Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Jenwin
 
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Default Sharp VCR playback distortion

I have Sharp VC-MH704 thats been working fine for the last 4/5 years
through the RF sockets, but never through scart.
It has even been used on 2 different TVs in this way with no problem.

However, now we have just purchased a JVC AV-28E50SK Digital Tv. (Also
purchased a DVD recorder and recently changed it to another model, but
problems occurs with both and without the dvd plugged in).

The problem is.....

The VCR will happily tune and playback the TV through both RF and Scart
sockets, but with either scart or RF plugged in, as well as both
plugged in, the video playback is distorted.

The picture is fine for about 5 seconds then it distorts diagonally
along and goes black and white with sound problems for about 3 seconds
and then is fine again and repeats.

We have tried every type of tv configuration in case of interferance
as well as playing using just the RF to connect as well as just the
Scart, but playback still has the same issue.

Tracking makes no difference.

We thought it may be interference, but no combination seems to help. Is
it a problem with the VCR or with the TV?

As i said the tv will happily use the ariel signal from the vcr to show
the tv channels.

It happens with all pre recorded videos, although we have no tried a
home recorded one, or even tried to record on the vcr.

Any ideas please? This is sending us nuts!!!! Will happily get the VCR
repaired or buy a new one if the problem is with it and not the new TV.


Cheers!!

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Dave D
 
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Default Sharp VCR playback distortion


"Jenwin" wrote in message
ups.com...
I have Sharp VC-MH704 thats been working fine for the last 4/5 years
through the RF sockets, but never through scart.
It has even been used on 2 different TVs in this way with no problem.

However, now we have just purchased a JVC AV-28E50SK Digital Tv. (Also
purchased a DVD recorder and recently changed it to another model, but
problems occurs with both and without the dvd plugged in).

The problem is.....

The VCR will happily tune and playback the TV through both RF and Scart
sockets, but with either scart or RF plugged in, as well as both
plugged in, the video playback is distorted.


That seems to be a contradiction, it plays happily but it distorts? I don't
get it.
The picture is fine for about 5 seconds then it distorts diagonally
along and goes black and white with sound problems for about 3 seconds
and then is fine again and repeats.

We have tried every type of tv configuration in case of interferance
as well as playing using just the RF to connect as well as just the
Scart, but playback still has the same issue.

Tracking makes no difference.

We thought it may be interference, but no combination seems to help. Is
it a problem with the VCR or with the TV?

As i said the tv will happily use the ariel signal from the vcr to show
the tv channels.

It happens with all pre recorded videos, although we have no tried a
home recorded one, or even tried to record on the vcr.

Any ideas please? This is sending us nuts!!!! Will happily get the VCR
repaired or buy a new one if the problem is with it and not the new TV.


Try the VCR on other TVs. If it works fine it may be your new TV has a sync
fault or has been maladjusted at the factory. In layman's terms, VCR sync
isn't quite the same as broadcasted sync, which is why some old TVs required
a special video channel to cope with the difference.

Dave


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Mike Berger
 
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Default Sharp VCR playback distortion

If you record and playback on the same machine, or play a tape
without macrovision copy protection, does the problem disappear?

Jenwin wrote:
I have Sharp VC-MH704 thats been working fine for the last 4/5 years
through the RF sockets, but never through scart.
It has even been used on 2 different TVs in this way with no problem.

However, now we have just purchased a JVC AV-28E50SK Digital Tv. (Also
purchased a DVD recorder and recently changed it to another model, but
problems occurs with both and without the dvd plugged in).

The problem is.....

The VCR will happily tune and playback the TV through both RF and Scart
sockets, but with either scart or RF plugged in, as well as both
plugged in, the video playback is distorted.

The picture is fine for about 5 seconds then it distorts diagonally
along and goes black and white with sound problems for about 3 seconds
and then is fine again and repeats.

  #4   Report Post  
Posted to sci.electronics.repair
n cook
 
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Default Sharp VCR playback distortion

Jenwin wrote in message
ups.com...
I have Sharp VC-MH704 thats been working fine for the last 4/5 years
through the RF sockets, but never through scart.
It has even been used on 2 different TVs in this way with no problem.

