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.

Make sure it could supply sufficient current. Look at the label. We need at least 10-17amp at 12V for a sufficient operation of mobile rig. Lower Ampere rating means that your mobile rig cant transmit with a typical HiGH setting (50w).

Step 2

Look for ATX power connector. It should look like this.

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.

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 suffiecient to power a mobile rig (13.8V +/- 15%).

Step 5

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.

Acknowledgments
This howto has been translated directly from Malay version original article published in Forum Anak Perlis written by me.

You can refer there for a complete malay version of the guide if you find the English version is confusing.

Tags: amateur radio, diy, Ham Radio, hamradio, Hobbies, hobby