My new but very flakey shaw dcx3510-M 500GB HDVR will play back anything we record, it will show the guide, but when we select a channel for "live" TV the screen is blank. It shows the guide banner on the bottom if we change channels, but where the TV image is supposed to be it is just black.
Hooked to brand new LG TV, via HDMI. Sometimes it works (rare) and oddly it seems to work more often (though still rare) on higher channels at least above 60...or so...
For giggles I tried a few HDMI cables, and different TV inputs...but it just plays all the recording we have...and no TV.