Sony TV - Picture Problem

J

John F Miller

Guest
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days ago, it
developed a picture problem. Rather than try to describe it, I have placed
the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes after
cold-starting the set. The problem will persist for a few seconds before
the display completely disappears. Only a cold reset will restore the
image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what I
think is a capacitance issue. Using a painter's stick (wooden!), I tapped
the various components on the main board and found that the tapping could
induce the problem. However, if I hold the ground of the audio connectors,
the tapping does not create the problem. When the problem is present,
grabbing the ground of the audio connector clears the problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I merrily
begin replacing all the capacitors, I would like to know if anyone knows a
specific cause and/or that I am barking up the right tree.

Many thanks in advance,

John Miller.
 
How does tapping on the board narrow it down to a capacitance issue?

Any mechanical vibration testing that changes the symptom points to a
connection problem. It is possible, though highly unlikely, that the
leads to a capacitor have become partially disconnected internally.

I would start by a good visual going over with a light and magnifying
glass the solder connections on the bottom of the board.
 
Thanks for your quick reply.

I suspect a capacitance issue based on the problem not occurring (or even
reversing) when I touch a ground on the board (e.g., the audio input
ground). When tapping, there's no specific component that is most sensitive
and, if, instead of tapping, I apply a more constant force to the
components, I cannot reproduce the problem. I have disconnected and
reconnected all the connectors to the main board with no effect. I have
looked at the underside of the board with a magnifying lamp but couldn't
detect any obvious problems.

John.

<dkuhajda@locl.net> wrote in message
news:1140999347.813624.248880@u72g2000cwu.googlegroups.com...
How does tapping on the board narrow it down to a capacitance issue?

Any mechanical vibration testing that changes the symptom points to a
connection problem. It is possible, though highly unlikely, that the
leads to a capacitor have become partially disconnected internally.

I would start by a good visual going over with a light and magnifying
glass the solder connections on the bottom of the board.
Click to expand...
 
John F Miller wrote:
Thanks for your quick reply.

I suspect a capacitance issue based on the problem not occurring (or even
reversing) when I touch a ground on the board (e.g., the audio input
ground). When tapping, there's no specific component that is most sensitive
and, if, instead of tapping, I apply a more constant force to the
components, I cannot reproduce the problem. I have disconnected and
reconnected all the connectors to the main board with no effect. I have
looked at the underside of the board with a magnifying lamp but couldn't
detect any obvious problems.

John.

dkuhajda@locl.net> wrote in message
news:1140999347.813624.248880@u72g2000cwu.googlegroups.com...
How does tapping on the board narrow it down to a capacitance issue?

Any mechanical vibration testing that changes the symptom points to a
connection problem. It is possible, though highly unlikely, that the
leads to a capacitor have become partially disconnected internally.

I would start by a good visual going over with a light and magnifying
glass the solder connections on the bottom of the board.
Click to expand...
Sonys from this period had a solder problem esp around the tuner and
tuner board. I repaired a few recently with this problem. Sam talks
about it here:
http://www.eio.com/repairfaq/REPAIR/F_sonytune.html
Very careful inspection is a must. Some of the solder might have to be
sucked off and replaced. The bad joints have a frosted look with a
grainy look and sometimes veins running through them. I usually reheat
everything and resolder everything that looks bad. Quite tedious. Just
did an eMac with the same problem.
richard
 
Thanks! I will check that area very carefully.

John.


"spudnuty" <spudnuty@lycos.com> wrote in message
news:1141015313.818952.246060@e56g2000cwe.googlegroups.com...
John F Miller wrote:
Thanks for your quick reply.

I suspect a capacitance issue based on the problem not occurring (or even
reversing) when I touch a ground on the board (e.g., the audio input
ground). When tapping, there's no specific component that is most
sensitive
and, if, instead of tapping, I apply a more constant force to the
components, I cannot reproduce the problem. I have disconnected and
reconnected all the connectors to the main board with no effect. I have
looked at the underside of the board with a magnifying lamp but couldn't
detect any obvious problems.

John.

dkuhajda@locl.net> wrote in message
news:1140999347.813624.248880@u72g2000cwu.googlegroups.com...
How does tapping on the board narrow it down to a capacitance issue?

