Sign in with
Sign up | Sign in
Your question

Is there a way to determine if I need a new LCD or just th..

Last response: in Laptops & Notebooks
Share
May 2, 2005 9:51:08 PM

Archived from groups: comp.sys.laptops (More info?)

Hi,

I have a TP600X and when I first turn on the laptop, the screen turned
on for maybe few seconds, then flickers for couple seconds, then it is
off. I can use external monitor to use the laptop, and when I swap
between LCD and external monitor, the LCD sometimes will come on for
couple seconds, then it's off again. Is this a typical inverter
problem? or should I just look for a LCD assembly. As the laptop is
getting old I'm trying to save money and get only what I needed. Would
really appreciate someone have similar problem shares their
experiences with me.

Thanks.

More about : determine lcd

May 2, 2005 9:51:09 PM

Archived from groups: comp.sys.laptops (More info?)

Don wrote:
> Hi,
>
> I have a TP600X and when I first turn on the laptop, the screen turned
> on for maybe few seconds, then flickers for couple seconds, then it is
> off. I can use external monitor to use the laptop, and when I swap
> between LCD and external monitor, the LCD sometimes will come on for
> couple seconds, then it's off again. Is this a typical inverter
> problem? or should I just look for a LCD assembly. As the laptop is
> getting old I'm trying to save money and get only what I needed. Would
> really appreciate someone have similar problem shares their
> experiences with me.
>
> Thanks.

First, be careful. There's a lot of voltage at the inverter output.
You can learn something by probing the transformer output, but you have
to use a high voltage probe. DO NOT try this with a standard scope
probe as you can fry the probe...ask me how I know ;-(.
You can waive a probe around outside the case. Compare what you see
to a good laptop. You should be able to tell of the inverter is not
running.

There's often a high voltage cap in series between the secondary and the
lamp. I've seen these go open. Check fine out of the circuit, but
replacing the cap fixed it. Once, on a weak lamp, I paralleled up two
of the caps to make it come back to life.
Doesn't hurt to clean the circuit board around the transformer and
output. Make sure it's DRY before you power it back up.

Transformers tend to heat up and short turns.

I've had good luck just hooking up another lcd backlight to the inverter
to see if it's good. But this is risky because of the differences
between models.
You could do more harm than good.

I've tried to hook a lamp up to a curve tracer without success.
1500V should be enough to fire it off, but it didn't.?????

Fry's carries some lamps. It's hit or miss, but worth a look if you
live close to one.

If you try to replace the lamp with a generic one, you have to
be very careful. They're incredibly easy to break. Each time I did it,
I had to file on the plastic to get it to fit without binding/breaking.
mike

--
Return address is VALID but some sites block emails
with links. Delete this sig when replying.
..
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Wanted 12" LCD for Compaq Armada 7770MT.
Bunch of stuff For Sale and Wanted at the link below.
MAKE THE OBVIOUS CHANGES TO THE LINK
ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/
Anonymous
a b D Laptop
May 2, 2005 10:09:54 PM

Archived from groups: comp.sys.laptops (More info?)

It's probably the inverter, but if not the inverter, then most likely
the lamp(s). Although these are inside the LCD panel itself, they can
usually be replaced without replacing the whole panel, and at a
resonable cost (the lamps themselves are usually $10 to $30 each, some
panels use two of them, others only one). Replacement ranges from very
easy to very difficult and in a few cases impossible. (Digikey has a
reasonable selection of generic replacment lamps if you know the
diameter and length). However, the problem is far more likely to be the
inverter, which is a bit more expensive, equally difficult to get
(althogh maybe not for a Thinkpad), and much, much easier to replace.

For a Thinkpad and many Toshiba models, you can find used but perfectly
fine working inverters on E-Bay from $5 to $25 (new ones would often be
$30 to $80). The more common the laptop, the easier it is to find an
inverter for it.

You can tell that the panel itself is ok if you can see a VERY FAINT
image of the screen. This can be very difficult to see, and you may
want to get a bright flashlight and shine it at the screen, or even hold
it right up against the screen (in either case, try both straight and at
an angle). However, even lacking that, from your description, it's a
problem with the backlight and not the actual panel proper.

Be careful working in this area, the inverter puts out very high
voltages (sometimes over 1,000 volts) that can be lethal.

