The inverter board is the "power supply" inside the case.  The DMTECH Service website opens with a video showing how to replace a couple of capacitors on the board but I would not advise non-technical people to attempt this.
I have the same no picture but sound on a DMTECH but so far I have not opened the case to have look - I have to be in the mood.
Does anyone get answers to these Qs?
                
 John
                
 January 2010