Philips widescreen tv overbright on reds....

B

Bonge Boo!

Guest
I've bought a Philips 24PW6324 second hand, lovely TV, except:

After about 1/2 hour use the brightness on the red gun seems to increase
massively, leading to very red/orange skin tones and blurred red images. If
I look at some white text, it seems to have a red halo pushed up and to
right about 1/4 inch. White still stays white, and blues and greens look
normal.

When the TV is not doing this, I think I can see some cycling up and down of
the brightness on the red gun.

Anyone any general suggestions as to what might be wrong, before I call my
local electrical shop and see if they might have a look at it?
 
You will have to have someone who knows the Philips set to service it at the
component level for you.

There are most likely some parts that have become thermo sensitive with age.
The fault is most likely in the video path in the respective colour channel
that is causing the fault. Going by your description, I doubt the CRT is
bad, therefore the service cost should be relatively reasonable.

This is why before buying any used TV, it should be properly checked before
paying out for it. Sometimes a repair cost can add enough to the price to
make the total cost to be around the cost of buying a new set.

From many years of experience, I found that people normally sell their old
TV set when they have a problem with it. A TV is usually the type of device
that when it works properly there is no reason to change it. When the set is
more than about 5 years of age, it generally may not be worth to service.
The cost of servicing can easily cost more than the effective value of the
set. After investing money in to an older set, there are hundreds of other
parts inside, that can easily fail from age and use.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Bonge Boo!" <sweetapple@localhost.com> wrote in message
news:BC1DDB2F.5A835%sweetapple@localhost.com...
I've bought a Philips 24PW6324 second hand, lovely TV, except:

After about 1/2 hour use the brightness on the red gun seems to increase
massively, leading to very red/orange skin tones and blurred red images. If
I look at some white text, it seems to have a red halo pushed up and to
right about 1/4 inch. White still stays white, and blues and greens look
normal.

When the TV is not doing this, I think I can see some cycling up and down of
the brightness on the red gun.

Anyone any general suggestions as to what might be wrong, before I call my
local electrical shop and see if they might have a look at it?
 
*Bonge Boo!* a écrit/schreef/wrote le/op/on 4/01/2004 :
I've bought a Philips 24PW6324 second hand, lovely TV, except:

After about 1/2 hour use the brightness on the red gun seems to increase
massively, leading to very red/orange skin tones and blurred red images. If
I look at some white text, it seems to have a red halo pushed up and to
right about 1/4 inch. White still stays white, and blues and greens look
normal.

When the TV is not doing this, I think I can see some cycling up and down of
the brightness on the red gun.

Anyone any general suggestions as to what might be wrong, before I call my
local electrical shop and see if they might have a look at it?
Click to expand...
It will most probably be the picture tube. Espacially if you have that
kind of halo aroun the text.
Best is to call your service man, because you will have to measure a
lot because deciding that "it is" the pict tube...
Your set is equipped with a chassis A8. This is a *pretty young* tv and
probably worth the expenses.

Normally, Philips provides a "coulance" system and they pay part of the
repair if the set is not older than 3 years. Altough, this is the case
in Belgium.

Bye,

Alain

--
*Alain Beguin*
mailto: http://cerbermail.com/?XiEiqwImaa
Newsreader: _MesNews_ http://mesnews.no-ip.com
 
On 4/1/04 15:38, in article bt9cd7$5cd$1@news.eusc.inter.net, "Jerry G."
<jerryg50@hotmail.com> wrote:

You will have to have someone who knows the Philips set to service it at the
component level for you.

There are most likely some parts that have become thermo sensitive with age.
The fault is most likely in the video path in the respective colour channel
that is causing the fault. Going by your description, I doubt the CRT is
bad, therefore the service cost should be relatively reasonable.

This is why before buying any used TV, it should be properly checked before
paying out for it. Sometimes a repair cost can add enough to the price to
make the total cost to be around the cost of buying a new set.
Click to expand...
Hummm. Lesson learned. I've had a Panasonic that's done nearly 20 years
service. I didn't realise modern TV had these sort of manufacturing probs.
Stupid me. Thank you for your comments, and yes, I probably would have been
better off buying new. Now I have to decide whether to flog it cheap, or
repair what may go bad again.
 
"Bonge Boo!" <sweetapple@localhost.com> wrote in message
news:BC1E0CCC.5AAA3%sweetapple@localhost.com...
On 4/1/04 15:38, in article bt9cd7$5cd$1@news.eusc.inter.net, "Jerry G."
jerryg50@hotmail.com> wrote:

You will have to have someone who knows the Philips set to service it at
the
component level for you.

