chargers are usually low voltage output between 12 - 24 volts dc and have a max load of 1 - 2 amps depending on the unit , your unit should have specs on it somewhere or try to look them up on a company web site if available, if you get the wrong charger you can burn out your tdr.
This is CABL.com posting #171917. Tiny Link: cabl.co/mSS1