Don wrote:

> Hi,
>
> I have a TP600X and when I first turn on the laptop, the screen turned
> on for maybe few seconds, then flickers for couple seconds, then it is
> off. I can use external monitor to use the laptop, and when I swap
> between LCD and external monitor, the LCD sometimes will come on for
> couple seconds, then it's off again. Is this a typical inverter
> problem? or should I just look for a LCD assembly. As the laptop is
> getting old I'm trying to save money and get only what I needed. Would
> really appreciate someone have similar problem shares their
> experiences with me.
>
> Thanks.
Related resources
May 2, 2005 10:27:42 PM

Archived from groups: comp.sys.laptops (More info?)

I can actually see the complete display every time I point a a bright
led flash light against the screen. I guess it is not the problem with
the LCD panel then ( which is good news for me as the panel is much
more expansive ). I can find a used inverter on ebay for less than $10
so I will give it a try then. When you say the inverter can give out
over 1000 volts how should I replace the inverter? Is unplugging the
AC power and remove the battery good enough then??

Btw, thanks for the quick response.


Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:

>It's probably the inverter, but if not the inverter, then most likely
>the lamp(s). Although these are inside the LCD panel itself, they can
>usually be replaced without replacing the whole panel, and at a
>resonable cost (the lamps themselves are usually $10 to $30 each, some
>panels use two of them, others only one). Replacement ranges from very
>easy to very difficult and in a few cases impossible. (Digikey has a
>reasonable selection of generic replacment lamps if you know the
>diameter and length). However, the problem is far more likely to be the
>inverter, which is a bit more expensive, equally difficult to get
>(althogh maybe not for a Thinkpad), and much, much easier to replace.
>
>For a Thinkpad and many Toshiba models, you can find used but perfectly
>fine working inverters on E-Bay from $5 to $25 (new ones would often be
>$30 to $80). The more common the laptop, the easier it is to find an
>inverter for it.
>
>You can tell that the panel itself is ok if you can see a VERY FAINT
>image of the screen. This can be very difficult to see, and you may
>want to get a bright flashlight and shine it at the screen, or even hold
>it right up against the screen (in either case, try both straight and at
>an angle). However, even lacking that, from your description, it's a
>problem with the backlight and not the actual panel proper.
>
>Be careful working in this area, the inverter puts out very high
>voltages (sometimes over 1,000 volts) that can be lethal.
>
>Don wrote:
>
>> Hi,
>>
>> I have a TP600X and when I first turn on the laptop, the screen turned
>> on for maybe few seconds, then flickers for couple seconds, then it is
>> off. I can use external monitor to use the laptop, and when I swap
>> between LCD and external monitor, the LCD sometimes will come on for
>> couple seconds, then it's off again. Is this a typical inverter
>> problem? or should I just look for a LCD assembly. As the laptop is
>> getting old I'm trying to save money and get only what I needed. Would
>> really appreciate someone have similar problem shares their
>> experiences with me.
>>
>> Thanks.
Anonymous
a b D Laptop
May 2, 2005 10:27:43 PM

Archived from groups: comp.sys.laptops (More info?)