There are most likely some parts that have become thermo sensitive with
age.
The fault is most likely in the video path in the respective colour
channel
that is causing the fault. Going by your description, I doubt the CRT is
bad, therefore the service cost should be relatively reasonable.

This is why before buying any used TV, it should be properly checked
before
paying out for it. Sometimes a repair cost can add enough to the price
to
make the total cost to be around the cost of buying a new set.

Hummm. Lesson learned. I've had a Panasonic that's done nearly 20 years
service. I didn't realise modern TV had these sort of manufacturing probs.
Stupid me. Thank you for your comments, and yes, I probably would have
been
better off buying new. Now I have to decide whether to flog it cheap, or
repair what may go bad again.
Click to expand...
May as well have it looked at, once repaired it should be about as good as
new, even new stuff isn't particularly reliable anymore.
 
On 4/1/04 18:50, in article 1gZJb.124270$VB2.361037@attbi_s51, "James Sweet"
<jamessweet@hotmail.com> wrote:

This is why before buying any used TV, it should be properly checked
before
paying out for it. Sometimes a repair cost can add enough to the price
to
make the total cost to be around the cost of buying a new set.

Hummm. Lesson learned. I've had a Panasonic that's done nearly 20 years
service. I didn't realise modern TV had these sort of manufacturing probs.
Stupid me. Thank you for your comments, and yes, I probably would have
been
better off buying new. Now I have to decide whether to flog it cheap, or
repair what may go bad again.


May as well have it looked at, once repaired it should be about as good as
new, even new stuff isn't particularly reliable anymore.
Click to expand...
I should also add, as I've just worked it out, that when the reds suddenly
massively increase in luminance, if I switch it to stand-by mode for a 10
seconds, then power it up again, the colour cast has gone. The FAQs mention
de-guassing and colour casts, and I guess on power up the set de-guasses if
its like a computer monitor.

Does this help narrow the problem down, or is it still "could be any number
of things"
 
"Bonge Boo!" <sweetapple@localhost.com> wrote in message
news:BC1E423D.5B303%sweetapple@localhost.com...
On 4/1/04 18:50, in article 1gZJb.124270$VB2.361037@attbi_s51, "James
Sweet"
jamessweet@hotmail.com> wrote:

This is why before buying any used TV, it should be properly checked
before
paying out for it. Sometimes a repair cost can add enough to the
price
to
make the total cost to be around the cost of buying a new set.

Hummm. Lesson learned. I've had a Panasonic that's done nearly 20 years
service. I didn't realise modern TV had these sort of manufacturing
probs.
Stupid me. Thank you for your comments, and yes, I probably would have
been
better off buying new. Now I have to decide whether to flog it cheap,
or
repair what may go bad again.


May as well have it looked at, once repaired it should be about as good
as
new, even new stuff isn't particularly reliable anymore.

I should also add, as I've just worked it out, that when the reds suddenly
massively increase in luminance, if I switch it to stand-by mode for a 10
seconds, then power it up again, the colour cast has gone. The FAQs
mention
de-guassing and colour casts, and I guess on power up the set de-guasses
if
its like a computer monitor.

Does this help narrow the problem down, or is it still "could be any
number
of things"
Click to expand...
What you describe really doesn't sound like a degaussing issue, but you need
to have it looked at by a tech, there's nothing we could tell you here that
would help you fix your set.
 
On 4/1/04 22:44, in article CH0Kb.57002$I07.217157@attbi_s53, "James Sweet"
<jamessweet@hotmail.com> wrote:

What you describe really doesn't sound like a degaussing issue, but you need
to have it looked at by a tech, there's nothing we could tell you here that
would help you fix your set.
Click to expand...
Ok thanks.
 
I've got exactly the same problem on a Philips 28PW5324/05 TV. The TV
is about 3 years old and it started showing the problem around
Christmas when the TV is on up to 14 hours/day.
At first the display started showing red as a kind of burgandy colour.
This would start after about 15 minutes of the TV being switched on.
But the problem got worse after a week or so. When you switched the TV
on it looked fine then after about 2 minutes the red just died.
Sometimes the green and blue would then become really intense then
they would flicker up and down in intensity. If I switched the TV into
standby for a minute then switched it on the red would be back ,
sometimes it died again , sometimes it got really intense and
everything had a pinky hue. In short , the red was all over the place.
I opened the back of the machine and connect a scope to the red signal
going into the tube. I could see the amplitude of the signal go up and
down as the red varied on screen. So I reckon its NOT the tube. I then
hooked the scope probe on the red input to the CRT card (just where
the RGB comes up from the main board). The picture started looking
great and I couldn't get the TV to show the bad screen again. I put
the TV together again and its been showing perfect images for the last
4 days. I'm not saying I've fixed it but I know its not the tube and
whatever I disturbed on the CRT card might be fixed by reflowing all
the joints.
 
