you say you can hear the radio key on another radio.
that means it is keying, but very weakly.
no modulation?
might not be enough power for it if the final is blown, or really weak.
you might see a slight movement on the SWR meter's needle if you set it to the CAL position, turn the knob all the way to the right, and key the radio.
definitely try another mic, and try wiggling the mic cord and connector around while talking into the mic, looking for movement on your SWR meter. (still set to CAL, unless it also reads watts)
im gonna guess that its a blown final transistor, but since this is such a new looking radio (never played with one), im also guessing that its part, if not all SMT, which means unless you have the right tools, and knowhow, you really cant fix it yourself like with the old radios.
might just have to send it to a tech.
good luck,
LC