[Heath] SB102 Main Tuning Knob And Friction Wheel

[Glen Zook]

No "O" ring on the mechanism that turns the LMO in any of the Heath SB-Line equipment.  The friction ring sits so that there is one portion on each side of the inner ring of the dial.  This is adjusted by moving the assembly up, or down, on the inner ring.  The adjustment is correct when the dial can be turned through a full 360-degrees without slipping or binding.

It sounds like someone tried to use an "O" ring to provide friction instead of properly aligning the drive. 
Glen, K9STH 
Website: http://k9sth.net

      From: Rich Sahlender <wa3wlh at comcast.net>
 To: heath at puck.nether.net 
 Sent: Thursday, May 31, 2018 11:33 AM
 Subject: [Heath] SB102 Main Tuning Knob And Friction Wheel
   
Hopefully the following will make sense to those of you familiar with
the SB102 VFO and the curious "friction?" method used by the main tuning
knob to actually tune the VFO.

I acquired a SB102 on which the VFO main tuning knob was spinning without
moving the VFO. The old ragedy manual that was provided with it is useless
as the pages related to how the mechanism works are badly worn and / or
missing. So until I can get a usable copy of the manual I am winging it.

I pulled off the main tuning knob and found that the "friction?" wheel on
the stud that the knob installs on was not making contact with the
"ring?" on the VFO mechanism itself. Curious design. Anyway it looks
like there are remains of an old disintegrated o-ring originally on that
wheel. Is there supposed to be such a ring to provide the friction with
the VFO?

The two "plates?" that make up the friction wheel are snug but not so
much that they cannot simply be pushed down onto the ring attached to
the VFO mechanism so that the ring slips in between the two plates. So I
went ahead and did that and it now tunes the VFO just fine but... should
it be left this way to operate or should I be looking for an
appropriately sized o-ring to slip on the wheel to provide friction with
the ring in the VFO mechanism?


   
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