[TenTec] Model 1220 memory glitch

[rohre]

Sounds like the wiring to the 9V back up battery is picking up a transient
that is coupled to the microprocessor memory as a reset pulse.

Make sure the mounting of battery and dressing of leads does not have  them
too close to power to rest of circuit; that the switch is not arcing, (look at
its contacts with a scope during the switching process,) and make sure that
all the specified bypass capacitors on the power leads are working.  Try
bridging another new cap about 10MF across the 9 volt battery bus where it
joins the circuit board.  Check the operation instructions to see if you are
supposed to hot switch power like that; normally, I would not change a power
level switch while something was transmitting, that is a pretty severe
transient demand on any system.

Good Luck, and if all else fails call Ten Tec service dept. Maybe they have a
new batch of components that is causing this some way in the kit.

Stuart K5KVH

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