Problems charging JR Transmitter

[MADCooP]

Wondering if any of you guys might be able to help me find out which is at fault, my charger or my Tx charging curcuits.

I have a JR Tx here which I got second hand. With the supplied batteries, the unit would power up and operate normally. I have now tried charging it, and am able to use the Rx side of the charger okay(verified by illumination of the LED), but when I plug the Tx cable in, it does not appear to be doing anything. Battery is fitted to Tx correctly but no led....

This wall charger should produce 5V on one side(Rx), and 10V on the other(Tx). When tested with a meter, it appears I am getting 6.5V approx on Rx side, and nearly 18V on the Tx side. Is this right?

Basically I am looking for an easy way of telling which would be at fault. Any help appreciated.

[hawkman]

Silly question, may be, but is the charger the correct one? I tried charging my Friends JR radio some time ago, using a fast charger. The socket fitted into the radio ok but it wouldnt charge. I reversed the polarity where the leads plug into the charger, and it charged ok.

He had the supplied charger but we wanted a quick charge, could be that JR has a different setup.

If I am barking up the wrong tree, maybe the LED is broken? I dont know how good they are. have you removed the battery and tried charging it seperate from the radio?

Rob

[Heli Jim]

You are correct in that JR radios and Spektrum radios are different than most other
radios for their charging jack polarity.

You need to make sure that you use the right settings if you are using a different
charger than the manufacturer's

[uneverno]

What is the ouput voltage of the battery? From what you say, the charger is working properly. You may have a dead cell, or there may be an open connection on the battery itself.

JR requires a (+) outside ring and (-) center plug. That's the opposite of most radios. Most chargers have built in protection circuitry which will prevent them from "charging" if the polarity is reversed. This prevents minor inconveniences such as fires and explosions. (What ends up happening is an accelerated discharge - not good if it goes too far - sorta like a nuclear meltdown once it starts...)