I was wondering if anyone could provide some insight into the issue I'm having.

I have a Hobbywing Xerun 120A 1S. When I turn it on it just beeps twice then pauses, then beeps twice then pauses and so on. The green LED flashes as well. I can't even get the set button to work so I can calibrate it. Everything is hooked up correctly. The steering servo works. But the ESC doesn't do anything.

I bought it used off of here from someone pretty well-known. This is the first time I've hooked it up so it has never worked for me.

In doing some searching it seems like this is the result of "abnormal voltage" from the batteries. But I've tried the batteries in a different car and it works fine. I've tried them with storage voltage, fully charged, and discharged. Same thing.

So, anyone know what to try next?

Try this, hope it helps
http://www.falconsekido.com/blogs/news/tagged/software
To Calibrate:

Make sure your sensor cable is connected and it is in good working order (they go bad sometimes)
Make sure your motor's sensor board is not bad (they go bad sometimes as well)

Start with everything off, then follow the steps.

1. Turn the radio on.
2. Make sure that your radio settings are at neutral/default (throttle trim = 0, brake trim = 0, etc.)
3. Connect the ESC to the battery - Do not turn it on yet.
4. While holding the switch button down, turn on the ESC and keep holding the button down until the ESC starts beeping (about 3-5 seconds) - which tells you it's in calibration mode.
5. Once it starts beeping, let go of the button.
6. Leave your throttle at neutral - then hit the button once (you should hear 1 beep).
7. Hold the throttle to Full - then hit the button once (you should hear 2 beeps).
8. Hold the throttle to Full Brake - then hit the button once (you should hear 3 beeps)
9. It should now be calibrated.

If this does not work .. try reversing the throttle signal on your radio and repeat the calibration process.

Troubleshoot log contributed by Joey Krysinski
(Updated Dec 2013)

Yeah. I've tried all that. I actually have another Hobbywing ESC so I'm familiar with them. It won't do anything. If you hold down the set button or don't hold it down it immediately starts beeping.

I know this sounds crazy, but try hooking up a close to dead lipo in it. Maybe around 3.7v. See if you can get into it then. I wonder if it's set to a manual lower voltage and anything over that, trips the high voltage protection? I only had this happen one time with a ipo that was charged to 4.24, faulty charger, should have been 4.20. It was a HW also.

Tried a discharged 1s pack, a fully charged 1s pack, and a 2s pack. Still nothing. Emailed Hobbywing USA and they said it sounds like an issue with the MOSFET board.

Guess this teaches me a lesson about buying used electronics...

Get with the seller. If he doesn't want to do anything, leave appropriate feedback and/ or start a feedback thread for mod intervention.

Did you set throttle to Reverse?, From the manual....

Switch off the ESC, turn on the transmitter, set the direction of throttle channel to
”REV”, set the throttle trim to “0”, set the “EPA/ATV” value of throttle and brake channels
to “100%”, and disable any ABS function on your transmitter.

I've been communicating with the seller. He's suggested many things for me to try. We're still trying to figure out what we can do.

I've never been able to set the ESC at all. It's like the set button doesn't do anything. I hook it up, turn it on, and it immediately starts beeping. If I hold down the set button (which is how you set the neutral, full throttle, brake position) it does the same thing. Tried the throttle in normal and reverse. Same thing.

Try reloading the firmware and resetting everything to factory. I has a 2s do the same thing to me and after I reflashed it with firmware it worked. Also check your cap. Had one that wouldn't program since the cap had leads had cracked and it was getting too much backfeed

I can't reload anything. I can't get anything to connect to it. There is no capacitor on it.

For now I've just bought another ESC and boxed this one up. Guess it's a lesson I had to learn.

Sorry missed the part about it being 1s. Either way you should be able to load it to the USB computer software with the program card and reflash it.

Did you try to clean power switch !!