sparkles/dropouts with mitsubishi s-vhs deck
Will Sanborn
I have a mitsubishi HS-U770 S-VHS editing VCR which I bought a few months ago.
When I first got it I did some simple editing tests and it worked great.
However, just recently I've started doing some serious editing on it and have
noticed a weird phenomena:
After editing for awhile, using the jog/shuttle control a lot to position the
tape, I noticed some write speckles on the screen. I originally thought they
were drop-outs, but they aren't consistent, they move around on the tape and
if the tape is taken out of the machine, as the manual suggests to clean the
heads with a dirty tape, it did get better. I tried another tape and got the
same results.
As I said, taking the tape out does make the sparkles go away, for the most
part. There was still a 30-second to one-minute section at the beginning of
the tape that was showing the sparkles, but the rest of the tape cleaned up.
A friend thought it could be something like static charge building up on the
playback heads from moving the tape forward and backward so much during
editing, and as most of the sparkles go away, I think it could be something
like this.
Has anyone else seen a similar pheneoma on this or other editing decks and if
so what are yor suggestions, will the sparkles just go away from the playback
if the unit/tape is allowed to rest?
--
Will A. Sanborn, wa...@shore.net
http://www.shore.net/~was1
(my creative writing: sci-fi, fantasy, furry, romance, speculative fiction)
doug beames
Will Sanborn wrote:
>
> After editing for awhile, using the jog/shuttle control a lot to position the
> tape, I noticed some write speckles on the screen.
>
>
I have a Mitsubishi 760 deck (almost identical to the 770) and have
noticed a similar problem, but only in SVHS, and only at EP speed. It
did not occur until I had the deck for a while, and I thought initially
it was related to temperature, but now I am not sure, as it does not
happen in regular VHS mode at EP speed or in either mode at SP speed.
Can you confirm this in your case?
- Doug
Will Sanborn
doug beames <doug_...@mindlink.bc.ca> writes:
For me it's happening in both S-VHS and VHS, SP modes, haven't checked out EP
modes yet. It's a fairly new deck (three months old) and the sparkles come and
go. I'm also seeing some glitches here and there when I do editing, so I'm
thinking of taking the machine in to get it looked at, might as well take
advantage of the extended warranty.
Has anyone else noticed any behavior like this with a mistubishi deck?
Laurie Stewart
doug beames wrote:
>
> Will Sanborn wrote:
> >
> > After editing for awhile, using the jog/shuttle control a lot to position the
> > tape, I noticed some write speckles on the screen.
> >
> > Has anyone else seen a similar pheneoma on this or other editing decks?
> >
>
> I have a Mitsubishi 760 deck (almost identical to the 770) and have
> noticed a similar problem, but only in SVHS, and only at EP speed. It
> did not occur until I had the deck for a while, and I thought initially
> it was related to temperature, but now I am not sure, as it does not
> happen in regular VHS mode at EP speed or in either mode at SP speed.
> Can you confirm this in your case?
>
I bought three Panasonic AG7700 machines & have been plagued with
glitches & sparkles. They seem to come from the machines being used with
an Editor which uses the the jog shuttle to find its way to the in
points. Your article seems to confirms that the jog shuttle or something
associated has an effect on the tape. I noticed that if I re edited a
passage on the same poriton of the tape that additional sparkles
occured. The sparkles seem to appear both on the jog shuttled camera
master & the final edited tape.
I also tried VHS & found that the problem did not occur. I also had the
heads changed on one machine but this did not make any significant
difference.
I now have gone over to digital editing & noticed that except very
occasionally the sparkles have disappeared......? the jog shuttle is not
used?.
One thing which does help is to use a more robust tape. Using a
FugiH471S double coated tape results are much better.
I recently finished a six minute film (digital)without any glitches or
"sparkles". Much nicer name "sparkles" is`nt it.
Laurie Stewart.
Will Sanborn
Laurie Stewart <tec...@itl.net> writes:
>> Will Sanborn wrote:
>>>
>>>After editing for awhile, using the jog/shuttle control a lot to position the
>>>tape, I noticed some write speckles on the screen.
>>>
>>>Has anyone else seen a similar pheneoma on this or other editing decks?
>>
>> I have a Mitsubishi 760 deck (almost identical to the 770) and have
>> noticed a similar problem, but only in SVHS, and only at EP speed. It
>> did not occur until I had the deck for a while, and I thought initially
>> it was related to temperature, but now I am not sure, as it does not
>> happen in regular VHS mode at EP speed or in either mode at SP speed.
>> Can you confirm this in your case?
>>
>I bought three Panasonic AG7700 machines & have been plagued with
>glitches & sparkles. They seem to come from the machines being used with
>an Editor which uses the the jog shuttle to find its way to the in
>points. Your article seems to confirms that the jog shuttle or something
>associated has an effect on the tape. I noticed that if I re edited a
>passage on the same poriton of the tape that additional sparkles
>occured. The sparkles seem to appear both on the jog shuttled camera
>master & the final edited tape.
