Regulator Circuit for Maxon Radios

Adding Regulator to Maxon  SP2000 &  DM2550 series.

Build up the regulator on a small strip of Vero board. To keep the size down the 0.1uf input capacitor is a monolithic type and the output 10uf capacitor can also be a Tantalum, which will also help to keep the size down. 
The tab of the regulator is connected to the output pin, so will need to insulated above the metal frame of the radio.

To connect the regulator into the Maxon DM2550.

Reading from the left with the BNC connector towards you, locate the track on the sub PCB at the front of the radio, which runs vertically from pin 6 of the interconnector plug to pin 5 of the D9 connector. Cut this track, scrape the green coating off the cut track and solder in the Input and Output wires from the regulator, Input wire at the top, Output wire below. Scrape the green coating off the earth plane next to this area and solder the regulator earth wire.
Mount the regulator at the back of the radio using T220 insulators. Take care to mount low enough to clear the metal shield and syscon PCB.

 

To connect the regulator into the Maxon SP2000 series.
Remove the speaker clamp screw and carefully unclip the front plastic cover. Note - the foam liner will bind the panel in.
Using a counter sunk screw mount the insulated regulator on the recessed section of the front cover, this will kept the regulator clear of future interface circuits that have been added to the syscon PCB.
Remove the Red power wire that was connected to the rear battery connector form the Power PCB and wire in the regulator Output wire. The Input wire to the regulator is wired via the PCB fuse (that is on the battery connector PCB) to Pin 5 of the D connector.