Hardware Hacking

Frequency Expansion

There are two different types of conversions that you can do to this radio.
The easiest conversion has a freq range of 26.065 — 28.755 MHz. The “PROGRAMMABLE” mode gives you a range of 25.165 — 30.105MHz.

CONVERSION VERSION 1
Remove jumper “A” from the channel board.

CONVERSION VERSION 2

1: Set the band selector to the “A” position.
2: Remove both jumpers “A” and “B” from the channel board. The Channel Display now displays letters “A” through “L” instead of a channel number.
3: Next carefully short the pins of jumper “A”. Notice that each time you short the pins the Display goes to the next letter or frequency range. Do this until you have the desired frequency range for position “A”.
4:Repeat these same steps for each of the 6 Band positions.
5: When you have completed the process, replace only jumper “B” to lock them in memory.
6: Leave jumper “A” off for the full frequency conversion.

Short description:

1.Turn on power for a minimum 10 seconds then shut off and disconnect power

2.Remove cover (Speaker side).

3.Locate the jumper pins as shown in picture, set the jumper to the required position.

4.Press the CPU reset button that is on the same PCB for 10 seconds.

5.Button back up and power it up.

Long (detailed) description:

Make sure the radio is off and disconnected from power. After selecting the desired frequency set up, press the CPU reset switch SW1 for 10 seconds.

MOVE THE SHORTING SHUNT TO THE DESIRED CONNECTION

The pic below gives a self explanitory overview of the connections and thier functions with the exception of a few notes that I will list here per connection.

CON 1: Default mode, all functions operate

CON 2: 10M and Expanded Mode. When you turn the radio on it defaults to 10M. For the Expanded Mode, press FUNC and CALL for 3 seconds. Repeat these steps to return to 10M.

CON 3: Expanded Mode Only. The frequency range is grouped in 10 bands of 40 channels each. (Letters A –J) Band “E” is CB. To switch bands QUICKLY press the CALL button. (DON”T HOLD IT DOWN)

CON 4: CB mode, operates on the regular CB frequencies of 26.965 — 27.405MHz.

Expanded mode notes:

On the Channel Display, the small number 0 – 9 to the right of the band letter is the 1KHz freq display. For instance, lets say you’re on 27.405 MHz. The Display will read 40 E5, which means you’re on Channel 40, Band “E” and the “5″ is the 1KHz position of 27.405.

In Expanded mode the RPT and SHIFT don’t work.

Talkback Feedback Fix

Modify audio circuitry by adding a 0.1uF ceramic capacitor between the “mic i/p” and “mic o/p” connections to earth on the echo/voice effect PCB, this will help to reduce RF feedback problems.

Add a 2.7KOhm resistor with a ferrite bead on it in series with the audio line after the mic gain control to reduce the audio level a touch, and adds even more filtering.

These mods seems to fix the RF feedback that plagues this chassis.

Channel Expansion

1) Open up your radio.
2) Find the small circuit board on the left of the radio.
3) Cut the green wire and tape it off.
4) There is an unplugged connector by this board….plug it in.
5) That’s it.!You now have 8 bands of 40 channels.25.165-28.755.

Tweaks

Lo Power – VR16
Hi Power – VR13
SSB Power – VR12
Modulation – VR14
Audio Limiter – TR53