SB100 belts

[Stewart D Lyon]

Hi Gang:

On the subject of belts for the preselector and loading capacitors for the
SB100 (et al), I have found several different ways to go. Although Heath
supplied three belts of the same type for both the preselector and the
loading capacitor, I recommend a  larger belt for the loading cap to lessen
the strain on the front bearing of  the cap.

 First off are o-rings - available from several different manufacturers -
which use a standard "dash number" system to describe the various sizes.
For the preselector use -227 which is 2.11"ID and 0.14" wide and for the
loading cap, use -228, 2.23" ID and the same width. (1/8" width will also
work.)  These belts can be found at appliance repair stores, sometimes ACE
hardware stores, plumbing stores and auto race supply stores. I got mine
free from an aerospace type place so I don't have any price data.

VCR drive belts work.  They are a flat belt (instead of round) and are
dimensioned by circumference.  They are also "stretchier" than o-rings so
they don't give quite the preciseness of control - also they can be shorter.
For the preselector, try a 64 (6.4" circumference, 2.04" ID) and for the
loading a 70 (2.23" ID).  I've seen these belts in radio stores anywhere
from 99 cents to $4.59 ea. If in doubt, use a piece of string or hookup wire
around the pulleys to get the circumference and subtract about 10%.

Phonograph drive belts also work and were what I used in the 70's.  Not many
phonographs around anymore so they may be hard to find.  Try a radio store
that's been in business a long time.

Multi-Volt Murray suggested cutting the length you needed from stock 1/8"
material and gluing the ends together.  I've watched technicians at work do
just that and it looked to me akin to brain surgery and not something I'd try!

BTW - using o-rings for belts was done for years and is not a Heath idea.
The Mil-spec o-ring places have a special mix just for drive belt use.

Hope this helps someone.  Stu - W6CUX
S. D. Lyon, Space Vector Corp.
email: slyon at spacevector.com
Phone: (818)734-2610 or (818)886-6500
FAX:   (818)886-3947

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