Don wrote:
> I can actually see the complete display every time I point a a bright
> led flash light against the screen. I guess it is not the problem with
> the LCD panel then ( which is good news for me as the panel is much
> more expansive ). I can find a used inverter on ebay for less than $10
> so I will give it a try then. When you say the inverter can give out
> over 1000 volts how should I replace the inverter? Is unplugging the
> AC power and remove the battery good enough then??
>
> Btw, thanks for the quick response.
>
>
> Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
>
>> It's probably the inverter, but if not the inverter, then most likely
>> the lamp(s). Although these are inside the LCD panel itself, they
>> can usually be replaced without replacing the whole panel, and at a
>> resonable cost (the lamps themselves are usually $10 to $30 each,
>> some panels use two of them, others only one). Replacement ranges
>> from very easy to very difficult and in a few cases impossible.
>> (Digikey has a reasonable selection of generic replacment lamps if
>> you know the diameter and length). However, the problem is far more
>> likely to be the inverter, which is a bit more expensive, equally
>> difficult to get (althogh maybe not for a Thinkpad), and much, much
>> easier to replace.
>>
>> For a Thinkpad and many Toshiba models, you can find used but
>> perfectly fine working inverters on E-Bay from $5 to $25 (new ones
>> would often be $30 to $80). The more common the laptop, the easier
>> it is to find an inverter for it.
>>
>> You can tell that the panel itself is ok if you can see a VERY FAINT
>> image of the screen. This can be very difficult to see, and you may
>> want to get a bright flashlight and shine it at the screen, or even
>> hold it right up against the screen (in either case, try both
>> straight and at an angle). However, even lacking that, from your
>> description, it's a problem with the backlight and not the actual
>> panel proper.
>>
>> Be careful working in this area, the inverter puts out very high
>> voltages (sometimes over 1,000 volts) that can be lethal.
>>
>> Don wrote:
>>
>>> Hi,
>>>
>>> I have a TP600X and when I first turn on the laptop, the screen
>>> turned on for maybe few seconds, then flickers for couple seconds,
>>> then it is off. I can use external monitor to use the laptop, and
>>> when I swap between LCD and external monitor, the LCD sometimes
>>> will come on for couple seconds, then it's off again. Is this a
>>> typical inverter problem? or should I just look for a LCD assembly.
>>> As the laptop is getting old I'm trying to save money and get only
>>> what I needed. Would really appreciate someone have similar problem
>>> shares their experiences with me.
>>>
>>> Thanks.

If there is a replacement inverter from the manufacturer, that will be
the replacement of choice. I've purchased several inverters on eBay and
with the exception on one, the balance were near the end of their useful
lives since they were parted from failed laptops. Inverters deteriorate
not only from the degrading effects of producing high voltage, but also
(perhaps mainly) from heat generation and placement in the bezel where
there virtually no cooling.

Q
Anonymous
a b D Laptop
May 3, 2005 4:22:23 AM

Archived from groups: comp.sys.laptops (More info?)

Yes, if you unplug it and remove the main battery, that's fine. Unlike
some other devices (such as a CRT tube), there is no significant storage
of power in those circuits once all sources of power have been removed.


Don wrote:

> I can actually see the complete display every time I point a a bright
> led flash light against the screen. I guess it is not the problem with
> the LCD panel then ( which is good news for me as the panel is much
> more expansive ). I can find a used inverter on ebay for less than $10
> so I will give it a try then. When you say the inverter can give out
> over 1000 volts how should I replace the inverter? Is unplugging the
> AC power and remove the battery good enough then??
>
> Btw, thanks for the quick response.
>
>
> Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
>
>
>>It's probably the inverter, but if not the inverter, then most likely
>>the lamp(s). Although these are inside the LCD panel itself, they can
>>usually be replaced without replacing the whole panel, and at a
>>resonable cost (the lamps themselves are usually $10 to $30 each, some
>>panels use two of them, others only one). Replacement ranges from very
>>easy to very difficult and in a few cases impossible. (Digikey has a
>>reasonable selection of generic replacment lamps if you know the
>>diameter and length). However, the problem is far more likely to be the
>>inverter, which is a bit more expensive, equally difficult to get
>>(althogh maybe not for a Thinkpad), and much, much easier to replace.
>>
>>For a Thinkpad and many Toshiba models, you can find used but perfectly
>>fine working inverters on E-Bay from $5 to $25 (new ones would often be
>>$30 to $80). The more common the laptop, the easier it is to find an
>>inverter for it.
>>
>>You can tell that the panel itself is ok if you can see a VERY FAINT
>>image of the screen. This can be very difficult to see, and you may
>>want to get a bright flashlight and shine it at the screen, or even hold
>>it right up against the screen (in either case, try both straight and at
>>an angle). However, even lacking that, from your description, it's a
>>problem with the backlight and not the actual panel proper.
>>
>>Be careful working in this area, the inverter puts out very high
>>voltages (sometimes over 1,000 volts) that can be lethal.
>>
>>Don wrote:
>>
>>
>>>Hi,
>>>
>>>I have a TP600X and when I first turn on the laptop, the screen turned
>>>on for maybe few seconds, then flickers for couple seconds, then it is
>>>off. I can use external monitor to use the laptop, and when I swap
>>>between LCD and external monitor, the LCD sometimes will come on for
>>>couple seconds, then it's off again. Is this a typical inverter
>>>problem? or should I just look for a LCD assembly. As the laptop is
>>>getting old I'm trying to save money and get only what I needed. Would
>>>really appreciate someone have similar problem shares their
>>>experiences with me.
>>>
>>>Thanks.
>
>
Anonymous
a b D Laptop
May 3, 2005 4:23:50 AM

Archived from groups: comp.sys.laptops (More info?)

