[IRCA] field modification to Space Magnets 1 and 2

[Charles A Taylor <MWDXer@xxxxxxx>]

Anyone who owns one of Joseph Worcester's SM-1 and SM-2 Space Magnets
(which I gleefully call Space Maggots) should read this.

After working on three of the SM-2s, I had this problem common to all three:

At times, especially with a new 9-V battery installed, the Space Magnet will
break into uncontrollable oscillation.

The problem is that Joseph used germanium transistors in the first stage of
the loop amplifier, and earlier germanium transistors "age" in such a manner
that their gain rises. After a while, it rises so high that the circuit
oscillates intermittently.

A good permanent "fix" is to change the collector resistor of the first
stage (which has the germanium transistor) from 2,700 ohms to 4,700 ohms.

If anyone has this problem with their "Space Maggot" and wishes me to fix it,
please contact me directly at <MWDXer@xxxxxxx> or <WD4INP@xxxxxxx>.

Charles




   Charles A Taylor, WD4INP
  Greenville, North Carolina 


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