Any mechanical vibration testing that changes the symptom points to a
connection problem. It is possible, though highly unlikely, that the
leads to a capacitor have become partially disconnected internally.

I would start by a good visual going over with a light and magnifying
glass the solder connections on the bottom of the board.

Sonys from this period had a solder problem esp around the tuner and
tuner board. I repaired a few recently with this problem. Sam talks
about it here:
http://www.eio.com/repairfaq/REPAIR/F_sonytune.html
Very careful inspection is a must. Some of the solder might have to be
sucked off and replaced. The bad joints have a frosted look with a
grainy look and sometimes veins running through them. I usually reheat
everything and resolder everything that looks bad. Quite tedious. Just
did an eMac with the same problem.
richard
Click to expand...
 
I like those do it yourself guys. They mess up then they bring it in
to us and it ends up costing more to have it fixed now then as it
would if they would of came in before messing with it.
 
Resolder your vertical output IC561.

This will solve your problem.

Resolder the Horizontal Driver Transformer while your in there for good
preventive maintenance


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"John F Miller" <johnATenosoft.net> wrote in message
news:1204f9n7ikiugd0@corp.supernews.com...
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days ago, it
developed a picture problem. Rather than try to describe it, I have
placed the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes after
cold-starting the set. The problem will persist for a few seconds before
the display completely disappears. Only a cold reset will restore the
image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what I
think is a capacitance issue. Using a painter's stick (wooden!), I tapped
the various components on the main board and found that the tapping could
induce the problem. However, if I hold the ground of the audio
connectors, the tapping does not create the problem. When the problem is
present, grabbing the ground of the audio connector clears the problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I
merrily begin replacing all the capacitors, I would like to know if anyone
knows a specific cause and/or that I am barking up the right tree.

Many thanks in advance,

John Miller.
Click to expand...
 
Based on his description (problem shows for a while then screen disappears)
the protection circuitry is kicking in to blank the picture. A loose
connection (or bad solder joint) can definitely cause this. If not a solder
joint problem, it is doubtful that a component failure problem would allow
him to get a normal picture to submit.

I have a Sony KP-41T15 that has a similar "line paring" problem but in my
case there are faulty components in the vertical circuit as the problem
condition is continuous from when the set is turned on. The vertical
voltage feed to the jungle IC is twice what it should be (approx 3V versus
1.5V). I am suspecting the jungle IC as well but first I have to find the
problem components(s).

Bruce


"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:8CYMf.3031$%m4.609@newssvr33.news.prodigy.com...
Resolder your vertical output IC561.

This will solve your problem.

Resolder the Horizontal Driver Transformer while your in there for good
preventive maintenance


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"John F Miller" <johnATenosoft.net> wrote in message
news:1204f9n7ikiugd0@corp.supernews.com...
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days ago,
it developed a picture problem. Rather than try to describe it, I have
placed the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes
after cold-starting the set. The problem will persist for a few seconds
before the display completely disappears. Only a cold reset will restore
the image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what I
think is a capacitance issue. Using a painter's stick (wooden!), I
tapped the various components on the main board and found that the
tapping could induce the problem. However, if I hold the ground of the
audio connectors, the tapping does not create the problem. When the
problem is present, grabbing the ground of the audio connector clears the
problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I
merrily begin replacing all the capacitors, I would like to know if
anyone knows a specific cause and/or that I am barking up the right tree.

Many thanks in advance,

John Miller.
Click to expand...
 
Jungle IC301 CXA1477 is your line pairing culprit.

Best place to buy these are from B & D http://www.bdent.com/

Original Sony IC's in Original Sony packaging. Around $50.00

Yeah...you can scrounge them up for $20 or so here and there.....but once ya
ya bit by a bad one or one that lasts a couple days....OEM is the only way
to go on these.


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"Bruce H" <joanlh@mts.net> wrote in message
news:FAmNf.16396$5r5.693@newsfe17.lga...
Correction to post:

"Bruce H" <joanlh@mts.net> wrote in message news:...
Based on his description (problem shows for a while then screen
disappears) the protection circuitry is kicking in to blank the picture.
A loose connection (or bad solder joint) can definitely cause this. If
not a solder joint problem, it is doubtful that a component failure
problem would allow him to get a normal picture to submit.

