GE-MPL or M-PA, or P400 Portable
900 MHz MTL (or M-PA) portable radio, an get it operational on the 
902/927 Amateur Band with minimal effort and NO hardware mods.


The 900 mhz MPA (full numeric keypad) does 902-927 split repeaters 
(I have a hacked RSS for it), but has no "talk-around", and programs 
via a GE TQ-3370 RIB or Price Industries ribless cable?

Also the same radio will work with the Hamflash installed (fully
keyboard programmable), both tx-rx in the 927mhz range, but won't work
the 902-927 repeater split but will work the 12mhz split if you perform
an extensive set of mods that include removing a VCO pack from another
radio and installing it in the MPA, along with some other changes.

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M-PA 900 MHz Modifications

Basically, the 900 MHz M-PA is made from an EDACS 900 MHz M-PA by
loading the M-AH software into the flash memory on the M-PA logic
board. A speed up of the synthesizer section is required, Follow these
instructions:

1-Change U15 from a P3 VCO to a P1 VCO (as used on the original TMX
mobiles). Tack solder the new VCO in place to test the range for
proper operation, since some P1 VCO's do not cover the ham repeater band.

2-Change R45 from 47k to 68k. Check the output of the Q11 regulator
circuit. It should be approx. 6.0 volts after the resistor change.
Adjust the value of R45, if necessary. If it is less than 5.9 volts,
the VCO may not operate in the repeater band. If it is greater than
6.1 volts, the regulator will not properly regulate and transmit hum
and noise will result.

3-Remove R54 and jumper across R39 and R40.

4-Break the VCO control line between Q8 and R22. Add a silicon diode
with the cathode end attached to R22. Place a 22uF tantalum capacitor
across the diode (positive end attached to the anode). make sure that
these components do not short to the casting when assembled. Use a
physically small capacitor (4v or so).

5-Add a 10k resistor to ground at the cathode end of the diode.

6-Cut the trace from the emitter of Q8 going to U9 pins 1 and 8.

7- Connect U9 pins 1 and 8 to the cathode of the diode.

Notes:
The control line voltage (emitter of Q8) should be above 1.2 volts for
consistent PLL locking at the lowest desired transmit frequency. This
is dependant on the specific VCO used. The synthesizer may not lock
when going from transmit to receive if the control voltage is too low.
The VCO bandswitch line is always low in receive and high in transmit
modes. This allows the radio to receive down to about 915 MHz and up
to about 935 MHz. Transmit will cover from about 908 MHz to about 940
MHz. Note that the receive sensitivity is poor below 918 MHz due to
the receiver front and filters.

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MPA Ham Code release levels

Any chance there's a copy of the hamflash source code around??? 

> No,,, the radio was discounted  in 1999 and the last flash code was 
>written in, 1999, the last 'HAM flash was written in 1997, shortly after 
>that the author left the company...he retired and moved to the west coast