I regularly experience the same problem when tuning, and I put it down to
changing the frequency whilst the channel was receiving a transmission,
but I haven’t confirmed this is the case.



And another problem…. After 4 years of private use since new, my AR4201
developed a low voltage fault which showed up when attempting to transmit,
(flashing display). After checking the voltage at the connector was normal,
and after several hours of head scratching, I concluded it had to be the
Becker radio itself. A Becker avionics repairer, advised me to check the
aircraft wiring. I was about to give up, and whilst switching the unit off
with the on/off switch I noticed the voltage display vary sometimes up to
normal instead of from below 9.5 to around 10.5. I did this slowly a few
more times, and was convinced the switch was at fault. The avionics
repairer now has the unit, and confirms the fault. Not very durable
considering private use only, and not too cheap a repair I might add. He
suggested using an avionics switch!



Phillip