Mitsubishi CS-2655R vertical jitter.

D

David Farber

Guest
This Mitsubishi CS-2655R tv came into the shop with a blurry picture and not
much else wrong. I touched up the focus control and the picture is crystal
clear except for some slight vertical jitter. I replaced all the C400 series
electrolytic caps and the vertical output IC, AN5521. The jitter is apparent
whether you are watching a tv program or viewing the on screen display menus. A
Google search for this fault didn't turn up much.

Thanks for your reply.


David Farber
David Farber's Service Center
L.A., CA
 
check for leaky low value caps in the vicinity of the jungle IC; I remember
seeing one doing this, but I don't have the scheme, and can't remember which
one it was
 
Change all the caps on the PIP assembly if your set has one. Clean the
debris off the traces and check them for being destroyed by the electrolyte
from the caps. Then check and change the rest of them on the main board
including those near the jungle ic that even check questionable. .
"BWL" <btvfxer@aol.com> wrote in message
news:20040429154819.10191.00000599@mb-m14.aol.com...
check for leaky low value caps in the vicinity of the jungle IC; I
remember
seeing one doing this, but I don't have the scheme, and can't remember
which
one it was
Click to expand...
 
Check all the caps from the beginning of the video path, through to
the sync separator circuits, and on to the sync amp, and then to the
vertical deflection generator.

Any loss of low frequency response in this path will cause the
vertical sync reference to be a bit low.

If you have a scope, set the timebase to see the frame rate, and
follow through for any tilt in the blanking, and or pulse supression
where the sync is stripped off.

Jerry G.
========


farberbear@aol.com (David Farber) wrote in message news:<20040429134841.17518.00000349@mb-m03.aol.com>...
This Mitsubishi CS-2655R tv came into the shop with a blurry picture and not
much else wrong. I touched up the focus control and the picture is crystal
clear except for some slight vertical jitter. I replaced all the C400 series
electrolytic caps and the vertical output IC, AN5521. The jitter is apparent
whether you are watching a tv program or viewing the on screen display menus. A
Google search for this fault didn't turn up much.

Thanks for your reply.


David Farber
David Farber's Service Center
L.A., CA
Click to expand...
 
Not on this set...no PIP module. Look for a bad coupling cap in the video
path or a bad filter cap on one of the supplies.

Leonard

"Art" <stubby@comcast.net> wrote in message
news:AKadnemUgYcV-wzdRVn-hA@comcast.com...
Change all the caps on the PIP assembly if your set has one. Clean the
debris off the traces and check them for being destroyed by the
electrolyte
from the caps. Then check and change the rest of them on the main board
including those near the jungle ic that even check questionable. .
"BWL" <btvfxer@aol.com> wrote in message
news:20040429154819.10191.00000599@mb-m14.aol.com...
check for leaky low value caps in the vicinity of the jungle IC; I
remember
seeing one doing this, but I don't have the scheme, and can't remember
which
one it was
Click to expand...
 
On 29 Apr 2004 17:48:41 GMT, farberbear@aol.com (David Farber) wrote:

This Mitsubishi CS-2655R tv came into the shop with a blurry picture and not
much else wrong. I touched up the focus control and the picture is crystal
clear except for some slight vertical jitter. I replaced all the C400 series
electrolytic caps and the vertical output IC, AN5521. The jitter is apparent
whether you are watching a tv program or viewing the on screen display menus. A
Google search for this fault didn't turn up much.

Thanks for your reply.


David Farber
David Farber's Service Center
L.A., CA
Click to expand...
You need to clean the main circuit board, top and bottom, particularly
the video section after replacing the faulty capacitors. I have had
board leakage cause vertical jitter multiple times. Chuck
 
Don't forget to get all the yellow/brown glue off everything.

Good Luck,
Bill Jr


"Chuck" <ch@deja.net> wrote in message
news:49l490d7iiaoo02ue9t8frgsmmg7sge40e@4ax.com...
On 29 Apr 2004 17:48:41 GMT, farberbear@aol.com (David Farber) wrote:

This Mitsubishi CS-2655R tv came into the shop with a blurry picture and
not
much else wrong. I touched up the focus control and the picture is
crystal
clear except for some slight vertical jitter. I replaced all the C400
series
electrolytic caps and the vertical output IC, AN5521. The jitter is
apparent
whether you are watching a tv program or viewing the on screen display
menus. A
Google search for this fault didn't turn up much.

Thanks for your reply.


David Farber
David Farber's Service Center
L.A., CA


You need to clean the main circuit board, top and bottom, particularly
the video section after replacing the faulty capacitors. I have had
board leakage cause vertical jitter multiple times. Chuck
Click to expand...
 
I'm not making much progress here. Every cap I've checked has acceptable ESR
and that goes for the ones I initially replaced. None of them shows any signs
of leakage. I've scraped off some minor glue deposits in a couple of areas. The
picture still jitters.