However, now we have just purchased a JVC AV-28E50SK Digital Tv. (Also
purchased a DVD recorder and recently changed it to another model, but
problems occurs with both and without the dvd plugged in).

The problem is.....

The VCR will happily tune and playback the TV through both RF and Scart
sockets, but with either scart or RF plugged in, as well as both
plugged in, the video playback is distorted.

The picture is fine for about 5 seconds then it distorts diagonally
along and goes black and white with sound problems for about 3 seconds
and then is fine again and repeats.

We have tried every type of tv configuration in case of interferance
as well as playing using just the RF to connect as well as just the
Scart, but playback still has the same issue.

Tracking makes no difference.

We thought it may be interference, but no combination seems to help. Is
it a problem with the VCR or with the TV?

As i said the tv will happily use the ariel signal from the vcr to show
the tv channels.

It happens with all pre recorded videos, although we have no tried a
home recorded one, or even tried to record on the vcr.

Any ideas please? This is sending us nuts!!!! Will happily get the VCR
repaired or buy a new one if the problem is with it and not the new TV.


Cheers!!


Have you tried changing the output RF modulation frequency on the VCR RF out
and tuning in the TV to match ? Diagonal patterning is often due to beating
of harmonics from the local modulator "transmitter" frequency and some
internal or external freequency

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/



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Dave D
 
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Default Sharp VCR playback distortion


"Jenwin" wrote in message
oups.com...
Um....

By playsback but distorts i mean that it will play th tv through the
vct but a tape distorts.

Im really sorry but i think we have tried this with no luck but it
doesnt really make alot of sense to me! ...

"Have you tried changing the output RF modulation frequency on the VCR
RF out
and tuning in the TV to match ? Diagonal patterning is often due to
beating
of harmonics from the local modulator "transmitter" frequency and some
internal or external freequency"

Anymore advice? Is it not likely to b a vcr problem that can b fixed by
repair? This would be a nice easy solution!

Thanks


Have you tried the VCR on another TV as was suggested? Until you do that,
no-one can answer for certain whether it's the TV or the VCR to blame.

Dave




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Electromotive Guru
 
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Default Sharp VCR playback distortion

Try to hook up the VCR to work through channel 3/4 (switch on the back
for the internal rf-modulator) or 0 ("video", etc.),
depending on your setup. Try this setup (if you haven't already):

Cable-in to VCR RF in ("cable"; "antennae";
etc...)
VCR RF-out to TV ("out to TV")
VCR A/V in from DVD (use digital inputs of VCR to process DVD signal)

The VCR's in-board block-converter will be able to automatically
manage the two different inputs through the tuner. Often digital
input is referred to "channel 0" on the VCR tuner like an
additional channel, depending on model. Consult a manual for your
unit.

Be sure that if you use any one channel to view from the VCR, that the
channel is properly-tuned, and that if setup on channel 3, that both
are set to channel 3 or channel 4 respectively. This sounds like an
Automatic Fine Tuning conflict. An untuned channel will often go into
a seek-mode with most modern tuners, hence the V-sync mismatch,
because it cannot get a proper lock on the signal. The easiest
starting point is to try retuning your VCR tuner to what signal you
have available, then tune the TV to the VCR's signal.

If the above setup did not change matters, double-check that your TV
is set to CATV and not AIR. If your VCR/TV does not have an RF
output, you simply need an RF modulator.

I know exactly the problem you are describing and if I remember
correctly, it is solely with the signal tuning. This is not
indicative of a component problem with either the TV or the VCR. Set
AFT to on for both TV and VCR (where applicable) after tuning each in
the order specified above. Use channel 3 as a default for any input,
use channel 4 if channel 3 doesn't work. Make sure ch3-4 settings
match between all related tuners if such a setting exists (look on
the back of the units near where the RF cable connects for any kind
of switch).

Please post if the above does not work...

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