I have a Sony KP-41T15 that has a similar "line paring" problem but in my
case there are faulty components in the vertical circuit as the problem
condition is continuous from when the set is turned on. The vertical
voltage feed to the jungle IC is below what it should be (approx 3V
versus 3.6V). I am suspecting the jungle IC as well but first I have to
find the problem components(s).

Bruce


"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:8CYMf.3031$%m4.609@newssvr33.news.prodigy.com...
Resolder your vertical output IC561.

This will solve your problem.

Resolder the Horizontal Driver Transformer while your in there for good
preventive maintenance


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"John F Miller" <johnATenosoft.net> wrote in message
news:1204f9n7ikiugd0@corp.supernews.com...
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days ago,
it developed a picture problem. Rather than try to describe it, I have
placed the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes
after cold-starting the set. The problem will persist for a few
seconds before the display completely disappears. Only a cold reset
will restore the image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what
I think is a capacitance issue. Using a painter's stick (wooden!), I
tapped the various components on the main board and found that the
tapping could induce the problem. However, if I hold the ground of the
audio connectors, the tapping does not create the problem. When the
problem is present, grabbing the ground of the audio connector clears
the problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I
merrily begin replacing all the capacitors, I would like to know if
anyone knows a specific cause and/or that I am barking up the right
tree.

Many thanks in advance,

John Miller.
Click to expand...
 
Thanks for the link, Jeff! I'll get around to this and report back (some
time after I replace the plumbing in my house and install the insulation on
the exterior walls).

So far all the supply voltages seem to be approximately where they need to
be but I may have a leaky transistor. Don't want to bug anyone until I do
some proper investigation...

Bruce


"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:3kHNf.2729$XP7.693@newssvr31.news.prodigy.com...
Jungle IC301 CXA1477 is your line pairing culprit.

Best place to buy these are from B & D http://www.bdent.com/

Original Sony IC's in Original Sony packaging. Around $50.00

Yeah...you can scrounge them up for $20 or so here and there.....but once
ya ya bit by a bad one or one that lasts a couple days....OEM is the only
way to go on these.


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"Bruce H" <joanlh@mts.net> wrote in message
news:FAmNf.16396$5r5.693@newsfe17.lga...
Correction to post:

"Bruce H" <joanlh@mts.net> wrote in message news:...
Based on his description (problem shows for a while then screen
disappears) the protection circuitry is kicking in to blank the picture.
A loose connection (or bad solder joint) can definitely cause this. If
not a solder joint problem, it is doubtful that a component failure
problem would allow him to get a normal picture to submit.

I have a Sony KP-41T15 that has a similar "line paring" problem but in
my case there are faulty components in the vertical circuit as the
problem condition is continuous from when the set is turned on. The
vertical voltage feed to the jungle IC is below what it should be
(approx 3V versus 3.6V). I am suspecting the jungle IC as well but
first I have to find the problem components(s).

Bruce


"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:8CYMf.3031$%m4.609@newssvr33.news.prodigy.com...
Resolder your vertical output IC561.

This will solve your problem.

Resolder the Horizontal Driver Transformer while your in there for good
preventive maintenance


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"John F Miller" <johnATenosoft.net> wrote in message
news:1204f9n7ikiugd0@corp.supernews.com...
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days
ago, it developed a picture problem. Rather than try to describe it,
I have placed the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes
after cold-starting the set. The problem will persist for a few
seconds before the display completely disappears. Only a cold reset
will restore the image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what
I think is a capacitance issue. Using a painter's stick (wooden!), I
tapped the various components on the main board and found that the
tapping could induce the problem. However, if I hold the ground of
the audio connectors, the tapping does not create the problem. When
the problem is present, grabbing the ground of the audio connector
clears the problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I
merrily begin replacing all the capacitors, I would like to know if
anyone knows a specific cause and/or that I am barking up the right
tree.

Many thanks in advance,

John Miller.
Click to expand...
 
Just a follow up to my television problem (Sony KP-41T15).
I bought the Jungle IC from B & D and it solved the problem.
Interesting that the plastic in this set is very fragile
and cracks easily. I used slivers of ABS pipe and ABS/PVC
solvent to repair cracks.

