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Old July 11th, 2003, 03:26 PM   #1
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Help, Large blocky artefacts on tapes

Help, I have a low end Canon MV10 DV cam, and a few weeks after returning from hols, while playing back the tape there was a grey vertical band on the left hand of the screen, approx 1 sixth of the width of the screen, with small blocky artefacts on the edge of the grey band (as if the playback could not decode properly, like it was showing blocks of previous frames, each block being approx 20-pixels square). AND NO SOUND. I tested some other tapes that I had in my bag, and they all seem to be aflicted with the blocky corrupt thing and no sound.

I initially thought it could be dirty heads. So not having a head cleaner to hand, I went to work on the head with my trusty isopropyl alc, and cotton wool bud (I know, I know, I should have used a lint free cloth but I'm an impatient lil thing). This actually improved things and got rid of the grey vertical area, however, there were still lots of these blocky artefacts (as discribed above)covering random areas of usually 1 quarter of the screen. More cleaning took place (still using the buds and isopropyl) and the blocks reduced but did not disappear.

I then purchased a cleaning tape and tried it once, twice, and thrice. A little better, but still blocks appearing (blocks of previous frames).

I checked with Canon and its 210 to fix it, one price will fix all. The WEIRD thing is, I just tried to record some new footage, on a corrupt/blocky tape, on the same camera, and the recerding played back fine on the same camera, but with no sound??!?!?!

I'm soooo confused. I'm going to try and get hold of another camera to test the tapes on, but in the mean time, does anyone have any ideas (apart from buying a new camera)?

Million thanks in advance,

Ben
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Old July 11th, 2003, 06:55 PM   #2
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I'm confused by the sequence of things and the current record and playback. If you take a brand new tape (never recorded on) and record video and audio on it, then rewind and playback, what do you get? If you playback the same tape on another camera (go to electronics store and play it) what do you get?
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Old July 12th, 2003, 03:35 AM   #3
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I'm confused myself!! With a new fresh tape, I can record and playback, only problem is NO SOUND. The mic works, as I can test it through an AV feed to a monitor with speakers, it just isnt recording. I plan to get my hands on another camera tomorrow and do some more tests.

Can tapes get "corrupted" by physical damage (a knock, humidity, dirt) or Xray machines (ie at airports) ?

More tests have shown that the playback artefacts are not consistant. Some times I get "shadow blocks" of previous frames that can stay on screen for a few seconds (2 to 8 seconds) in large areas (half the screen), and sometimes tha blocks are small and only cover a small percentage (10% of screen). :( very confusing...
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Old July 12th, 2003, 05:10 AM   #4
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This thread from just several days ago may answer many of your question. Post back with any unanswered questions after reading the thread. I think continued use of the old tapes are depositing material on your heads. Audio is record by heads also. The audio heads are probably clogged and not recording sound (quite possibly the result of your choice of cleaning materials). I would try cleaning the heads, following the directions of a cleaning tape. Do Not Exceed the instructions with the cleaning tape. Improper use of cleaning tapes can damage the heads beyond repair. Depending on the camera, head replacement can be hundreds of dollars.
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Old July 13th, 2003, 04:48 PM   #5
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I'd try to pin down the problem. Are you tapes damaged, or is it just your camera? (and which parts of it: playback or record)

Do follow the instructions on the cleaning tape to a T, and don't use it too much. I think the tape will say 5 times. If it doesn't work then your camera may need repair.
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Old August 10th, 2003, 04:13 AM   #6
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Problem found and fixed.

As I said, cam can record and playback, but with no sound. Old tapes were a mess (loads of artefacts), cleaning did no good.

Sent it off to Canon Imageing Centre (the main repair place) after phoning them and finding that for my model (a MV10, 4 years old) there 1 price to fix anything (180). So I sent it off and it was returned in 1 week, all fixed. Seems the problem was "misalligned heads". Makes sense, the cam could have taken a slight knock. Anyway, all is fixed now. Thanks to Glenn and Jeff for your input.
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