One weird phenomenon occurs when I use an external video input. If I send a
crosshatch pattern in through the video input, the TV shuts down after a few
seconds. The same crosshatch pattern sent through the RF input does not shut
the TV down. A color bar pattern sent to the video input does not shut the TV
down. There is an X-Ray check toggle switch which I thought had been moved to
the "check" position but trying it in the other position makes no difference.
(Sometimes these plastic toggle switches have three positions even though there
are only two selections.)

Thanks for everyone's suggestions so far. I'll keep plugging away at this.

Regards,
David Farber


Subject: Re: Mitsubishi CS-2655R vertical jitter.
From: "Bill Jr" bill@nospam.usa2net.net
Date: 04/30/2004 3:21 PM Pacific Daylight Time
Message-id: <4kAkc.533892$Po1.465339@twister.tampabay.rr.com

Don't forget to get all the yellow/brown glue off everything.

Good Luck,
Bill Jr


"Chuck" <ch@deja.net> wrote in message
news:49l490d7iiaoo02ue9t8frgsmmg7sge40e@4ax.com...
On 29 Apr 2004 17:48:41 GMT, farberbear@aol.com (David Farber) wrote:

This Mitsubishi CS-2655R tv came into the shop with a blurry picture and
not
much else wrong. I touched up the focus control and the picture is
crystal
clear except for some slight vertical jitter. I replaced all the C400
series
electrolytic caps and the vertical output IC, AN5521. The jitter is
apparent
whether you are watching a tv program or viewing the on screen display
menus. A
Google search for this fault didn't turn up much.

Thanks for your reply.


David Farber
David Farber's Service Center
L.A., CA


You need to clean the main circuit board, top and bottom, particularly
the video section after replacing the faulty capacitors. I have had
board leakage cause vertical jitter multiple times. Chuck
Click to expand...

David Farber
David Farber's Service Center
L.A., CA
 
David Farber wrote:
I'm not making much progress here. Every cap I've checked has acceptable
ESR and that goes for the ones I initially replaced.
Click to expand...
You've probably already checked this, but it needs to be said: Even if their
ESR is just fine, if one or more of them are no longer acting as
capacitors, they could cause symptoms.

--
John Miller
Email address: domain, n4vu.com; username, jsm

The opposite of talking isn't listening. The opposite of talking is
waiting.
-Fran Lebowitz, "Social Studies"
 
David,

This is not one of the sets that has lots of bad caps. This one is more
likely to have some caps that may be low in capacitance due to age than lots
of high ESR or physically leaky ones. I'd be checking them with a
capacitance meter or looking at the response of the circuit in addition to
ESR checks. Look at the output from the regulators with a scope and see if
they are noisy. Like Bill said, look for any old glue on the board. Some
of these old sets had some glue that dried out and absorbed moisture from
the air after years in service and this would cause some strange symptoms
that have caused many techs to chase their tails.

Leonard

"David Farber" <farberbear@aol.com> wrote in message
news:20040430191211.12062.00000669@mb-m02.aol.com...
I'm not making much progress here. Every cap I've checked has acceptable
ESR
and that goes for the ones I initially replaced. None of them shows any
signs
of leakage. I've scraped off some minor glue deposits in a couple of
areas. The
picture still jitters.

One weird phenomenon occurs when I use an external video input. If I send
a
crosshatch pattern in through the video input, the TV shuts down after a
few
seconds. The same crosshatch pattern sent through the RF input does not
shut
the TV down. A color bar pattern sent to the video input does not shut the
TV
down. There is an X-Ray check toggle switch which I thought had been moved
to
the "check" position but trying it in the other position makes no
difference.
(Sometimes these plastic toggle switches have three positions even though
there
are only two selections.)

Thanks for everyone's suggestions so far. I'll keep plugging away at this.

Regards,
David Farber


Subject: Re: Mitsubishi CS-2655R vertical jitter.
From: "Bill Jr" bill@nospam.usa2net.net
Date: 04/30/2004 3:21 PM Pacific Daylight Time
Message-id: <4kAkc.533892$Po1.465339@twister.tampabay.rr.com

Don't forget to get all the yellow/brown glue off everything.

Good Luck,
Bill Jr


"Chuck" <ch@deja.net> wrote in message
news:49l490d7iiaoo02ue9t8frgsmmg7sge40e@4ax.com...
On 29 Apr 2004 17:48:41 GMT, farberbear@aol.com (David Farber) wrote:

This Mitsubishi CS-2655R tv came into the shop with a blurry picture
and
not
much else wrong. I touched up the focus control and the picture is
crystal
clear except for some slight vertical jitter. I replaced all the C400
series
electrolytic caps and the vertical output IC, AN5521. The jitter is
apparent
whether you are watching a tv program or viewing the on screen display
menus. A
Google search for this fault didn't turn up much.

Thanks for your reply.


David Farber
David Farber's Service Center
L.A., CA


You need to clean the main circuit board, top and bottom, particularly
the video section after replacing the faulty capacitors. I have had
board leakage cause vertical jitter multiple times. Chuck




David Farber
David Farber's Service Center
L.A., CA
Click to expand...
 
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