"Graeme Browne" <GraemeBrowne43@hotmail.com> wrote in message
news:b2edda6c.0401210916.411c674f@posting.google.com...
I've got exactly the same problem on a Philips 28PW5324/05 TV. The TV
is about 3 years old and it started showing the problem around
Christmas when the TV is on up to 14 hours/day.
At first the display started showing red as a kind of burgandy colour.
This would start after about 15 minutes of the TV being switched on.
But the problem got worse after a week or so. When you switched the TV
on it looked fine then after about 2 minutes the red just died.
Sometimes the green and blue would then become really intense then
they would flicker up and down in intensity. If I switched the TV into
standby for a minute then switched it on the red would be back ,
sometimes it died again , sometimes it got really intense and
everything had a pinky hue. In short , the red was all over the place.
I opened the back of the machine and connect a scope to the red signal
going into the tube. I could see the amplitude of the signal go up and
down as the red varied on screen. So I reckon its NOT the tube. I then
hooked the scope probe on the red input to the CRT card (just where
the RGB comes up from the main board). The picture started looking
great and I couldn't get the TV to show the bad screen again. I put
the TV together again and its been showing perfect images for the last
4 days. I'm not saying I've fixed it but I know its not the tube and
whatever I disturbed on the CRT card might be fixed by reflowing all
the joints.
Click to expand...

I wouldn't rule out the tube just yet, wouldn't a cathode short in the gun
cause the voltage at the red cathode pin to vary with the excessive red on
the screen?
 
FYI it is the tube, 99.9% guaranteed.
Yes, a short in the red would vary the waveform on the red cathode. Add the
fact that the tv is also dealing with Philips version of AKB and you really
get some odd effects.

Philips is well aware of the super high failure rate of the tubes and red
gun problems.

David

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:yPAPb.118622$na.113236@attbi_s04...
"Graeme Browne" <GraemeBrowne43@hotmail.com> wrote in message
news:b2edda6c.0401210916.411c674f@posting.google.com...
I've got exactly the same problem on a Philips 28PW5324/05 TV. The TV
is about 3 years old and it started showing the problem around
Christmas when the TV is on up to 14 hours/day.
At first the display started showing red as a kind of burgandy colour.
This would start after about 15 minutes of the TV being switched on.
But the problem got worse after a week or so. When you switched the TV
on it looked fine then after about 2 minutes the red just died.
Sometimes the green and blue would then become really intense then
they would flicker up and down in intensity. If I switched the TV into
standby for a minute then switched it on the red would be back ,
sometimes it died again , sometimes it got really intense and
everything had a pinky hue. In short , the red was all over the place.
I opened the back of the machine and connect a scope to the red signal
going into the tube. I could see the amplitude of the signal go up and
down as the red varied on screen. So I reckon its NOT the tube. I then
hooked the scope probe on the red input to the CRT card (just where
the RGB comes up from the main board). The picture started looking
great and I couldn't get the TV to show the bad screen again. I put
the TV together again and its been showing perfect images for the last
4 days. I'm not saying I've fixed it but I know its not the tube and
whatever I disturbed on the CRT card might be fixed by reflowing all
the joints.


I wouldn't rule out the tube just yet, wouldn't a cathode short in the gun
cause the voltage at the red cathode pin to vary with the excessive red on
the screen?
Click to expand...
 
"David" <dkuhajda@locl.net.spam> wrote in message
news:400f488e@news.greennet.net...
FYI it is the tube, 99.9% guaranteed.
Yes, a short in the red would vary the waveform on the red cathode. Add
the
fact that the tv is also dealing with Philips version of AKB and you
really
get some odd effects.

Philips is well aware of the super high failure rate of the tubes and red
gun problems.

David
Click to expand...

It really does amaze me how many of these are having this problem, seems
these Philips sets are the next Zenith. A sure way to check would be to
unplug the neck board *then* monitor the cathode voltage at the socket.
 
