RadioBanter - View Single Post - IC-28A

Fred McKenzie · January 13th 07, 07:14 PM posted to rec.radio.amateur.equipment

In article . com,
wrote:

After several years of trouble free operation I had a strange problem
the other day; it would go "nuts" readout weird and the red TX light
was on, but no RF out. I had to do a reset with the button inside.
Being an older radio my first suspicition was the Lith. back-up batter
was due, but I measure 2.99 v. Assuming it's a nominal 3v battery does
anyone have a though where to go next? I did put it on the bench
powered up. After taking the power away (12v) and returing it a few
hours later it losses memrory.

WA7YCP-

On one hand, this sounds as if a Phase Locked Loop had become unlocked,
which might disrupt the frequency display and prevent transmitting. On
the other hand, the lithium battery should prevent loss of memory.

Other radios, both Icom and Kenwood, have 3.6 volt lithium cells. It is
possible that your radio will lose memory below 3.0, but I've had them
maintain memory when the battery was down to about one volt!

A PLL might go out-of-lock because of loss of the reference frequency
(usually a crystal oscillator) or drifted tuning of the VCO. There also
might be a low voltage regulator that has low output, often caused by a
leaky electrolytic capacitor.

Fred
K4DII