[Heath] SB-110 VFO's

[Glen Zook]

The solid-state LMOs that were not built by TRW (not TRY) do tend to have problems tracking between the 100 kHz points.

Any of the tube-type LMOs will work fine.  Just make sure and put a 6BZ6 tube (NOT a 6AZ8) in the LMO to balance the heater strings.  The different tubes used were just to make the series parallel heater wiring balance correctly.
 
Glen, K9STH


Website:  http://k9sth.com


________________________________
 From: George Babits <gbabits at custertel.net>
To: HeathKit <heath at puck.nether.net> 
Sent: Tuesday, April 17, 2012 9:51 AM
Subject: [Heath] SB-110 VFO's
 
Digging deeper into the SB-110 and found out that the VFO is not the original one with the 6AZ8.  Looks to be solid state and marked on top TRW-800668 and 110-48.  That explained the two loose wires behind the panel (B+ and bias for the original VFO) and why the white lead goes to ground through a 3.9 ohm resistor (replacing the original tube filaments).  So one mystery solved anyway.

From my reading it looks as if this VFO came from the SB-102 or SB-303 sets. I have read some unfavorable things about the HeathKit solid state VFO's recarding tracking.  But it seems like all the negative information is prefaced by "HeathKit VFO's were not made by TRY.

Anybody on the reflector have any ideas?

Thanks,
George
W7HDL

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