The RS910 power supply is used, together with the RS9044 transceiver, in the dutch ATF2 car phone network. Trough Museum Jan Corver those transceivers and the power supplies have found their way to many shacks of Dutch HAM's.
The power supplies can handle 24 Volts at 19 amps.
Joost Vossen, PE1JVS, has found an easy way to convert these power supplies to 12 volt. His instruction you can find here

Click on pictures for large version

In this document there is a regulator board, where the most of the modification takes place. This board is pointed out on the first picture above.
On the backside there are two terminals, through which the RS9044 were fed. These terminals must be removed, and your left with 2 holes which are too big for the new terminals. Just replace the aluminum plate with a new one with the right size of holes for the new terminals. Be sure the terminals are insulated from the plate. Picture 2 and 3 show this plate AND the new terminals. Also on this plate the 230 terminal with net filter is mounted. On picture 3 there is also the big blender condenser over the net filter visible.

The exit current is fused with 8 glass fuses of 4 amps each. On the regulator board you can find 2 big orange plugs with the positive (colored wires) and negative (black wires) power leads. Those wires must be connected to the exit terminals on the backside. I have soldered all the colored wires and the black wires together, so i can connect the terminals with a single 6 mm2 (no 4 SWG) wire each.

Testimonials in the use of the power supply

The behavior of the power supply is stable. In the years that i use this power supply i have met no problems. I have tested the power supply by connecting it with 6 car light bulbs of 55 watt each. Those were lit for half an hour with no problems. The consequence of this exercise was that it became quite warm in the shack and i had to wear sun glasses, but the power supply kept working.
In combination with the FT897 this power supply is working well. There is no interference to be heard on the HF bands from the power power supply. I have made a comparison with a big car battery and there is no difference to be heard.