1995 E420 with a Becker Radio

When the car starts, there is a beep from the left speaker, by the steering wheel.
1) turn key to on (dash lights up)
2) wait 2 seconds, then there is a beep for 1 second
3) this occurs with radio powered on or off

Looking to investigate if the beep occurs with the radio head removed - but challenged with parts

There are no other symptoms, and the car seems to run fine. The radio works fine after the beep. The beep comes when radio powered on and powered off.

Many thanks

__________________
Thanks for the help
Bill Fisher

'86 560SL (186K) - Now a 'classic' : Registered as an Historic Vehicle
02 E430 in the stable
'14 LS460 (Lexus)
- - - - -
'95 E420 (198K) found a new home
'99 E320 (80K) (gave it's life for me as we hit a bumper)
'95 E420 (231K) Sold to a happy buyer, new to Mercedes
'90 300E (65K) Sold to an Mercedes Lover
'92 190E (215K) - retired to the salvage yard
'93 500SEL (214K) - Moved to another family, still runs like a young pup