>
>I also tried VHS & found that the problem did not occur. I also had the
>heads changed on one machine but this did not make any significant
>difference.
>
>I now have gone over to digital editing & noticed that except very
>occasionally the sparkles have disappeared......? the jog shuttle is not
>used?.
>
>One thing which does help is to use a more robust tape. Using a
>FugiH471S double coated tape results are much better.
>I recently finished a six minute film (digital)without any glitches or
>"sparkles". Much nicer name "sparkles" is`nt it.
Odd. We thought that it might be related to using the jog/shuttle dial, as the
sparkles become more noticable after using the dial a lot. I've edited stuff on
a VHS deck with jog/shuttle dial before, and this didn't occur, but on my S-VHS
deck, even in VHS mode, this happens.
I can't afford a digital-editing setup right now, so I'll have to get by using
the jog/shuttle dial. When you had sparkles on your tapes, did they eventually
go away? On my tape, they seem to go away after awhile after the jog/shuttle
dial isn't used, so maybe it is related to a static charge or something. I'm
just a little nervous about a few lingering sparkles, but there may not be
anything we can do about that.
Once, again, anyone else see this problem with VHS/S-VHS VCRs, is there anyone
out there with some technical knowledge of the systems who could give me some
pointers?
Thanks.
Laurie Stewart
Will
A little puzzled here dropouts, glitches, & sparkles I assumed they were
all the same thing.
Whatever they are they do not go away on my system. They are present on
the tape. I have jog shuttled to a glitch or sparkle & it is on the
tape.
As you have found I have used VHS on the same machines & I do not get
any glitches at all. I have also noticed that on the domestic machine
the glitches, unless very prominent, do not show up. I have been told
that that is because there are filters which scramble the picture which
obscures the glitches etc.
A friend has a similar set up to me but views his work on an inferior
monitor which seems to obscure the glitches, perhaps on the cheaper
monitors they do the same thing filter & scramble.
I do know that the Panasonic Engineers in the UK did not have an answer.
By the way the glitches were coming at approx 6 per minute, very
depressing after buying expensive equipment. I also wondered about
static & diconnected everything that I could to experiment, I even
bought special power plugs to avoid sound interference, I wasted my
money.
If you discover the problem if you would please let me know.
Thanks
Laurie Stewart
Will Sanborn
Laurie Stewart <tec...@itl.net> writes:
Will A. Sanborn <wa...@shore.net> wrote:
>>Odd. We thought that it might be related to using the jog/shuttle dial, as the
>>sparkles become more noticable after using the dial a lot.I've edited stuff on
>>a VHS deck with jog/shuttle dial before, and this didn't occur,but on my S-VHS
>>deck, even in VHS mode, this happens.
>>
>>I can't afford a digital-editing setup right now,so I'll have to get by using
>>the jog/shuttle dial. When you had sparkles on your tapes, did they eventually
>>go away? On my tape, they seem to go away after awhile after the jog/shuttle
>>dial isn't used, so maybe it is related to a static charge or something. I'm
>>just a little nervous about a few lingering sparkles, but there may not be
>>anything we can do about that.
>
>Will
>
>A little puzzled here dropouts, glitches, & sparkles I assumed they were
>all the same thing.
>
>Whatever they are they do not go away on my system. They are present on
>the tape. I have jog shuttled to a glitch or sparkle & it is on the
>tape.
>
>As you have found I have used VHS on the same machines & I do not get
>any glitches at all. I have also noticed that on the domestic machine
>the glitches, unless very prominent, do not show up. I have been told
>that that is because there are filters which scramble the picture which
>obscures the glitches etc.
>
>A friend has a similar set up to me but views his work on an inferior
>monitor which seems to obscure the glitches, perhaps on the cheaper
>monitors they do the same thing filter & scramble.
>
>I do know that the Panasonic Engineers in the UK did not have an answer.
No, glitches, dropouts and the "sparkles" I'm seeing are all different things:
Dropouts are dropouts on the source tape, caused by an imperfection in the
tape. We see a few of those since we're going from hi-8 source tape which is
more susceptable to dropous than larger-format tape mediums.
Glitches occur for us only at edit points and are occuring frequently enough
to bother me. They occur about once every 5 or 10 edits. Usually we can go
back and re-do the edit and after a couple of tries get it to work. Also last
night I found out if I lay down a good video signal, such as black video
generated from the camcorder with the lens cap on (not all that elegant, but
it works), it makes the glitch problem get better, maybe not go totally away
but it helped us eliminate a glitch that was occuring in the same place after
five or six tries at it. I'm wondering if this could be a problem with the
flying-erase heads, as I thought the system was supposed to give perfect,
glitch-free editing. I've used a VHS edit system before and have only gotten
one or glitches, not anywhere as many as with this system.
