[Heathkit] SB-102 mods

[Drew P.]

Paul wrote:

"Have encountered several modifications to an SB-102
Not being intimately familiar with the 101 / 102 I am asking group for
anyone recognizing the mods and their possible validity
#1 An extra trim pot in series with the original S meter zero. There are
several other resistor changes as well."

My SB-101 had a similar modification.  The S meter would not zero.  I believe that the pot was a kludge to atempt to compensate for a circuit fault. The actual fault was that one of the 100k resistors in the s metered IF amplifier's screen circuit had opened. Replacing the open resistor, replacing the out-of-tolerance other 100K screen circuit resistor, and removing the mod restored setability to the s meter zero.

Many 100k resistors and many other high resistance resistors in this radio were way out of spec, 500% and more and some outright open.  This caused a number of faults.

"#2 An added trim pot added to the board near V19. Turning the pot changes
the frequency."

I am not familiar with this one. Perhaps it is to add RIT?

Drew