Inverters are solid state devices and usually do not deteriorate until
or unless they fail completely.


Quaoar wrote:

> Don wrote:
>
>>I can actually see the complete display every time I point a a bright
>>led flash light against the screen. I guess it is not the problem with
>>the LCD panel then ( which is good news for me as the panel is much
>>more expansive ). I can find a used inverter on ebay for less than $10
>>so I will give it a try then. When you say the inverter can give out
>>over 1000 volts how should I replace the inverter? Is unplugging the
>>AC power and remove the battery good enough then??
>>
>>Btw, thanks for the quick response.
>>
>>
>>Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
>>
>>
>>>It's probably the inverter, but if not the inverter, then most likely
>>>the lamp(s). Although these are inside the LCD panel itself, they
>>>can usually be replaced without replacing the whole panel, and at a
>>>resonable cost (the lamps themselves are usually $10 to $30 each,
>>>some panels use two of them, others only one). Replacement ranges
>>>from very easy to very difficult and in a few cases impossible.
>>>(Digikey has a reasonable selection of generic replacment lamps if
>>>you know the diameter and length). However, the problem is far more
>>>likely to be the inverter, which is a bit more expensive, equally
>>>difficult to get (althogh maybe not for a Thinkpad), and much, much
>>>easier to replace.
>>>
>>>For a Thinkpad and many Toshiba models, you can find used but
>>>perfectly fine working inverters on E-Bay from $5 to $25 (new ones
>>>would often be $30 to $80). The more common the laptop, the easier
>>>it is to find an inverter for it.
>>>
>>>You can tell that the panel itself is ok if you can see a VERY FAINT
>>>image of the screen. This can be very difficult to see, and you may
>>>want to get a bright flashlight and shine it at the screen, or even
>>>hold it right up against the screen (in either case, try both
>>>straight and at an angle). However, even lacking that, from your
>>>description, it's a problem with the backlight and not the actual
>>>panel proper.
>>>
>>>Be careful working in this area, the inverter puts out very high
>>>voltages (sometimes over 1,000 volts) that can be lethal.
>>>
>>>Don wrote:
>>>
>>>
>>>>Hi,
>>>>
>>>>I have a TP600X and when I first turn on the laptop, the screen
>>>>turned on for maybe few seconds, then flickers for couple seconds,
>>>>then it is off. I can use external monitor to use the laptop, and
>>>>when I swap between LCD and external monitor, the LCD sometimes
>>>>will come on for couple seconds, then it's off again. Is this a
>>>>typical inverter problem? or should I just look for a LCD assembly.
>>>>As the laptop is getting old I'm trying to save money and get only
>>>>what I needed. Would really appreciate someone have similar problem
>>>>shares their experiences with me.
>>>>
>>>>Thanks.
>
>
> If there is a replacement inverter from the manufacturer, that will be
> the replacement of choice. I've purchased several inverters on eBay and
> with the exception on one, the balance were near the end of their useful
> lives since they were parted from failed laptops. Inverters deteriorate
> not only from the degrading effects of producing high voltage, but also
> (perhaps mainly) from heat generation and placement in the bezel where
> there virtually no cooling.
>
> Q
>
>
May 3, 2005 4:58:14 AM

Archived from groups: comp.sys.laptops (More info?)

So are you suggesting it is not the inverter that cause the problem??

Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:

>Inverters are solid state devices and usually do not deteriorate until
>or unless they fail completely.
>
>
>Quaoar wrote:
>
>> Don wrote:
>>
>>>I can actually see the complete display every time I point a a bright
>>>led flash light against the screen. I guess it is not the problem with
>>>the LCD panel then ( which is good news for me as the panel is much
>>>more expansive ). I can find a used inverter on ebay for less than $10
>>>so I will give it a try then. When you say the inverter can give out
>>>over 1000 volts how should I replace the inverter? Is unplugging the
>>>AC power and remove the battery good enough then??
>>>
>>>Btw, thanks for the quick response.
>>>
>>>
>>>Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
>>>
>>>
>>>>It's probably the inverter, but if not the inverter, then most likely
>>>>the lamp(s). Although these are inside the LCD panel itself, they
>>>>can usually be replaced without replacing the whole panel, and at a
>>>>resonable cost (the lamps themselves are usually $10 to $30 each,
>>>>some panels use two of them, others only one). Replacement ranges
>>>>from very easy to very difficult and in a few cases impossible.
>>>>(Digikey has a reasonable selection of generic replacment lamps if
>>>>you know the diameter and length). However, the problem is far more
>>>>likely to be the inverter, which is a bit more expensive, equally
>>>>difficult to get (althogh maybe not for a Thinkpad), and much, much
>>>>easier to replace.
>>>>
>>>>For a Thinkpad and many Toshiba models, you can find used but
>>>>perfectly fine working inverters on E-Bay from $5 to $25 (new ones
>>>>would often be $30 to $80). The more common the laptop, the easier
>>>>it is to find an inverter for it.
>>>>
>>>>You can tell that the panel itself is ok if you can see a VERY FAINT
>>>>image of the screen. This can be very difficult to see, and you may
>>>>want to get a bright flashlight and shine it at the screen, or even
>>>>hold it right up against the screen (in either case, try both
>>>>straight and at an angle). However, even lacking that, from your
>>>>description, it's a problem with the backlight and not the actual
>>>>panel proper.
>>>>
>>>>Be careful working in this area, the inverter puts out very high
>>>>voltages (sometimes over 1,000 volts) that can be lethal.
>>>>
>>>>Don wrote:
>>>>
>>>>
>>>>>Hi,
>>>>>
>>>>>I have a TP600X and when I first turn on the laptop, the screen
>>>>>turned on for maybe few seconds, then flickers for couple seconds,
>>>>>then it is off. I can use external monitor to use the laptop, and
>>>>>when I swap between LCD and external monitor, the LCD sometimes
>>>>>will come on for couple seconds, then it's off again. Is this a
>>>>>typical inverter problem? or should I just look for a LCD assembly.
>>>>>As the laptop is getting old I'm trying to save money and get only
>>>>>what I needed. Would really appreciate someone have similar problem
>>>>>shares their experiences with me.
>>>>>
>>>>>Thanks.
>>
>>
>> If there is a replacement inverter from the manufacturer, that will be
>> the replacement of choice. I've purchased several inverters on eBay and
>> with the exception on one, the balance were near the end of their useful
>> lives since they were parted from failed laptops. Inverters deteriorate
>> not only from the degrading effects of producing high voltage, but also
>> (perhaps mainly) from heat generation and placement in the bezel where
>> there virtually no cooling.
>>
>> Q
>>
>>
May 3, 2005 4:59:35 AM

Archived from groups: comp.sys.laptops (More info?)

Good to know. Will give it a try once the ebay inverter arrives.

Thanks again for your help ..

Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:

