No image on JVC HM-DH3000U when playing D-theatre?
 

I acquired a JVC HM-DH3000U today. It played VHS tapes smoothly. But when it played D-theatre movie tape, there was no image and sound (maybe black and distorted image sometimes). Even though I tried forwarding or rewinding the tape, as well as cleaning the head, no image or sound showed up.

Is it the problem of the tape or the machine itself?

Check the user manual, D-Theater may not be available via SD outputs or may not play D-theater tapes at all, Are you using HD component?

Edit: You model does not appear to playback D-Theater movies according to this page:
https://www.us.jvc.com/archive/video/digitalvhsvcrs/

I did use the HD component. But it just doesn't play the tape. The screen remains black when playing the tape.

As I said above, your model does not have D-Theater feature, It can only playback D-VHS tapes recorded from an ATSC tuner programs. It can however playback high bitrate D-VHS tapes recorded using D-VHS tool thru firewire and the file has to be prepared in PC using a specific script.

Well, latreche34, I think you should double-check the specs of my HM-DH30000U. The website which you provide says my machine supports "D-Theater compliant with the advanced D-VHS security system".

Can you please give me other useful advice, especially after reading the specs and user manual of my machine?

Which page of the manual talks about D-Theater? I can't find it, But JVC is listing it as 30000 not 3000 maybe that's the difference although I don't think 3000 ever existed.
If your VCR has the D-Theater logo on the front panel it could be an electronic malfunction, possible leaky caps in the power supply that powers up the D-Theater decoding chip.

May I ask which caps in the power supply I should replace?

Maybe I should have them replaced whether they are leaky or not just to be safe.

I don't know, You need a service manual and some test equipment and follow the test procedures. You can still take it a part and look around the power section and check for any leaks or bad smell, Though caps can fail without leaking or smelling.

I managed to capture a few photos of the distorted image when playing a d-theater tape. Can anyone please tell me whether this is the problem of the tape or the circuit board or something else?

AVS forum have a lot of members who own D-VHS decks and threads about this issue.