Almost but not quite a sure way. Due to the internal design of the tubes,
Toshiba's as well, the entire HV will quickly be present on the exposed pins
of the tube and WILL arc out to anything close to it, including the
sensitive electronics on the pcb!!! Been there, done that, seen other techs
in shop not listen to my warnings and destroy the main board as well,
argh!!!!!

To do this REQUIRES the use of a test crt socket that places all the pins,
tied together is ok, of the tube through a resistor, usually 100K and a
couple of watts through a Neon lamp that also has a large resistor in
parallel with it,tied to crt dag ground. This will bleed off the rapid hv
build up on the end of the tube. A dead short to dag
ground is a BAD idea on some tubes as well.

It does not really amaze me how many tubes are failing. The manufactures
keep cutting corners to lower cost and eventually they hit a point where an
unexpected large scale failures start to happen. It tends to go in cycles
between manufactures across the board.

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:GsGPb.117816$I06.840132@attbi_s01...
"David" <dkuhajda@locl.net.spam> wrote in message
news:400f488e@news.greennet.net...
FYI it is the tube, 99.9% guaranteed.
Yes, a short in the red would vary the waveform on the red cathode. Add
the
fact that the tv is also dealing with Philips version of AKB and you
really
get some odd effects.

Philips is well aware of the super high failure rate of the tubes and
red
gun problems.

David


It really does amaze me how many of these are having this problem, seems
these Philips sets are the next Zenith. A sure way to check would be to
unplug the neck board *then* monitor the cathode voltage at the socket.
Click to expand...
 
"David" <dkuhajda@locl.net.spam> wrote in message news:<400f7e1a@news.greennet.net>...
Almost but not quite a sure way. Due to the internal design of the tubes,
Toshiba's as well, the entire HV will quickly be present on the exposed pins
of the tube and WILL arc out to anything close to it, including the
sensitive electronics on the pcb!!! Been there, done that, seen other techs
in shop not listen to my warnings and destroy the main board as well,
argh!!!!!

To do this REQUIRES the use of a test crt socket that places all the pins,
tied together is ok, of the tube through a resistor, usually 100K and a
couple of watts through a Neon lamp that also has a large resistor in
parallel with it,tied to crt dag ground. This will bleed off the rapid hv
build up on the end of the tube. A dead short to dag
ground is a BAD idea on some tubes as well.

It does not really amaze me how many tubes are failing. The manufactures
keep cutting corners to lower cost and eventually they hit a point where an
unexpected large scale failures start to happen. It tends to go in cycles
between manufactures across the board.
Click to expand...
I'm not convinced a short on the cathode would show the behavior I saw
on the scope. The waveform was a 'sawtooth' (not sure of the amplitude
.. I think it was 200V p-p) with pixel data imposed. As the red
fluctuated the amplitude of the pixel data fluctuated in sync. The
sawtooth remained stable. Surely if there was a short in the tube the
whole waveform would be effected ?
"James Sweet" <jamessweet@hotmail.com> wrote in message
news:GsGPb.117816$I06.840132@attbi_s01...

"David" <dkuhajda@locl.net.spam> wrote in message
news:400f488e@news.greennet.net...
FYI it is the tube, 99.9% guaranteed.
Yes, a short in the red would vary the waveform on the red cathode. Add
the
fact that the tv is also dealing with Philips version of AKB and you
really
get some odd effects.

Philips is well aware of the super high failure rate of the tubes and
red
gun problems.

David


It really does amaze me how many of these are having this problem, seems
these Philips sets are the next Zenith. A sure way to check would be to
unplug the neck board *then* monitor the cathode voltage at the socket.
Click to expand...
 
IT is really simple to confirm on way or the other.
Simply cut the trace to the red and green cathode at the pin, or unsolder if
you can guarantee no connection with the pad, then run short jumpers to give
the green gun the red drive and the red gun the green drive. Sure the
pictures color will be all screwed up, but when the failure starts you will
know which it is, the tube or the circuits.

David

"Graeme Browne" <GraemeBrowne43@hotmail.com> wrote in message
news:b2edda6c.0401220219.a4e52ae@posting.google.com...
"David" <dkuhajda@locl.net.spam> wrote in message
news:<400f7e1a@news.greennet.net>...
Almost but not quite a sure way. Due to the internal design of the
tubes,
Toshiba's as well, the entire HV will quickly be present on the exposed
pins
of the tube and WILL arc out to anything close to it, including the
sensitive electronics on the pcb!!! Been there, done that, seen other
techs
in shop not listen to my warnings and destroy the main board as well,
argh!!!!!

