Rear Projection has perfect picture but no sound.

unplug the tv for about 5 minutes then plug it back in

look for EP98, Q655 and D756.

YOU NEED TO REPLACE THE CONVERGENCE OUTPUT I.C.

It sounds like aging electrolytic capacitors have reduced the high voltage on the "guns" in your projection TV. You cannot fix this problem yourself. There are DANGEROUS high voltages inside the set, even after it has been off for WEEKS. We're talking HEART ATTACK voltages. Call a qualified service technician.

The capacitorson the FMT board have failed, which will cause that symptom. Is the menu screen clear when you hit menu?

Not exactly familiar with this model but sounds like the projector lamp is burned out. Hopefully it's a replaceable type. Try calling these people - http://www.purelandsupply.com

sounds like your color guns are out of alignment and need adjusting. its a cheap fix with a tv tech but i wouldnt recommend doing it yourself. plus, a visit from a tech can tell you if there is anything else wrong/about to b wrong

Go into the menu and set contrast to full, bring brightness up to an appropriate level after.

Sounds like it could be a flyback problem. Are the ends of the picture tubes lit? Do you have audio and or onscreen menues?

If you still can see the DirecTV guide and menu, the problem could be on your satellite receiver and not the TV. Unplug your receiver and plug it back.
If the rebooting did not work, I would suggest to swap the satellites receivers and see if it works.
Good Luck.