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Canon XL1S / XL1 Watchdog
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Old January 16th, 2003, 08:02 PM   #1
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Bad playback of non-XL1s recorded tape.

I've been reading up in the forum on the general problems with record/playback on different brands of decks/cameras, and use of various brands of tapes, but nothing quite makes sense for my problem:

I have a 6-month old XL1s used lightly for recording exclusively as a camera. I playback on my (now aging) JVC SR-VS10U deck, which has worked wonderfully for going on 3 years. Over time I've used a variety of stocks, but mostly Sony Premium and Panasonic ME (the PQ and more recently the MQ).

I recently found that playback on the XL1s of ANYTHING recorded on the JVC deck exhibits mosaic-like digital artifacts. I never had cause to playback using the XL1s before.

Ordinarily I would chalk it up to dirty heads on my JVC deck and run a cleaner, BUT the XL1s stumbles even on a tape recorded when the deck was brand new, before mixed stock and general wear should have had a chance to come into play.

I've run a head cleaner on the XL1s with no effect.

My workaround is to re-dub the material from the JVC deck to the XL1s over FireWire. The Cannon will play a tape that it recorded itself just fine.

I've had no playback problems on the JVC deck EVER, so I tend to doubt a problem with the heads there (why wouldn't it show up on playback?), although I haven't extensively tested the recorded tapes on 3rd targets.

Any thoughts from those with more experience than I?

Thanks much, in advance.
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Old January 16th, 2003, 08:24 PM   #2
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The XL1 needs a tape path alignment (best guess). Tape path alignment is very loosely akin to a front end alignment on your car. The tape path is adjusted (various post, etc. that guide the tape out of the cassette, around the upper drum assembly, back in to cassette) so that the tape aligns properly with the video heads on the upper drum assembly. When the tape no longer moves in the correct position across the heads, video playback is impaired. There may be other mechanical or electrical problems that need adjustment or repair, but your symptoms are most similar to faulty tape path alignment. Canon service can fix you right up. You may want to search for tape path alignment for more information.

Jeff
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Old January 17th, 2003, 05:50 AM   #3
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Do I correctly understand that you use the XL1s as a camera only and fire wire to the JVC upon which you do the actual recording? But you sometimes play back on the XL1s? And that you have not tried this before.

I presume you are recording at SP speed. LP speed is likely to have the sort of problem you describe.

It does sound like the XL1s and JVC are not in alignment agreement. Which is not aligned is not clear without additional information (e.g., the JVC could have been off out of the box). You could make some checks against a third machine with tapes recorded by all three machines.

Does the JVC play tapes recorded on the XL1s now and when it was new? If these both play OK, it may be that the playbck amps in the XL1s have gain set too low. There are a numbr of scenarios that could produce these results.

If you send the XL1s to Canon in for adjustment, be sure to include a sample of the tape that does not play properly on the XL1s but does on the JVC, with a full explaination.
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Old January 17th, 2003, 08:50 PM   #4
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Like Don says I assume you recorded in SP and LP mode. All bets are off in LP mode.

It could easily be a problem with alignment with either unit.
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Old January 17th, 2003, 09:04 PM   #5
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Does the JVC play back both old and new tapes that it has recorded? If so, it probably is not out of alignment. Check if the XL1S can playback one of the first tapes it recorded. Post back your results please.

Jeff
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Old January 20th, 2003, 08:51 PM   #6
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Yes to Jeff -- The JVC plays back both old and new tapes that it has recorded.

I have always only recorded in SP mode (the default on both the deck and the camera), and never in LP.

To clarify, when I say I use the XL1s as a camera only, I mean that I record to it, but just never playback on it (until recently). I take the tape it recorded and play it in the JVC deck for capture to the NLE via FireWire.

I have had the deck for 2+ years and the XL1s for only about 6 months. Like I said, the XL1s plays back anything that it recorded itself, just not tapes recorded on the JVC deck. I agree more tests with a third source are warranted.

The JVC plays back BOTH tapes it recorded and tapes recorded by the XL1s, so if the two are out of alignment, the problem only materializes going one-way.

Don, can you (or someone) talk more about this gain on the playback amps? I'm not familiar with that aspect of the technology. Can that cause mosaic-like digital artifacts in the image?
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Old January 21st, 2003, 04:03 AM   #7
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If I remember correctly there was a thread on this board a long
time ago with a similiar problem. The Canon made the same bad
picture when a DV tape from another camcorder was inserted.
I think they all concluded back then that the XL1(s) just works
best with its own recordings and not others.... but ofcourse I
might have this information wrong, not sure...
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Old January 21st, 2003, 05:16 AM   #8
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If the playback head amps and ther asociated analog circuits are not properly adjusted and equalized (frequency response) it can result in errors in the digital output, whihc causes the moasic pattern. Are the errors more to one edge of the image than the other edge or are then evenly distributed over the whole frame?
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