TM731A.3

Subject: Kenwood TM-731A firmware bug

The Kenwood TM731A dual bander has a firmware bug that breaks the 2m VFO scanner
in certain circumstances, that is, the 2m VFO scanner won't work properly if
certain PL tones are stored into memory 1.  So far, all tested 731A's have had
this problem.  The highest serial number tested was 72713.  To demonstrate the
problem, perform this experiment:

1. If not already done, load search bounds into memories A and B of the 2m
    unit.  Verify that the VFO scanner works.
2. Change the PL tone for memory 1 to (for example) 91.5:
    select memory 1, press F VFO to transfer it to the VFO, then
    press F TSEL and select 91.5 Hz PL tone, then store back into
    memory 1 by pressing F MR.
3. Set the VFO to a frequency outside the range given in memories A and B,
    then start the VFO scanning (by pressing VFO for a few seconds).
4. If your radio has the bug, it will alternate between the frequencies
    stored in memories A and B.  If you start the scan while the VFO
    is within the search range, it will scan up until the top limit
    is reached, then begin alternating between the two limit frequencies.
5. To restore 2m VFO scanning, program memory 1 with one of the several PL
    tones acceptable ... the default of 88.5 Hz works fine.
6. The 70cm unit does not appear to have this problem.
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73 de James Dugal, N5KNX @ W5DDL (70504) or jpd@usl.edu.