UPDATE to my previous post:

Gord S wrote:

I have the basic "instruction manual" and a schematic with RF
adjustments diagram......No service manual.

Problem - Unable to effect a reset of any kind. Radio "stuck" in
current configuration, and operational otherwise. Does not appear to be
in lock mode. Function button does not cause a change into function
mode (no menu's displayed etc).

Operationally - Radio works fine on previously programmed channels and
is stuck with the display in CHANNEL mode.
- Good tx output and waveform
- Good tx deviation
- Good receiver operation - DTMF operates
- Radio LCD display normal and shows channel change and s-meter bar
graph and whatever was programmed previously.
- Display does NOT show it's locked (no key symbol).

Observations - Front panel pushbuttons all cause a beep to be emitted
when pressed and a second beep to be emitted if held in for
approx 1.5 secs. Because the programmed channels work ok (DDS ok
assumed) and the push buttons all cause a beep to be emitted
(generated by the microprocessor IC201) , it would seem that that IC201
is functioning. The inability to reset or cause a change into
"Function" mode (both with a particular change of display) leads me to
wonder first how it won't reset. I see IC209 (PST9130NR) labelled RESET
and input to the processor as RESET but I don't see any control to this
other than basic ON/OFF power. IC209 appears on the schematic to be
basically a 3 terminal regulator with the output TP tagged at 4.7
vdc.......I measure 4.8 vdc (likely ok). Is this some sort of power up
buffer or delay?


Has anyone had a similar troubleshooting experience with this radio OR
knowledge of how the RESET works OR what might be locking the
microprocessor IC201? Might the EEPROM IC210 (X25160SI-2.7) be locking
IC201 (thinking about why the processor won't reset here.......perhaps
the EEPROM is disabling the micropro somehow?).


Any constructive suggestions welcomed.


Gord - VE1AJF

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I've since figured out how to gain access to the processor and
surrounding area (bend the LCD away from it's plastic cradle and then
slide the cradle up the pins allowing the display to further uncover the
board). Pursuant to suggestions and comments from Dave Dunfield, there
is no scanned input key matrix on this radio....individual pushbutton
switches pulling their respective input pins on the micropro to ground
as required - these all work (although they don't seem to agree with the
schematic which shows a variation of the processor from the one in this
radio).....trying all combinations of switches + power on yielded no
reset. Scoping the EEPROM shows that it's being accessed normally and
that the -WP pin is always HI enabling whatever the processor wants (not
locked). At this point it seems that the problem is, that, I can't get
the microprocessor IC201 to either RESET or to recognize a FUNCTION
request. It's funny that it otherwise seems to work and control the
radio correctly.

Does anyone have the service manual who'd look up the theory and
sequence of reset for either of these areas? Also looking for a
schematic which shows the microprocessor M38267M8L110FP (may be a later
model TM261A) vs the one I have showing the M38267M8L104P.

Any comments or further suggestions welcomed. As aside, I've also tried
to source a replacement front panel PCB though various Kenwood sources
who've been unable to tell me if this subunit is even available.

73 - Gord VE1AJF