HW-101 dial drive slippage

[rayfri]

Ed:
i dont think the second part that you mentioned is a problem i'm having.
the frequency is very stable on mine...   the only problem i'm having is about
the same as the other guy mentioned.   when i turn the dial knob, there are
several places where the knob will turn, but the dial mechanism won't.  The
frequency won't change either when this happens.  the knob just turns, and after
several revolutions, it will "grab" again and the frequency dial will move for
about
half a turn maybe, then stop again until I go through several more rotations... so
essentially it takes about five dial turns to get the dial mechanism and frequency
itself to change any significant frequency change.
     i have tried the suggestion of taking the tuning knob off, and loosening the
nut and pressing down (I think I was told downward push) to tighten the
mechanism...   There was no appreciable or noticable change....
Ray  wa7itz


Ed Kotkiewicz wrote:

> rayfri wrote:
>
> > would that be the same problem I'm having with my sb 100?  his symptoms
> > sound almost identical to what i'm experiencing...
> > Ray wa7itz
> >
>
> EK> Ray, the SB series uses an LMO (as opposed to a VFO) and a different (less
> positive) method to couple the dial action over to the LMO.  Two conditions
> happen with the SB gear.  First off the dial is regulated by a split washer
> (beryllium) assy that has two washers that are flaired out on the ends and are
> assembled, back to back, to form a pulley.  This pulley then engages the inner
> ring of the actual dial.  If you take off a SB's tuning knob you will see a nut
> holding the shaft assy.  If you loosen (not remove) this nut you can slide it
> up or down, which engages the inner ring of the dial.  As you push (lightly)
> downward, the dial ring is engaged by this back-to-back pulley and a friction
> fit occurs.  Sadly, as time goes by, the these washers spread apart and the
> friction fit becomes less reliable.  You can take the shaft nut off, lift the
> shaft assy away from the dial and take it out through the back.  Now unscrew
> the screw that is on the backside of the assy., carefully remove the washers.
> You now want to re-flatten the surface to make the washers flat again.  Do this
> very carefully.  Then re-install the washers back onto the shaft, put the assy
> back onto the faceplate and reattach the shafts nut.  Slide the washers back
> onto the dial wheel and make a snug fit.  Then tighten the shaft assy nut and
> you should be back in business.
>
> The second part of this problem is a bit more difficult.  The way I do it is to
> remove the LMO from the radio.  With the LMO removed and all the dial stuff
> removed, look at the LMO from the front and down in the lower left area.  There
> is a shaft coming out of the LMO.  It has a collar that is held in place by a
> very small allen set screw.  Remove this collar.  Look carefully behind the
> collar and you will find 6, interlocking leafs.  Carefully remove them, one at
> a time and set them on your bench.  When you have the last one out, start
> cleaning them.  I use a small propane torch and remove as much of the embedded
> grease as possible.  Then recoat each leaf with a black moly-lube and
> reassemble the LMO.  I would only do this if you are having drift with staying
> on freq.  The petroelum based lube has lost its lube properties and when the
> radio is cold the lube solidifies.  When you turn the radio on, the lube slowly
> starts to loosen up and bingo, you have station drift.
>
> Heath devoted a number of pages in the SB manuals just to that dial interface.
>
> Good luck......your mileage may vary.
>
> Ed
> Husband of a "Former Ham at Heath"

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html