I purchased a used P2V+ and it had two maladies out of the box.  1, the S1 on the remote is broken (new switch inbound, will replace this week), and 2, the range extender doesn't seem to two.
I mention the S1 because I'm curious if there's any possible reason that would affect the functionality of the Range Extender. I've pored over the manual and can't see any possible reason..   I don't believe the S1 is in GPS mode because I can take it out and fly it after I get slow green flashing (I'm 99% sure that's GPS lock, correct?) and it still drifts, so I believe I'm in the other (can't remember the term) mode... no biggie.. I'll get that switch fixed later...  however, I really would like to get the FPV working with my Vision app.

The symptoms..

Can charge. Power light will be yellow until full and then display green.   Pull the cable, turn the power switch on, the Power light goes Red and the System light never illuminates.  That's it.  No amount of waiting will change that symptom.
I've tried the reset pin many times with no change in symptoms.  I've held it for up to 30 seconds. the Power light never flickers, the System light never illuminates.

I assume the radio has taken an impact based on the fact that the S1 toggle is broken, but I don't see any real impact marks or scuffs on the Range Extender...  I've read of plenty of different maladies with them, but none match my symptoms, specifically.

To summarize...
power switch off, plug charging cable in, charges yellow and then turns green.
power switch on, Power light turns red with charging cable unplugged, Power light turns yellow with charging cable plugged in.

This is the case no matter what the power status of the copter or the radio.

Thanks very much for any thoughts/suggestions

Hi . If the aircraft drifts when the rear LEDs flashing green , please try an IMU calibration . And please confirm your device has been binded to the aircraft . Hope this could be helpful : http://forum.dji.com/thread-35181-1-1.html

DJ, is the RC you have the newer model that has the thumb wheel on the bot term left corner and has four led green lights to the right of the power slide switch?  Additionally it take several hours to charge up the wifi extender and you have to bind it to your Phantom. The wifi extender will provide you with telementry and video back to your tablet or phone from the camera. The RC if the newer model also takes several hours to charge so you get 4 LED green lights indication a full charge.
The RC has not function or control of the wifi extender. One is 5.8 ghz and the other is 2.5 and both have different functions.
You can go to DJI and under the model of Phantom you have download the manual. It provide some good info on operations.
Good luck!

Patrick, the drifting is caused by wind. If there's no wind, it hovers fine.  I believe the IMU is calibrated just fine, but thanks for the heads up.  I believe it's drifting because the Radio is not in GPS mode. I can't confirm that until I replace the broken S1.  I only mentioned that just to make absolutely sure there's no correlation between the switch setting and the range extender acting funny.

Roy,  I've got the Version 3 with the lipo battery and shoulder wheel on the radio.
I've charged all devices to full green.  The drone battery charges until the lights go out and it takes no more charge. The radio charges until I get 4 full green bars, and I've charged the range extender until the Power light turns green.   I can't bind it to the craft until I can connect my phone with the vision app. I can't connect my phone to it until I have 2 green lights on the Range extender... conundrum.

Thanks for the advice so far but I don't think we've dialed into the issue yet. I look forward to more suggestions.

Bump... Anyone seen an issue like this?

dj_brady@email. Posted at 2016-1-18 23:34
Patrick, the drifting is caused by wind. If there's no wind, it hovers fine.  I believe the IMU is c ...

Please contact your dealer or support center about that problem .

Brady, when you look at your camera setting and wifi with the extender on the controller on and the Phantom on do you see I'd the phones or tablet a wifi SId that says Phantom xxx?

I'm not sure what you mean when you say, "look at your camera setting and wifi with the extender on".
Where would I be looking for that?

As far as the range extender broadcasting an SSID, no, it's not broadcasting anything in its current state.

DJI-Patrick Posted at 2016-1-19 04:52
Please contact your dealer or support center about that problem .

I'll work on that issue later.  The drone suffered a bad crash from the previous owner and bent one arm, pretty good. I've heated the case and straightened out as well as I can, but I'm sure it's still off by a degree and that's probably causing the drifting.  Once I get the switch replaced on the radio and verify that I have it in GPS mode and if it still drifts, I'm going to order a replacement shell so I know the motors are all in perfect alignment. If it still drifts, then I'll contact support regarding that, thank you very much.
This thread is mostly about trying to diagnose the wonky Range Extender.

I just had an epiphany and thought to use my I.T. tools...  *banging head"

And for some reason, I hit "return"..

Crap.  Posting on my phone is a real pain.  Anyway.  I used WiFi analyzer on my android and powered my hardware on. Turns out, the drone Is silently (hidden ssid) broadcasting a dji ### ssid. Looks line the range extender is just screwy. I'm still curious if there's any way to diagnose it further. . .  Thanks again for the info so far.

Has no one seen these symptoms with their range extender?

In the FWIW category...
I took my Range Extender apart today and discovered one of the micro-soldering points on a little square chip (capacitor, perhaps?) had a bad solder joint. I was able to apply pressure and the range extender would light up green and start working. However, my soldering skills aren't great and I think I cooked the chip trying to heat the area to apply solder and I never got it to light green again, after trying to get solder to the broken connection.   I learned by doing and I have a replacement range extender on the way.
Just wanted to update the thread since I found the culprit.

Thanks for the update, sorry to hear that you had a melt down. I hope you can get the bird up and flying soon.

retired dog Posted at 2016-1-26 07:52
Thanks for the update, sorry to hear that you had a melt down. I hope you can get the bird up and fl ...

Fortunately, flying isn't an issue (aside fro my other thread, regarding the wonky flight, post crash and replacing with generic props, but I discovered a cold solder break in one ESC)...   I just can't fly with FPV (or low batt notifications) until I get the replacement re700 delivered.