Doug's GPS Page

Please send comments or suggestions to n0jan@qsl.net

Here's how I made a power cord for my Garmin GPS 12. I started out with a cellphone power cord. I've seen these cords at Walmart for as little as 50¢ each. There are several different styles, but the ones I have taken apart all contain a fuse, an LED, a filter circuit, and a 34063 voltage regulator chip, all inside a nice compact lighter plug. The output voltage is regulated to 7.8 volts on all the ones that I have tested so all I had to do was remove the cellphone connector and replace it with one of Larry's Pplugs. Be sure you check the voltage because exceeding 8 volts could damage your GPS 12.

I also made a power cord for my Garmin eTrex. Snap the lighter plug apart and remove the circuit board. By removing resistor R3 and replacing it with a 1.8K ohm resistor (brown, grey, red), I obtained an output voltage of 3.15 volts. Be sure you check the voltage and don't exceed 3.3 volts. Remove the cellphone connector and replace it with one of Larry's ePlugs. I have made several eTrex power cords this way and they all work great.

Take a look at the Hacking eTrex page. He has lots of good stuff about the eTrex and a great MC34063A design aid page to help you get the proper voltage. Wish I had found his page before I spent all the time figuring it out on my own.

If you haven't been to Larry's page yet, you need to go there. He sounds like a heck of a nice guy and he makes some great connectors for the Garmin GPS. Once you read about how his connectors are made and how they are distributed, you'll want to go buy a Garmin just so you can try his connectors.

Garmin GPS Connectors & Cables
Garmin
ON Semiconductor Data
NTE Products Cross Reference
Resistor Color Codes
USFS GPS PAGE
N0JAN's Ham Radio Links

Counter