diy power supply for mobile rig

Here is a guide to modify your PC power supply unit to power up your mobile rig. If its done correctly you can have a cheap (regulated) VDC power supply solution for your mobile rig to operate at home.
Step I
First get a ATX PC power supply from the nearest computer store. Price is around RM30-70 but better get an expensive one... because the amp is a bit high than the cheaper.

Make sure it could supply sufficient current. Look at the label. We need at least 16amp at 12V for a sufficient operation of mobile rig. Lower Ampere rating means that your mobile rig can't transmit with a typical HIGH setting (50w). i suggest better get 22amp and above.


Step 2

Look for ATX power connector. Look for black and green wire at the ATX connector. The wire position is 4th from the top left side of the connector and 4th from the bottom right side from the connector as pictured above.





Cut the black and green wire. Trim all the other wires as we wont need them.
Tie both Black and Green wire together. Connect both Green and Black wire to bypass the PC Power Supply unit. Insulate it with some tape. and switch on the power supply. If the fan is running, that means you’ve successfully completed this step!







Step 3.
Turn off the power supply. Look for HDD, CDROM power connector, as pictured above. Cut all wire from the connector.

Separate 2 black wires and one yellow wire. Combine both black wires together.

Look for an extra mobile rig power connector, this can be obtained from electronic shops car accessories, or car battery shop.

Connect the yellow wire (+12 volt DC) to the positive terminal at the power connector as pictured above. Connect both black wires together and put it to the negative terminal as picture above too.






Step 4

Cut all unnecessary wires, connector, and leave the power supply with just the rig power connector like this. It will look much more presentable and neatly prepared.

Take 1 red wire and 1 black wire, tied up to resistor. Used 10 watt 5.6 ohm J. it use to stabilized the power when you transmit.

You can test the output voltage of this power supply by testing it with Voltmeter/Multimeter. Here you can see that the power supply output voltage is about 12V, which is sufficient to power a mobile rig (13.8V +/- 15%).

Finally, connect the power supply to your mobile rig to power it up. Enjoy your QSO!

FAQ: Nice, but my mobile rig require 13.8VDC to operate, this PSU only supplies 12V, it won’t work.

 Actually it can work. Mobile rigs requires 13.8 +/- 15% VDC to work (check your rig manual). and that gives a range about 11.7V – 15.8V of stable voltage potential. So a 12V power supply with sufficient current (15A and above) is definitely sufficient to power the mobile rigs.


Good Luck.. have a try...
*** I'm looking for diagram that can change PSU to 13.8v and can tx up to 100w. It can be use more than one at once. Do tell me if you know how...