Date: Mon, 24 Nov 1997 14:41:39 -0800 From: Stewart D Lyon To: HEATH@LISTSERV.TEMPE.GOV Subject: SB100 belts 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@spacevector.com Phone: (818)734-2610 or (818)886-6500 FAX: (818)886-3947 --- --- --- --- --- --- --- --- --- --- --- --- --- --