* Hook up radio to power and turn on for a minimum of 10 seconds.
* Turn off radio and disconnect from all power sources.
* Remove Bottom cabinet cover.
* Locate Diode D2 on the vertical Front Panel PCB (see image below), this is the only Non-Surface Mount component found in this area.
*Clip or remove (unsolder) Diode D2.
* Reset the radio CPU by temporarily shorting the two front panel circuit board pads (see below) located near & just right of Black Potentiometer.  
* Hook the radio back up to power and turn on the radio.
* Press the FUNC button, then press and hold the CALL button for approx. 3 seconds. The frequency and band indicator ( A-J) will appear on LCD.
* Tap the CALL button to select bands A through J.  FCC CB frequencies are on band E.
* To switch between channel and frequency display, press the FUNC button and then press the CALL button.
* When turned off and on again, the radio will always default to original 10 meter settings. 
* To automatically return to last used frequency and mode, simply tap #4 button or press the FUNC button and then press and hold the CALL button for approx. 3 seconds.

 

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Enabling Full Band Mode, Version 2

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This version of the mod was sent to me by Bookworm, thank you.

I have an addition to your magnum 257, Roadmaster Titan II, etc. mods page.

I recently aquired a Titan II and all I had to do was find the four pins at the (conv1) location on the board and jump them (1&2,3&4).

thanks..bookworm

 

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A quick way to change bands, sent to me by Cris

For the Titan II, Black Hawk, AE845, Magnum 257 & 357

Instead of using the func switch and the holding the call button for 3 seconds, program into memory a channel in 11 meters or use LCR. quick and easy.

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Enabling Full Band Mode, Version 3

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This version of the mod was sent to me by Andy, thank you.

In reference to the Magnum 257 mod, I just got a new one and there's been a slight change. There is now a "reset board" inside the radio that contains a reset button so you don't have to short out the board to reset. Also, the diode that you clip to get extra frequencies is no longer there. There is now a jumper on the reset board. You move it from CN1 to CN3 and it opens the frequencies, no cutting/soldering required!

The reset button and jumper are the only differences in the mod, everything else remains the same.

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Possible conversion info, not sure it is for this radio, but it looks like it may be !

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A quick way to change bands, sent to me by Cris

For the Titan II, Black Hawk, AE845, Magnum 257 & 357

Instead of using the func switch and the holding the call button for 3 seconds, program into memory a channel in 11 meters or use LCR. quick and easy.

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Microphone configuration Pin Descriptions

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       1 - Audio
       2 - Receive
       3 - Transmit
       4 - Ground = Channel Down, 22K Ohm to Pin 3 = Channel UP (was originally listed as 2.2K, a visitor told me it was wrong)
       5 - Ground and Switch common
       6 - 13.8 Volts.  SEE CAUTION BELOW

CAUTION: Shorting-out Pin #6 can cause damage to radio!  If you decide to install a new mic,  we strongly suggest you remove pin #6 from the mic plug to avoid any possibility of a short!

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Variable Adjustments

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       RV-1 - S-Meter Signal Strength
       RV-4 - AMC, AM Modulation
       RV-8 - RF Output Meter
       RV-9 - ALC, SSB Modulation and Peak Power.
       RV-14 - FM Carrier Power
       RV-16 - AM Carrier