My next task is to set the convergence (particularly the red
CRT gun as I had to replace it). Swapped the yolk and
positioned it as close to the original as possible.
Everything works except the picture is a little out.

Just wanted to say thanks for the information.

Bruce


Bruce H wrote:
Thanks for the link, Jeff! I'll get around to this and report back (some
time after I replace the plumbing in my house and install the insulation on
the exterior walls).

So far all the supply voltages seem to be approximately where they need to
be but I may have a leaky transistor. Don't want to bug anyone until I do
some proper investigation...

Bruce


"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:3kHNf.2729$XP7.693@newssvr31.news.prodigy.com...
Jungle IC301 CXA1477 is your line pairing culprit.

Best place to buy these are from B & D http://www.bdent.com/

Original Sony IC's in Original Sony packaging. Around $50.00

Yeah...you can scrounge them up for $20 or so here and there.....but once
ya ya bit by a bad one or one that lasts a couple days....OEM is the only
way to go on these.


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"Bruce H" <joanlh@mts.net> wrote in message
news:FAmNf.16396$5r5.693@newsfe17.lga...
Correction to post:

"Bruce H" <joanlh@mts.net> wrote in message news:...
Based on his description (problem shows for a while then screen
disappears) the protection circuitry is kicking in to blank the picture.
A loose connection (or bad solder joint) can definitely cause this. If
not a solder joint problem, it is doubtful that a component failure
problem would allow him to get a normal picture to submit.

I have a Sony KP-41T15 that has a similar "line paring" problem but in
my case there are faulty components in the vertical circuit as the
problem condition is continuous from when the set is turned on. The
vertical voltage feed to the jungle IC is below what it should be
(approx 3V versus 3.6V). I am suspecting the jungle IC as well but
first I have to find the problem components(s).

Bruce


"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:8CYMf.3031$%m4.609@newssvr33.news.prodigy.com...
Resolder your vertical output IC561.

This will solve your problem.

Resolder the Horizontal Driver Transformer while your in there for good
preventive maintenance


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"John F Miller" <johnATenosoft.net> wrote in message
news:1204f9n7ikiugd0@corp.supernews.com...
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days
ago, it developed a picture problem. Rather than try to describe it,
I have placed the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes
after cold-starting the set. The problem will persist for a few
seconds before the display completely disappears. Only a cold reset
will restore the image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what
I think is a capacitance issue. Using a painter's stick (wooden!), I
tapped the various components on the main board and found that the
tapping could induce the problem. However, if I hold the ground of
the audio connectors, the tapping does not create the problem. When
the problem is present, grabbing the ground of the audio connector
clears the problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I
merrily begin replacing all the capacitors, I would like to know if
anyone knows a specific cause and/or that I am barking up the right
tree.

Many thanks in advance,

John Miller.
Click to expand...
 
Correction to post:

"Bruce H" <joanlh@mts.net> wrote in message news:...
Based on his description (problem shows for a while then screen
disappears) the protection circuitry is kicking in to blank the picture.
A loose connection (or bad solder joint) can definitely cause this. If
not a solder joint problem, it is doubtful that a component failure
problem would allow him to get a normal picture to submit.

I have a Sony KP-41T15 that has a similar "line paring" problem but in my
case there are faulty components in the vertical circuit as the problem
condition is continuous from when the set is turned on. The vertical
voltage feed to the jungle IC is below what it should be (approx 3V versus
3.6V). I am suspecting the jungle IC as well but first I have to find the
problem components(s).

Bruce


"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:8CYMf.3031$%m4.609@newssvr33.news.prodigy.com...
Resolder your vertical output IC561.

This will solve your problem.

Resolder the Horizontal Driver Transformer while your in there for good
preventive maintenance


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"John F Miller" <johnATenosoft.net> wrote in message
news:1204f9n7ikiugd0@corp.supernews.com...
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days ago,
it developed a picture problem. Rather than try to describe it, I have
placed the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes
after cold-starting the set. The problem will persist for a few seconds
before the display completely disappears. Only a cold reset will
restore the image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what I
think is a capacitance issue. Using a painter's stick (wooden!), I
tapped the various components on the main board and found that the
tapping could induce the problem. However, if I hold the ground of the
audio connectors, the tapping does not create the problem. When the
problem is present, grabbing the ground of the audio connector clears
the problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I
merrily begin replacing all the capacitors, I would like to know if
anyone knows a specific cause and/or that I am barking up the right
tree.

