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Recording D-VHS over previously-recorded S-VHS  

post #1 of 10
Thread Starter 
Ordinarily I record D-VHS on my PV-HD1000s using new Fuji ST-120 S-VHS tapes. This weekend I ran out of virgin tape (my new order from Tape World hasn't arrived yet) so I decided to try recording on Fuji ST-120s that I had previously used for S-VHS recording.

It works fine except for the following irritating problem: on playback the PV-HD1000 seems to get confused if I begin playback at the very beginning of the tape. Judging from the front panel display it seems to recognize it as an S-VHS tape and then it never delivers the bitstream to the STB. The TU-DST51 (or 50) seems to recognize that it's getting D-VHS from the VCR (you get the usual "DVHS 1-1" or "D-VHS 3-1" channel display) but then it's just a black screen.

Only by advancing the tape several seconds in before attempting playback can I get it to behave normally, after which there's no problem.

I've seen this behavior on two different PV-HD1000s and on a TU-DST51 as well as a TU-DST50.

Has anyone else seen this? Is there any suggested workaround (apart from, "don't do that")?

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Ron Gomes
post #2 of 10
See my post in "5000 Receiver". Your problem may be the "overwrite" factor if your HD1000's are demo units.
post #3 of 10
Ron-

I have two SVHS 120's I use for simple time shifting. These tapes have had numerous passes on them and they do not cause any peculiar problems at all.

So far to date, I have had only one problem tape and that was a DFS-420 JVC brand. It simply will not record. Upon close examination, I discovered it was damaged on the first several minutes. The bottom edge, where the control track is recorded, is serrated. After a 5 minute leader it records fine. Simply a bad tape.

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Don Landis
Home Theater Pics at: www.scubatech.com Last updated 3/25/01
post #4 of 10
Thread Starter 
Just to clarify: most of my D-VHS recording is on S-VHS tapes and is trouble-free, whether the tape is new or not. The tapes on which I'm having the problem are different only in that the previous recording being overwritten is an S-VHS recording (made on a separate S-VHS VCR) rather than a D-VHS recording.

All my units are consumer units (at least according to the serial numbers posted on the Forum that identify the "demo" units). And I've seen the problem on more than one tape and more than one VCR.

It's as though the new recording starts slightly after the start of the tape, and on playback the VCR sees the S-VHS recording and gets "stuck" in the wrong mode.

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Ron Gomes
post #5 of 10
I have been cannibalizing my old S-VHS library for DVHS and not run across the problem Ron describes.

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"Better living thru modern, expensive electronics devices"
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post #6 of 10
Ron,
I've had the same experience a few times, although it's been awhile since I recorded on prerecorded tapes. My guess is that your SVHS recorder layed down SVHS stuff very close to the leader. You didn't say exactly what your DVHS recording process was, but if the recording process was in hiccup mode while the Dish 5000 was channel setting, I could see a fair strip of tape with nothing on it. That would let the initial "SVHS" impression take hold.

I've also experienced the very strange situation where the PSIP info seems to have made it to the tape but the image didn't. The result is that during playback the STB reports "DVHS 3-1" but there's nothin there. This all happened during the early stages of my hub experiments. The channel info is part of the isochronous stream, so how this can happen is a mystery to me.

To fix the tapes you might try patching a few seconds of DVHS as close to the start as possible, perhaps using record/pause to help sync things up sooner.

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- gridleak...
Analog -- Always out of adjustment.
Digital -- Always one more bug.
post #7 of 10
You might also try bulk erasing the tapes and then, if necessary, record a short HiDef section at the beginning.
post #8 of 10
Bulk erasure, as Orio suggested is what I do as a rule here when reusing a tape. This is a very quick process that will clean all the recording off the tape, including the control track.

What your problem sounds like is a control track that starts right after the leader and this triggers the machine to that analog mode and then the new control track starts and the DVHS must now switch into that mode. This takes time. While the DVHS should replace the control track, it may not do it effectively considering head alignments etc.
Bulk erasure is the answer. Try it and let us know.

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Don Landis
Home Theater Pics at: www.scubatech.com Last updated 3/25/01
post #9 of 10
Having just bought but not yet recieved my PV-HD1000 please excuse my ignorance in asking-

1. are S-VHS tapes equal to D-VHS tapes for HD recording on a PV-HD1000 or are they just good enough for time shifting but not for archiving a movie

2. will S-VHS tapes cause any harm to the PV-HD1000 heads or other mechanisms

3. in using S-VHS tapes do you have to make any modifications to the shell for the PV-HD1000 to accept them as D-VHS

Murray Kerdman
post #10 of 10
Quote:
Originally posted by mkerdman:
1. are S-VHS tapes equal to D-VHS tapes for HD recording on a PV-HD1000 or are they just good enough for time shifting but not for archiving a movie
Murray, you're going to get a wide variety of opinions on this. DVHS tapes are slightly better than SVHS tapes. They have higher remanence, better lubricity, and are smoother. They are also more expensive. Whether you need them or not depends on the condition of your machines. My machines have new heads, and are in perfect working order. I've gone through hundreds of new TDK ST-120XPSP $4.76 tapes without a single lost pixel. Those recordings will be readable on most, if not all working HD1000's. If I used more expensive DVHS tape (JVC DF-300 or DF-420) there might be a couple more very worn out HD1000's that could read the recordings, but to me it's not worth paying twice as much for tape to ensure my recordings will play on every machine out there.

Anyway, if I make a copy for someone who has a worn machine, I can always use the type of tape that works best for them.

To finally answer your question -- If your machine is in good condition, use DVHS or pro tape for time shifting, and plain SVHS for archiving.


Quote:
2. will S-VHS tapes cause any harm to the PV-HD1000 heads or other mechanisms
If you have very worn heads new SVHS tapes will tend to clog them, and a good DVHS tape with a few passes on it will tend to clean the heads! If your heads aren't worn, it makes no difference. I don't know of any studies done on comparing head wear caused by DVHS vs. SVHS tape. My guess is that pro tapes with lubricated coatings, e.g. TDK CMPro, will cause less wear.

Quote:
3. in using S-VHS tapes do you have to make any modifications to the shell for the PV-HD1000 to accept them as D-VHS
No, the HD1000 doesn't care. The DH30000 is the one that cares and will always try to record analog when stuffed with an unmodified SVHS tape.

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-Roger
Analog -- Always out of adjustment.
Digital -- Always one more bug

[This message has been edited by gridleak (edited 08-01-2001).]
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