
reposition the panel slightly. Works great.

I suppose another method would be to increase the diameter
of the hole in the front panel slightly, but that's more work,
probably end up scratching the front panel, and is really not
necessary.

If the dial itself is too loose, tightening the three clutch screws a
little (1 turn or less) is a good idea. Apparently the plastic
reshapes itself a little over time.

73s Kees K5BCQ

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