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Science Forum Index » Electronics - Repair Forum » TV Image Not Filling Up Screen
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| vilja |
 Posted: Fri Jan 26, 2007 3:18 pm |
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Guest
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I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good. |
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| Leonard Caillouet |
| Posted: Fri Jan 26, 2007 4:04 pm |
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"vilja" <jaime.villela@gmail.com> wrote in message
news:1169839083.333035.177210@s48g2000cws.googlegroups.com...
Quote: I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good.
Someone told you wrong. You likely have the common optocoupler problem in
the power supply.
Leonard
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| vilja |
| Posted: Fri Jan 26, 2007 8:32 pm |
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Which optocoupler? Is there more than one?
On Jan 26, 2:04 pm, "Leonard Caillouet" <n...@noway.com> wrote:
Quote: "vilja" <jaime.vill...@gmail.com> wrote in messagenews:1169839083.333035.177210@s48g2000cws.googlegroups.com...
I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good.Someone told you wrong. You likely have the common optocoupler problem in
the power supply.
Leonard
--------------------------------------------------------------------------------
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| b |
| Posted: Fri Jan 26, 2007 10:04 pm |
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Guest
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On Jan 26, 8:18 pm, "vilja" <jaime.vill...@gmail.com> wrote:
Quote: I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good.
mains filer cap bad? seems like inadequete voltage on the b+. |
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| vilja |
| Posted: Sat Jan 27, 2007 2:04 pm |
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Guest
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Ok, but how do I know which filter cap?
On Jan 26, 8:04 pm, "b" <reverend_rog...@yahoo.com> wrote:
Quote: On Jan 26, 8:18 pm, "vilja" <jaime.vill...@gmail.com> wrote:
I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good.mains filer cap bad? seems like inadequete voltage on the b+. |
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| vilja |
| Posted: Sat Jan 27, 2007 3:27 pm |
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Guest
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I noticed something else: once the image fills the screen the B+
voltage is at 130 V but when I change channels it drops to about 110
V. What could that mean?
On Jan 27, 12:04 pm, "vilja" <jaime.vill...@gmail.com> wrote:
Quote: Ok, but how do I know which filter cap?
On Jan 26, 8:04 pm, "b" <reverend_rog...@yahoo.com> wrote:
On Jan 26, 8:18 pm, "vilja" <jaime.vill...@gmail.com> wrote:
I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good.mains filer cap bad? seems like inadequete voltage on the b+. |
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| b |
| Posted: Sat Jan 27, 2007 3:54 pm |
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Guest
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vilja ha escrito:
Quote: Ok, but how do I know which filter cap?
read it again, the *mains* filter cap.
judging by your responses I gather you are out of your depth here. For
your own safety I'd recommend having a tech look at this. You could
get injured, killed or mess things up beyond economical repair if you
go tinkering and guessing.
-B.. |
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| Franc Zabkar |
| Posted: Sun Jan 28, 2007 4:13 am |
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Guest
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On 27 Jan 2007 11:27:05 -0800, "vilja" <jaime.villela@gmail.com> put
finger to keyboard and composed:
Quote: I noticed something else: once the image fills the screen the B+
voltage is at 130 V but when I change channels it drops to about 110
V. What could that mean?
It's probably not the changing of channels that causes your B+ to
vary, it's most likely the change in image brightness, which in turn
results in a variation in the beam current. A higher beam current
means that the B+ droops under the extra load. I've seen these kinds
of faults caused by a bad filter cap on the B+ line, probably a 160V
type. I'd also check the mains filter cap as already suggested.
Quote: On Jan 27, 12:04 pm, "vilja" <jaime.vill...@gmail.com> wrote:
Ok, but how do I know which filter cap?
On Jan 26, 8:04 pm, "b" <reverend_rog...@yahoo.com> wrote:
On Jan 26, 8:18 pm, "vilja" <jaime.vill...@gmail.com> wrote:
I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good.mains filer cap bad? seems like inadequete voltage on the b+.
- Franc Zabkar
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Please remove one 'i' from my address when replying by email. |
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| vilja |
| Posted: Sun Jan 28, 2007 11:54 pm |
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Guest
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Thanks for the advice. I'll start with the caps on the B+ line then
move to the mains. My multimeter doesn't have a capacitance setting.
Is there some way I can check the caps with a scope or a regular
multimeter?
On Jan 28, 2:13 am, Franc Zabkar <fzab...@iinternode.on.net> wrote:
Quote: On 27 Jan 2007 11:27:05 -0800, "vilja" <jaime.vill...@gmail.com> put
finger to keyboard and composed:
I noticed something else: once the image fills the screen the B+
voltage is at 130 V but when I change channels it drops to about 110
V. What could that mean?It's probably not the changing of channels that causes your B+ to
vary, it's most likely the change in image brightness, which in turn
results in a variation in the beam current. A higher beam current
means that the B+ droops under the extra load. I've seen these kinds
of faults caused by a bad filter cap on the B+ line, probably a 160V
type. I'd also check the mains filter cap as already suggested.
On Jan 27, 12:04 pm, "vilja" <jaime.vill...@gmail.com> wrote:
Ok, but how do I know which filter cap?
On Jan 26, 8:04 pm, "b" <reverend_rog...@yahoo.com> wrote:
On Jan 26, 8:18 pm, "vilja" <jaime.vill...@gmail.com> wrote:
I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good.mains filer cap bad? seems like inadequete voltage on the b+.- Franc Zabkar
--
Please remove one 'i' from my address when replying by email. |
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| Leonard Caillouet |
| Posted: Mon Jan 29, 2007 2:57 pm |
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The location number in the sets that have this problem is 7412, IIRC.
