Modifications for the Kenwood TM-411



19-07-1998 TM-411 Low/No Receiver Sensitivity

2-14-85

Some users of the TM-411 have reported a loss of receiver sensitivity.
This may occasionally be traced to a loss of oscillation in the 2nd Oscillator, L29, on Unit A. Changing the below listed parts should correct anly loss of sensitivity due to problems in the 2nd Oscillator.

O A Unit (X44-1600-00) change the following parts:

XTAL L29 to L77-0873-05
C15 to a 1.5 pf cap.
C54 to a 33 pf cap.

Time required for this modification is 1/2 hour or less.



23-04-2000 TM-411A Microprocessor change
Author: Kenwood Communication, inc.


Service Bulletin no. 1041 (10 February 1994)

Symptom:
Due to a recent rule change by the FCC it is no longer possible to supply transceivers, or provide replacement microprocessor that would allow a transceiver to receive in the 800 MHz band.

Corrective action:
The microprocessor program of IC5 has been modified to prevent 800 MHz band reception. Production has been changed beginning with serial number lot 510xxxx. Units produced after this point will not be capable of 800 MHz reception.

Parts required: 

Qty   Description                Old part No.      New Part No
 1    Microprocessor             75116GF-E83-3BE   75116GF-J19-3BE

Procedure:
When ordering a replacement microprocessor you will be supplied with the new version. Please make sure your customer understands the limitations of this new