Check this out:
I have tried each of the JVC DVHS decks on the TWC HD cable system in NYC and the Cablevision HD cable system in CT. In each case, the cable box is the S/A 3250HD, and the connection is via firewire. The results are bizarre.
First, for you JVC HM-DH5U fans, let me point out that as good as the HD picture is via component from all of the decks, the HDMI output exclusive to the HM-DH5U is so superior, it's not funny. I didn't think the HD picture quality from these decks could be improved much, but I was wrong. For you lucky large display owners with HDMI digital inputs, that alone makes the JVC HM-DH5U extremely desirable if you have a collection of pre-recorded DVHS tapes.
Now, the weirdness:
The JVC 30K deck records from all thirteen available HD Cablevsion stations perfectly. The 30K only records HBO and Showtime HD on the TWC NYC system, but it does record, so TWC NYC just needs to set their HD copy flags correctly for NBC, CBS, ABC, Fox, Discovery, PBS, etc.
HD tapes made from these TWC and Cablevsion broadcast sources with the 30K also play perfectly on the 40K and HM-DH5U.
The JVC 40K deck records the TWC NYC stations that the 30K records. But get this: It will not record any of the Cablevision stations even though the 30K will. Similarly, the HM-DH5U will not record any of the Cablevision stations though the 30K will.
Oh, and once upon a time, the 30K when first installed recorded WNBC-HD and WCBS-HD off the TWC system...for a grand total of about 24 hours! Then the ability to record those stations mysteriously disappeared. Indeed, if you even attempt to record them now, the 30K deck locks up completely, and you have to reboot to get it working again.
Those tapes made of NBC/CBS during that initial 24-hour window play perfectly on the 30K deck that they were recorded on. But they serve up a blank screen on the 40K and HM-DH5U, as I mentioned in another thread. Unless, you hit "pause," that is, and then, Voila! You get a perfect HD still image of what had been recorded on NBC and CBS. But hit play again and the picture disappears.
To say this is all beyond strange is beyond an understatement.