Leonard
"vilja" <jaime.villela@gmail.com> wrote in message
news:1169857922.631120.181440@k78g2000cwa.googlegroups.com...
Quote: Which optocoupler? Is there more than one?
On Jan 26, 2:04 pm, "Leonard Caillouet" <n...@noway.com> wrote:
"vilja" <jaime.vill...@gmail.com> wrote in
messagenews:1169839083.333035.177210@s48g2000cws.googlegroups.com...
I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good.Someone told you wrong.
You likely have the common optocoupler problem in
the power supply.
Leonard
--------------------------------------------------------------------------------
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| vilja |
| Posted: Wed Jan 31, 2007 10:38 pm |
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Guest
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Thanks, Leonard. I was probing the pins on this device earlier and
something strange happened. When I touched my multimeter to pin 7 the
TV made a noise like it was about to shutdown. As if the circuit was
somehow being overdriven. I noticed that pin 7 is the base voltage
and on my circuit is connected to ground through a 500k resistor. I
thought it odd since pin 5 is also connected to ground through a
resistor and nothing happened when I checked the voltage there. Could
it be that my multimeter was doing something screwy or is it a sure
sign that this is the bad part?
On Jan 29, 12:57 pm, "Leonard Caillouet" <n...@noway.com> wrote:
Quote: The location number in the sets that have this problem is 7412, IIRC.
Leonard
"vilja" <jaime.vill...@gmail.com> wrote in message
news:1169857922.631120.181440@k78g2000cwa.googlegroups.com...
Which optocoupler? Is there more than one?
On Jan 26, 2:04 pm, "Leonard Caillouet" <n...@noway.com> wrote:
"vilja" <jaime.vill...@gmail.com> wrote in
messagenews:1169839083.333035.177210@s48g2000cws.googlegroups.com...
I have a Philips 9P5511 large screen TV that shows an image smaller
than the screen. It first stared with a jittery image. Now when I
turn it on the image is shaped like a sofa cushion (rounded sides but
corners still visible). If I leave it on for a few minutes the image
stretches to fill the screen vertically but it is still jittery.
Someone told me the Vertical Deflection IC was bad so I changed
it--wrong. What else could it be? I've examined the circuit boards
for signs of damage but everything looks good.Someone told you wrong.
You likely have the common optocoupler problem in
the power supply.
Leonard
--------------------------------------------------------------------------------
I am using the free version of SPAMfighter for private users.
It has removed 31098 spam emails to date.
Paying users do not have this message in their emails.
Try SPAMfighter for free now!
--------------------------------------------------------------------------------
I am using the free version of SPAMfighter for private users.
It has removed 31507 spam emails to date.
Paying users do not have this message in their emails.
Try SPAMfighter for free now! |
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| Franc Zabkar |
| Posted: Thu Feb 01, 2007 4:11 am |
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Guest
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On 28 Jan 2007 19:54:47 -0800, "vilja" <jaime.villela@gmail.com> put
finger to keyboard and composed:
Quote: Thanks for the advice. I'll start with the caps on the B+ line then
move to the mains. My multimeter doesn't have a capacitance setting.
Is there some way I can check the caps with a scope or a regular
multimeter?
If your cap is bad, I believe you should see a lot of high frequency
ripple on your scope. I generally use an ESR meter. In any case a
replacement cap is cheap so I would change it just for good measure.
- Franc Zabkar
--
Please remove one 'i' from my address when replying by email. |
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| vilja |
| Posted: Thu Feb 01, 2007 8:19 pm |
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Guest
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Changed the cap and still not good. I'll try to the opto coupler
next.
Thanks.
On Feb 1, 2:11 am, Franc Zabkar <fzab...@iinternode.on.net> wrote:
Quote: On 28 Jan 2007 19:54:47 -0800, "vilja" <jaime.vill...@gmail.com> put
finger to keyboard and composed:
Thanks for the advice. I'll start with the caps on the B+ line then
move to the mains. My multimeter doesn't have a capacitance setting.
Is there some way I can check the caps with a scope or a regular
multimeter?
If your cap is bad, I believe you should see a lot of high frequency
ripple on your scope. I generally use an ESR meter. In any case a
replacement cap is cheap so I would change it just for good measure.
- Franc Zabkar
--
Please remove one 'i' from my address when replying by email. |
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| vilja |
| Posted: Mon Feb 12, 2007 9:23 pm |
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Guest
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It worked!!!! I changed the optocoupler and it's working now. I
never would have guessed it. Thanks for everyone's help. It's great
to have my TV back :-)
On Feb 1, 6:19 pm, "vilja" <jaime.vill...@gmail.com> wrote:
Quote: Changed the cap and still not good. I'll try to the opto coupler
next.
Thanks.
On Feb 1, 2:11 am, Franc Zabkar <fzab...@iinternode.on.net> wrote:
On 28 Jan 2007 19:54:47 -0800, "vilja" <jaime.vill...@gmail.com> put
finger to keyboard and composed:
Thanks for the advice. I'll start with the caps on the B+ line then
move to the mains. My multimeter doesn't have a capacitance setting.
Is there some way I can check the caps with a scope or a regular
multimeter?
If your cap is bad, I believe you should see a lot of high frequency
ripple on your scope. I generally use an ESR meter. In any case a
replacement cap is cheap so I would change it just for good measure.
- Franc Zabkar
--
Please remove one 'i' from my address when replying by email. |
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| bass0r |
| Posted: Wed Feb 14, 2007 1:20 pm |
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