To do this REQUIRES the use of a test crt socket that places all the
pins,
tied together is ok, of the tube through a resistor, usually 100K and a
couple of watts through a Neon lamp that also has a large resistor in
parallel with it,tied to crt dag ground. This will bleed off the rapid
hv
build up on the end of the tube. A dead short to dag
ground is a BAD idea on some tubes as well.

It does not really amaze me how many tubes are failing. The
manufactures
keep cutting corners to lower cost and eventually they hit a point where
an
unexpected large scale failures start to happen. It tends to go in
cycles
between manufactures across the board.

I'm not convinced a short on the cathode would show the behavior I saw
on the scope. The waveform was a 'sawtooth' (not sure of the amplitude
. I think it was 200V p-p) with pixel data imposed. As the red
fluctuated the amplitude of the pixel data fluctuated in sync. The
sawtooth remained stable. Surely if there was a short in the tube the
whole waveform would be effected ?

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:GsGPb.117816$I06.840132@attbi_s01...

"David" <dkuhajda@locl.net.spam> wrote in message
news:400f488e@news.greennet.net...
FYI it is the tube, 99.9% guaranteed.
Yes, a short in the red would vary the waveform on the red cathode.
Add
the
fact that the tv is also dealing with Philips version of AKB and you
really
get some odd effects.

Philips is well aware of the super high failure rate of the tubes
and
red
gun problems.

David


It really does amaze me how many of these are having this problem,
seems
these Philips sets are the next Zenith. A sure way to check would be
to
unplug the neck board *then* monitor the cathode voltage at the
socket.
Click to expand...
 
"David" <dkuhajda@locl.net.spam> wrote in message news:<4010929a@news.greennet.net>...
IT is really simple to confirm on way or the other.
Simply cut the trace to the red and green cathode at the pin, or unsolder if
you can guarantee no connection with the pad, then run short jumpers to give
the green gun the red drive and the red gun the green drive. Sure the
pictures color will be all screwed up, but when the failure starts you will
know which it is, the tube or the circuits.

David

"Graeme Browne" <GraemeBrowne43@hotmail.com> wrote in message
news:b2edda6c.0401220219.a4e52ae@posting.google.com...
"David" <dkuhajda@locl.net.spam> wrote in message
news:<400f7e1a@news.greennet.net>...
Almost but not quite a sure way. Due to the internal design of the
tubes,
Toshiba's as well, the entire HV will quickly be present on the exposed
pins
of the tube and WILL arc out to anything close to it, including the
sensitive electronics on the pcb!!! Been there, done that, seen other
techs
in shop not listen to my warnings and destroy the main board as well,
argh!!!!!

To do this REQUIRES the use of a test crt socket that places all the
pins,
tied together is ok, of the tube through a resistor, usually 100K and a
couple of watts through a Neon lamp that also has a large resistor in
parallel with it,tied to crt dag ground. This will bleed off the rapid
hv
build up on the end of the tube. A dead short to dag
ground is a BAD idea on some tubes as well.

It does not really amaze me how many tubes are failing. The
manufactures
keep cutting corners to lower cost and eventually they hit a point where
an
unexpected large scale failures start to happen. It tends to go in
cycles
between manufactures across the board.

I'm not convinced a short on the cathode would show the behavior I saw
on the scope. The waveform was a 'sawtooth' (not sure of the amplitude
. I think it was 200V p-p) with pixel data imposed. As the red
fluctuated the amplitude of the pixel data fluctuated in sync. The
sawtooth remained stable. Surely if there was a short in the tube the
whole waveform would be effected ?

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:GsGPb.117816$I06.840132@attbi_s01...

"David" <dkuhajda@locl.net.spam> wrote in message
news:400f488e@news.greennet.net...
FYI it is the tube, 99.9% guaranteed.
Yes, a short in the red would vary the waveform on the red cathode.
Add
the
fact that the tv is also dealing with Philips version of AKB and you
really
get some odd effects.

Philips is well aware of the super high failure rate of the tubes
and
red
gun problems.

David


It really does amaze me how many of these are having this problem,
seems
these Philips sets are the next Zenith. A sure way to check would be
to
unplug the neck board *then* monitor the cathode voltage at the
socket.
Click to expand...
If the bad screen comes back I might just do that. The temptation is
to pull the neck card off and make the measurements but I don't like
the sound of HV arcing around the place (especially near me !) like
that.
But at the moment it seems to be working OK.
 
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