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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.

Zenith Sentry TV/Monitor



 
 
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  #1  
Old March 8th 09, 12:18 AM posted to sci.electronics.repair
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Posts: 24
Default Zenith Sentry TV/Monitor

Hello, all. I have a circa 1991 Zenith Sentry 2 TV model SJ206585 that
still has a great picture but there are diagonal lines (not retrace
lines) that are present in the picture regardless of channel. They look
like the pattern one used to see on old sets when the horizontal sweep
wasn't locked but in this case they are superimposed on what would
otherwise be a perfect picture. Does anyone know what might be the
cause? Thanks for your time and comment. Sincerely,
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  #2  
Old March 12th 09, 01:24 AM posted to sci.electronics.repair
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Posts: 1,178
Default Zenith Sentry TV/Monitor

On Mar 7, 4:18*pm, "J.B. Wood" wrote:
Hello, all. *I have a circa 1991 Zenith Sentry 2 TV model SJ206585 that
still has a great picture but there are diagonal lines (not retrace
lines)

Those are horizontal retrace lines occurring during the vertical
retrace interval. If you can find the 'blanking' adjustment, tweak
it.

If there's no blanking adjustment, it's time to tweak the high
voltage
adjustment called (usually) 'screen'. It's likely that contrast
will get lots better when this is done correctly. Don't let
the shadow detail get lost, though.
  #3  
Old March 12th 09, 11:37 AM posted to sci.electronics.repair
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Posts: 12
Default Zenith Sentry TV/Monitor

In article
,
whit3rd wrote:

On Mar 7, 4:18=A0pm, "J.B. Wood" wrote:
Hello, all. =A0I have a circa 1991 Zenith Sentry 2 TV model SJ206585 that
still has a great picture but there are diagonal lines (not retrace
lines)

Those are horizontal retrace lines occurring during the vertical
retrace interval. If you can find the 'blanking' adjustment, tweak
it.

If there's no blanking adjustment, it's time to tweak the high
voltage
adjustment called (usually) 'screen'. It's likely that contrast
will get lots better when this is done correctly. Don't let
the shadow detail get lost, though.


Hello, and thanks for taking the time. But as I pointed out in my OP they
are definitely not retrace lines. The lines are grouped into sets of a
specific pattern and that are inclined at an angle (relative to
horizontal) much greater than that observed with retrace lines. Some
Googling on Sentry model sets indicates that a capacitor may be the
culprit reponsible for the picture artifacts. I realize it's difficult to
provide advice when one can't see the actual pattern but again, thanks.
Sincerely,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337
  #4  
Old March 13th 09, 01:15 PM posted to sci.electronics.repair
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Posts: 20
Default Zenith Sentry TV/Monitor

J. B. Wood wrote:
In article
,
whit3rd wrote:

On Mar 7, 4:18=A0pm, "J.B. Wood" wrote:
Hello, all. =A0I have a circa 1991 Zenith Sentry 2 TV model SJ206585 that
still has a great picture but there are diagonal lines (not retrace
lines)

Those are horizontal retrace lines occurring during the vertical
retrace interval. If you can find the 'blanking' adjustment, tweak
it.

If there's no blanking adjustment, it's time to tweak the high
voltage
adjustment called (usually) 'screen'. It's likely that contrast
will get lots better when this is done correctly. Don't let
the shadow detail get lost, though.


Hello, and thanks for taking the time. But as I pointed out in my OP they
are definitely not retrace lines. The lines are grouped into sets of a
specific pattern and that are inclined at an angle (relative to
horizontal) much greater than that observed with retrace lines. Some
Googling on Sentry model sets indicates that a capacitor may be the
culprit reponsible for the picture artifacts. I realize it's difficult to
provide advice when one can't see the actual pattern but again, thanks.
Sincerely,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337



If their not retrace lines, brightness too high, bias on crt to
high I'm taking that this is a crt set how wide are these lines are they
colored lines if you think it might be a capacitor problem why not go
through it with a esr meter.
 




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