>Yes, if you unplug it and remove the main battery, that's fine. Unlike
>some other devices (such as a CRT tube), there is no significant storage
>of power in those circuits once all sources of power have been removed.
>
>
>Don wrote:
>
>> I can actually see the complete display every time I point a a bright
>> led flash light against the screen. I guess it is not the problem with
>> the LCD panel then ( which is good news for me as the panel is much
>> more expansive ). I can find a used inverter on ebay for less than $10
>> so I will give it a try then. When you say the inverter can give out
>> over 1000 volts how should I replace the inverter? Is unplugging the
>> AC power and remove the battery good enough then??
>>
>> Btw, thanks for the quick response.
>>
>>
>> Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
>>
>>
>>>It's probably the inverter, but if not the inverter, then most likely
>>>the lamp(s). Although these are inside the LCD panel itself, they can
>>>usually be replaced without replacing the whole panel, and at a
>>>resonable cost (the lamps themselves are usually $10 to $30 each, some
>>>panels use two of them, others only one). Replacement ranges from very
>>>easy to very difficult and in a few cases impossible. (Digikey has a
>>>reasonable selection of generic replacment lamps if you know the
>>>diameter and length). However, the problem is far more likely to be the
>>>inverter, which is a bit more expensive, equally difficult to get
>>>(althogh maybe not for a Thinkpad), and much, much easier to replace.
>>>
>>>For a Thinkpad and many Toshiba models, you can find used but perfectly
>>>fine working inverters on E-Bay from $5 to $25 (new ones would often be
>>>$30 to $80). The more common the laptop, the easier it is to find an
>>>inverter for it.
>>>
>>>You can tell that the panel itself is ok if you can see a VERY FAINT
>>>image of the screen. This can be very difficult to see, and you may
>>>want to get a bright flashlight and shine it at the screen, or even hold
>>>it right up against the screen (in either case, try both straight and at
>>>an angle). However, even lacking that, from your description, it's a
>>>problem with the backlight and not the actual panel proper.
>>>
>>>Be careful working in this area, the inverter puts out very high
>>>voltages (sometimes over 1,000 volts) that can be lethal.
>>>
>>>Don wrote:
>>>
>>>
>>>>Hi,
>>>>
>>>>I have a TP600X and when I first turn on the laptop, the screen turned
>>>>on for maybe few seconds, then flickers for couple seconds, then it is
>>>>off. I can use external monitor to use the laptop, and when I swap
>>>>between LCD and external monitor, the LCD sometimes will come on for
>>>>couple seconds, then it's off again. Is this a typical inverter
>>>>problem? or should I just look for a LCD assembly. As the laptop is
>>>>getting old I'm trying to save money and get only what I needed. Would
>>>>really appreciate someone have similar problem shares their
>>>>experiences with me.
>>>>
>>>>Thanks.
>>
>>
Anonymous
a b D Laptop
May 3, 2005 8:04:33 AM

Archived from groups: comp.sys.laptops (More info?)

No, In this case I am suggesting that the inverter has a failure mode
that causes it to fail a few seconds after starting almost every time.
My point was that, in general, inverters do not get gradually "weaker"
(read: dimmer backlight) over time. They work until they fail. But
some failure modes are intermittent or are involved with "starting" (in
particular because this type of lamp takes a higher voltage to "start"
than to continue running). In this case, I think that's the failure mode.

But the problem could be in the lamps themselves, although I think that
is less likely.



Don wrote:
> So are you suggesting it is not the inverter that cause the problem??
>
> Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
>
>
>>Inverters are solid state devices and usually do not deteriorate until
>>or unless they fail completely.
>>
>>
>>Quaoar wrote:
>>
>>
>>>Don wrote:
>>>
>>>
>>>>I can actually see the complete display every time I point a a bright
>>>>led flash light against the screen. I guess it is not the problem with
>>>>the LCD panel then ( which is good news for me as the panel is much
>>>>more expansive ). I can find a used inverter on ebay for less than $10
>>>>so I will give it a try then. When you say the inverter can give out
>>>>over 1000 volts how should I replace the inverter? Is unplugging the
>>>>AC power and remove the battery good enough then??
>>>>
>>>>Btw, thanks for the quick response.
>>>>
>>>>
>>>>Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
>>>>
>>>>
>>>>
>>>>>It's probably the inverter, but if not the inverter, then most likely
>>>>>the lamp(s). Although these are inside the LCD panel itself, they
>>>>>can usually be replaced without replacing the whole panel, and at a
>>>>>resonable cost (the lamps themselves are usually $10 to $30 each,
>>>>>some panels use two of them, others only one). Replacement ranges
>>>>
>>>>>from very easy to very difficult and in a few cases impossible.
>>>>
>>>>>(Digikey has a reasonable selection of generic replacment lamps if
>>>>>you know the diameter and length). However, the problem is far more
>>>>>likely to be the inverter, which is a bit more expensive, equally
>>>>>difficult to get (althogh maybe not for a Thinkpad), and much, much
>>>>>easier to replace.
>>>>>
>>>>>For a Thinkpad and many Toshiba models, you can find used but
>>>>>perfectly fine working inverters on E-Bay from $5 to $25 (new ones
>>>>>would often be $30 to $80). The more common the laptop, the easier
>>>>>it is to find an inverter for it.
>>>>>
>>>>>You can tell that the panel itself is ok if you can see a VERY FAINT
>>>>>image of the screen. This can be very difficult to see, and you may
>>>>>want to get a bright flashlight and shine it at the screen, or even
>>>>>hold it right up against the screen (in either case, try both
>>>>>straight and at an angle). However, even lacking that, from your
>>>>>description, it's a problem with the backlight and not the actual
>>>>>panel proper.
>>>>>
>>>>>Be careful working in this area, the inverter puts out very high
>>>>>voltages (sometimes over 1,000 volts) that can be lethal.
>>>>>
>>>>>Don wrote:
>>>>>
>>>>>
>>>>>
>>>>>>Hi,
>>>>>>
>>>>>>I have a TP600X and when I first turn on the laptop, the screen
>>>>>>turned on for maybe few seconds, then flickers for couple seconds,
>>>>>>then it is off. I can use external monitor to use the laptop, and
>>>>>>when I swap between LCD and external monitor, the LCD sometimes
>>>>>>will come on for couple seconds, then it's off again. Is this a
>>>>>>typical inverter problem? or should I just look for a LCD assembly.
>>>>>>As the laptop is getting old I'm trying to save money and get only
>>>>>>what I needed. Would really appreciate someone have similar problem
>>>>>>shares their experiences with me.
>>>>>>
>>>>>>Thanks.
>>>
>>>
>>>If there is a replacement inverter from the manufacturer, that will be
>>>the replacement of choice. I've purchased several inverters on eBay and
>>>with the exception on one, the balance were near the end of their useful
>>>lives since they were parted from failed laptops. Inverters deteriorate
>>>not only from the degrading effects of producing high voltage, but also
>>>(perhaps mainly) from heat generation and placement in the bezel where
>>>there virtually no cooling.
>>>
>>>Q
>>>
>>>
>
>
May 3, 2005 9:47:49 PM

