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 <[EMAIL PROTECTED]> or <[EMAIL PROTECTED]>. Charles Charles A Taylor, WD4INP Greenville, North Carolina _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
