[Boatanchors] RE: SB-102 LMO

Mon, 24 Jun 2002 12:59:41 -0400

Glen, as an ex-Heathkit service technician, I can say that the solid-state
LMOs tracked very closely across the band. I've seen 'em out by a few
kilocycles, but never by ten kHz! My old SB-303 LMO, and its companion
SB-401 LMO, are still tracking well across the bandspread, although errors
are more noticeable now than years ago. But they're still well within the
ability of the cursor adjustment at 100 kc. points. Worst-case errors seem
to be about 3 kHz, but most errors are 1 kHz at the cal points.

== Vy 73, AI2Q, Alex  .-.-.

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Glen Zook
Sent: Sunday, June 23, 2002 11:09 PM
To: [email protected]
Subject: [Boatanchors] SB-102 LMO

I am in the process of trying to get an SB-102
repaired for a friend and the main problem is the
solid-state LMO.

I now have available a total of 5 LMO units, of two
different physical layouts, but are for the SB-102.
All five of them when the "end points" are "on" (that
is exactly 5 revolutions goes from 5 to 5.5 MHz) the
intermediate 100 KHz points are off from 3 to over 10
KHz depending on the individual LMO.  This has been
checked both with a frequency counter and in the unit
itself "on frequency" (i.e. 3.5 - 4.0 MHz received).

Now, nominally, Heath LMOs are well within 1 KHz at
the intermediate 100 KHz points.  At least this is my
experience with the tube type units.  However, my
experience with the solid-state LMO units is minimal
(have worked on numerous tube-type LMO units).  Since
this trait is the same on 5 different units, I am
wondering just how close the "tracking" is normally on
the solid-state LMOs.

The physical differences between the two types is
considerable.  Primarly the only things common are the
tuning shaft, the 3 terminal power strip, and the
ridge for mounting the upper portion of the dial
assembly.

Frankly, since all 5 units show the same type of
problem, I am really wondering about the tracking
ability of the solid-state LMO units.  Of course
Murphy never takes a vacation, but it is strange that
5 different units have the same problem.

Any ideas?  Any suggestions as to how to get the
frequency to track closer (yes, I know that the
slotted variable capacitor plates can be adjusted - a
real pain!).

Glen, K9STH

=====
Glen, K9STH

Web sites

http://home.attbi.com/~k9sth
http://home.attbi.com/~zcomco

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