What is the battery for - Epiphone SG Prophecy Custom EX Electric Guitar (Refurbished)

what is it< must I google to find out what it is?
ok,,,
did you buy it used and broken,? if yes read the manual first.
The Traynor TVM50 battery powered amplifier is designed for the musician on the move
posted to computers and is not one.
the batteries must be recharged and not connected backwards
if the charger inside, is bad then so will be the batteries dead.
im reading your manual now , and it tells me.
quote
This LED illuminates when the amp is being charged. Once the battery is fully charged, this LED will dim and turn off. The battery requires 24-hours to be recharged properly.
more
2. For best performance, ensure that the TVM50 is switched off while the DC charger is connected. The TVM50's battery charging system is not designed as an AC power source. Operate on battery power only. ,<<< see this?
3. The TVM50's battery is lead-acid based and should never be fully drained. If the TVM50 is in storage it is recommend to recharge the battery at least every 1 or 2 months.
, the manual is free.
here
http://traynoramps.com/guitar/tvm/product/tvm50/

Either the batteries that you put in as new were already on their way out or you have a current drain that is depleting the battery. Use an ammeter to determine when guitar is off if there is any drain on the battery. If so, that is the culprit.

Sure the new battery has power?
Did you put the battery in correct? are all contacts (in the amp and on the battery) clean and shiny?
Check all this, before you press the on button.

It's always possible the new battery had lost it's charge before it was installed. Check it with an ohm meter for it's voltage. Other than that, either the contacts in the battery holder may be in need of cleaning or the battery wasn't installed correctly.

If the new battery tests good on a voltmeter ( you'd be surprised how often they don't) I would suspect that the battery holder's contacts need to be cleaned.

It is easy to replace the battery in your Washburn guitar.

The battery compartment is located where you plug in an instrument cable to your guitar. Simply open it and take out the old battery and put in a new 9V. battery.

Regards

To change the battery in a Kurzweil PC2x, follow these steps:

1. Power off the device and unplug it from any power sources.
2. Remove the screws on the back panel of the device to access the battery compartment.
3. Carefully remove the old battery, taking note of its orientation.
4. Insert the new battery in the same orientation as the old one.
5. Replace the back panel and screws.
6. Power on the device to ensure that the battery change was successful.

It is important to turn off the battery when not in use... they may have a switch OR often when you plug the guitar cable into the unit that completes the circuit to the battery. Another thing the 9 volt batteries are not the greatest. With continuous pwer I would expect the battery to last a couple days. Remember that the devices that have a pushbutton to alternately turn on the device DO still place a small current drain on the battery... For those devices REMOVE the battery when unit is be idle for a week or more.

Take it to a Battery World shop or a similar one that only deals in all types of batteries. They will solve it quickly. Or you could go to any of their websites and ask them the question.
Good Luck

try resoldering the circuit board where the power socket is ... as there is a switch on the socket that disconnects the batterys