Many thanks in advance,

John Miller.
Click to expand...
 
Have you done what Jeff suggests ?

kip
"Bruce H" <joanlh@mts.net> wrote in message
news:FAmNf.16396$5r5.693@newsfe17.lga...
Correction to post:

"Bruce H" <joanlh@mts.net> wrote in message news:...
Based on his description (problem shows for a while then screen
disappears) the protection circuitry is kicking in to blank the picture.
A loose connection (or bad solder joint) can definitely cause this. If
not a solder joint problem, it is doubtful that a component failure
problem would allow him to get a normal picture to submit.

I have a Sony KP-41T15 that has a similar "line paring" problem but in my
case there are faulty components in the vertical circuit as the problem
condition is continuous from when the set is turned on. The vertical
voltage feed to the jungle IC is below what it should be (approx 3V
versus 3.6V). I am suspecting the jungle IC as well but first I have to
find the problem components(s).

Bruce


"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:8CYMf.3031$%m4.609@newssvr33.news.prodigy.com...
Resolder your vertical output IC561.

This will solve your problem.

Resolder the Horizontal Driver Transformer while your in there for good
preventive maintenance


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"John F Miller" <johnATenosoft.net> wrote in message
news:1204f9n7ikiugd0@corp.supernews.com...
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days ago,
it developed a picture problem. Rather than try to describe it, I have
placed the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes
after cold-starting the set. The problem will persist for a few
seconds before the display completely disappears. Only a cold reset
will restore the image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what
I think is a capacitance issue. Using a painter's stick (wooden!), I
tapped the various components on the main board and found that the
tapping could induce the problem. However, if I hold the ground of the
audio connectors, the tapping does not create the problem. When the
problem is present, grabbing the ground of the audio connector clears
the problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I
merrily begin replacing all the capacitors, I would like to know if
anyone knows a specific cause and/or that I am barking up the right
tree.

Many thanks in advance,

John Miller.
Click to expand...
 
Thanks, Jeff!

I followed your suggestions yesterday and, after being on continuously for
more than 20 hours, the problem seems to have gone away.

Regards,

John.

--
John F. Miller
http://www.enosoft.net
high performance tools for music and video


"Shoreline Electronics" <jstielau@snet.net> wrote in message
news:8CYMf.3031$%m4.609@newssvr33.news.prodigy.com...
Resolder your vertical output IC561.

This will solve your problem.

Resolder the Horizontal Driver Transformer while your in there for good
preventive maintenance


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
jstielau@snet.net
========================

"John F Miller" <johnATenosoft.net> wrote in message
news:1204f9n7ikiugd0@corp.supernews.com...
Hello,

I have a Sony Trinitron KV27S22 (December 1997). A couple of days ago,
it developed a picture problem. Rather than try to describe it, I have
placed the following photos on the web:

Image of color bars: Behaving OK -
http://www.enosoft.net/kv27s22/Bars%20-%20OK.JPG
Image of color bars: Exhibiting problem -
http://www.enosoft.net/kv27s22/Bars%20-%20Problem.JPG

The problem will set in anything from a few seconds to a few minutes
after cold-starting the set. The problem will persist for a few seconds
before the display completely disappears. Only a cold reset will restore
the image. Audio is fine.

I have done some troubleshooting and have narrowed the problem to what I
think is a capacitance issue. Using a painter's stick (wooden!), I
tapped the various components on the main board and found that the
tapping could induce the problem. However, if I hold the ground of the
audio connectors, the tapping does not create the problem. When the
problem is present, grabbing the ground of the audio connector clears the
problem.

The most sensitive part of the board is shown at:

http://www.enosoft.net/kv27s22/Main%20Board%20(Part).JPG

I have a copy of the Sony service manual for this set but, before I
merrily begin replacing all the capacitors, I would like to know if
anyone knows a specific cause and/or that I am barking up the right tree.

Many thanks in advance,

John Miller.
Click to expand...
 
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