Hello,
I can't be the only one seeing this problem.
Have a JVC Model AV-27230 with what looks like a collapsing Vertical
Screen at the top, similar to what you'd see when a Vertical Output IC
goes sour on most sets. In this case though it is Translucent, most of
the time, on most channels/backgrounds. Occasionally it is collapsed at
the top in the traditional sense, as in it's not Translucent, but
Black where it's collapsed.
Doesn't matter what is used for a video source or what input source is
used, e.g RF / Tuner, Video 1, Video2, etc.
If I wasn't so picky I could probably live with it when it's
Translucent, but you know how that goes..

Found this someplace else regarding how to get in to Service mode on
JVC Sets...a bit hesitat to try tweaking anything until I understand
what is going on here...e.g.- Could it have something to do with the
Vertical Deflection on the Yoke??

Bill


"With TV powered ON press: [DISPLAY] and [VIDEO STATUS] on the remote
at the same time.

-or-
Press the [SLEEP TIMER] key and set the SLEEP TIMER for "0" MIN. While
the SLEEP TIMER information is still on screen, press the [DISPLAY] key
and [VIDEO STATUS] key of the remote control unit at the same time to
enter the SERVICE MENU.

Exit the service menu by twice pressing the [EXIT] key on the remote.

If you're attempting to adjust color or geometry errors, you'll need
the Video Essentials DVD, Laser Disc or some other source of test
material."

You should do an ESR test on all the capacitors in the vertical
deflection amp section. It is common to have caps going defective that
cause your described fault condition.


Jerry G.
======

Thanks for the quick reply Jerry, I'll go there first.
Will let ya know how I make out. Makes sense, as
complete Vert Output Circuit Failure usually results in a catostrophic
failure, as in completely collapsed.

I'm not looking at the set at the moment, but are ya talkin
Electrolytics
as a common defective cap or what?? Those are easiest to test with
my limited test equipment. Most likely to leave a factory as "walking
wounded"
too I would think.

Bill

Replace......do not bother to check C424 & C425

That should alleviate the problem.


=================================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
(860)399-1861
(860)664-3535 FAX

=================================
"majortom" wrote in message
oups.com...
Hello,
I can't be the only one seeing this problem.
Have a JVC Model AV-27230 with what looks like a collapsing Vertical
Screen at the top, similar to what you'd see when a Vertical Output IC
goes sour on most sets. In this case though it is Translucent, most of
the time, on most channels/backgrounds. Occasionally it is collapsed at
the top in the traditional sense, as in it's not Translucent, but
Black where it's collapsed.
Doesn't matter what is used for a video source or what input source is
used, e.g RF / Tuner, Video 1, Video2, etc.
If I wasn't so picky I could probably live with it when it's
Translucent, but you know how that goes..

Found this someplace else regarding how to get in to Service mode on
JVC Sets...a bit hesitat to try tweaking anything until I understand
what is going on here...e.g.- Could it have something to do with the
Vertical Deflection on the Yoke??

Bill


"With TV powered ON press: [DISPLAY] and [VIDEO STATUS] on the remote
at the same time.

-or-
Press the [SLEEP TIMER] key and set the SLEEP TIMER for "0" MIN. While
the SLEEP TIMER information is still on screen, press the [DISPLAY] key
and [VIDEO STATUS] key of the remote control unit at the same time to
enter the SERVICE MENU.

Exit the service menu by twice pressing the [EXIT] key on the remote.

If you're attempting to adjust color or geometry errors, you'll need
the Video Essentials DVD, Laser Disc or some other source of test
material."

majortom:
NO, electrolytics are NOT "easiest to test"..... in circuitry like the
vertical deflection and SMPS; you must test with an ESR meter..... all
other methods do not give you important ESR information that is vital to
proper operation.
If you do not have an ESR meter then just replace all of the electrolytics
near and around the vertical deflection output circuitry, there are only
about a half dozen, fairly cheap to do.
With your JVC television you should pay special attention to c424 and c425
and any other 4xx series electrolytics.
Again, without an ESR meter do not waste your time trying to test, just
replace them.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"majortom" wrote in message
ups.com...
Thanks for the quick reply Jerry, I'll go there first.
Will let ya know how I make out. Makes sense, as
complete Vert Output Circuit Failure usually results in a catostrophic
failure, as in completely collapsed.

I'm not looking at the set at the moment, but are ya talkin
Electrolytics
as a common defective cap or what?? Those are easiest to test with
my limited test equipment. Most likely to leave a factory as "walking
wounded"
too I would think.

Bill

OK I've heard enough, great feedback guys, sounds like a common
problem!!!
Will drag that thing down to the basement over the weekend and get
after it...

Thanks a bunch