And the final problem is the sparkles. These are not physically on the tape,
but appear to be a phenomenon during playback. I know they're not on the tape
because I can't see them during a search at slow speeds. Also, they are not
consistent, like dropouts or glitches, they move around on the screen and they
can get better or worse as we watch the same scene over and over again. The
severity of the amount of sparkles on the screen seems to be tied to how much
weire using the jog/shuttle dial, which once again makes me think of static
buildup or a circuit that isn't shielded or grounded properly.
I need to try and get ahold of customer tech support at Mitsubishi and see if
they know anything about the glitches and sparkles problems. Once again, anyone
else seeing similar problems on a S-VHS/VHS edit deck, please let me know. I'm
starting to get really dissapointed here, after paying so much money for a
system that doesn't live up to my expectations.
TGE
Will,
I have the same exact problem you're describing. I own a Mits 770 and
during the first 3 months, I had clear, perfect looking video in SVHS mode
for both SP an EP speeds. Then one day after about 3 months of use, I
played back something I recorded (off TV), SVHS EP speed and the picture
had all these white sparkels/static (just like you describe). At first I
thought the heads were dirty, so I cleaned them and the sparkels still
remained. The SVHS SP, and VHS SP and EP modes have never giving me any
sparkels, although my SVHS SP speed picture doesn't look as good as it
used to before my machine got infected with this sparkel problem.
Being very unhappy at this point, I returned the machine and got another
Mits 770. It worked fine (SHVS EP speed)... then after about 3 months
use, that damn sparkel problem came back (on a different machine!). I got
so upset, but I haven't taken any action with Mitsubishi to get this
corrected (because I need the VCR to record some shows; maybe when the
season is over in May). I still have 6 months left on my warranty. As
you know, this machine costs a pretty penny and yet I can't even use it to
record SVHS EP speed (which is why I bought it in the first place).
My bottom line: I'm ready to raise hell with Mitsubishi and/or the dealer
I bought this VCR from. I really love the features of this machine, but
what good it it if I can't get a clear picture? I either want this
machine fix or I want my money back so that I can buy a Panasonic AG1980.
If you or anyone else knows how we can get this problem resolved, please
email me.
Thanks, TGE
John Croteau
It's possible that what you are seeing is motor noise. At the top or
bottom of the head drum assembly there is usually a motor static
discharge spring contact. Make sure that this makes good contact and is
lubricated. If the problem disappears during pause suspect the capstan
motor. Also make sure all the shields are on correctly with screws all
grounding screws reinstalled and tight.
John Croteau
Kurt Toolsie
>I have a Mitsubishi 760 deck (almost identical to the 770) and have
>noticed a similar problem, but only in SVHS, and only at EP speed. It
>did not occur until I had the deck for a while, and I thought initially
>it was related to temperature, but now I am not sure, as it does not
>happen in regular VHS mode at EP speed or in either mode at SP speed.
>Can you confirm this in your case?
>
>- Doug
Doug, I too have the Mits 760, and after owning it a for four or so
weeks it also started displaying speckles during playback.
This problem was only manifest at EP speeds, and not at SP speed,
so I suspect it was the same problem as you are describing. I did
not attempt to tape in regular VHS, so I cannot say if the problem
was evident in this mode. Anyhows, I took the VCR back to the store
from which I had purchased it and they sent it in for repair. It came
back a week later and the problem was cured. No reappearance since then,
although I must admit that I hardly ever use my VCR.
Kurt
---
=================================================================
WEBPA
>It's possible that what you are seeing is motor noise. At the top or
>bottom of the head drum assembly there is usually a motor static
>discharge spring contact. Make sure that this makes good contact and is
>lubricated. If the problem disappears during pause suspect the capstan
>motor. Also make sure all the shields are on correctly with screws all
>grounding screws reinstalled and tight.
> John Croteau
No. Not capstan motor noise. Not loading motor noise. Not loose shields.
None of these noise sources is synchronous (more or less) with the
picture scan lines. And the "sparkles" or "comets" are. When they are
present, they repeat at more or less the same place in the picture over
several fields. They are definitiely related to something happening on
the video headwheel. Static brushes (inadequate design) are the problem
on JVCs. There is a service bulletin (maybe two) concerning this on
4900/6900 (and maybe other) model series.
Paul Weber
Albuquerque, NM
we...@aol.com
webpa
doug beames
Kurt Toolsie wrote:
>
> Anyhows, I took the VCR back to the store
> from which I had purchased it and they sent it in for repair. It came
> back a week later and the problem was cured.
Did the shop indicate what it did to correct the problem? I'm always
suspicious when they report the problem "solved" but don't indicate what
they did. Often, I suspect, they haven't done anything substantial.
- Doug
Joe Inoue
I reconstructed my demagnetizer (that was for audio tape deck) to be used on
my U770. Anybody tried this before? I cannot say that it's definite, but I
don't see sparkles anymore on my vcr.