Archived from groups: comp.sys.laptops (More info?)

Thanks again for the explanation Barry.


Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:

>No, In this case I am suggesting that the inverter has a failure mode
>that causes it to fail a few seconds after starting almost every time.
>My point was that, in general, inverters do not get gradually "weaker"
>(read: dimmer backlight) over time. They work until they fail. But
>some failure modes are intermittent or are involved with "starting" (in
>particular because this type of lamp takes a higher voltage to "start"
>than to continue running). In this case, I think that's the failure mode.
>
>But the problem could be in the lamps themselves, although I think that
>is less likely.
>
>
>
>Don wrote:
>> So are you suggesting it is not the inverter that cause the problem??
>>
>> Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
>>
>>
>>>Inverters are solid state devices and usually do not deteriorate until
>>>or unless they fail completely.
>>>
>>>
>>>Quaoar wrote:
>>>
>>>
>>>>Don wrote:
>>>>
>>>>
>>>>>I can actually see the complete display every time I point a a bright
>>>>>led flash light against the screen. I guess it is not the problem with
>>>>>the LCD panel then ( which is good news for me as the panel is much
>>>>>more expansive ). I can find a used inverter on ebay for less than $10
>>>>>so I will give it a try then. When you say the inverter can give out
>>>>>over 1000 volts how should I replace the inverter? Is unplugging the
>>>>>AC power and remove the battery good enough then??
>>>>>
>>>>>Btw, thanks for the quick response.
>>>>>
>>>>>
>>>>>Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
>>>>>
>>>>>
>>>>>
>>>>>>It's probably the inverter, but if not the inverter, then most likely
>>>>>>the lamp(s). Although these are inside the LCD panel itself, they
>>>>>>can usually be replaced without replacing the whole panel, and at a
>>>>>>resonable cost (the lamps themselves are usually $10 to $30 each,
>>>>>>some panels use two of them, others only one). Replacement ranges
>>>>>
>>>>>>from very easy to very difficult and in a few cases impossible.
>>>>>
>>>>>>(Digikey has a reasonable selection of generic replacment lamps if
>>>>>>you know the diameter and length). However, the problem is far more
>>>>>>likely to be the inverter, which is a bit more expensive, equally
>>>>>>difficult to get (althogh maybe not for a Thinkpad), and much, much
>>>>>>easier to replace.
>>>>>>
>>>>>>For a Thinkpad and many Toshiba models, you can find used but
>>>>>>perfectly fine working inverters on E-Bay from $5 to $25 (new ones
>>>>>>would often be $30 to $80). The more common the laptop, the easier
>>>>>>it is to find an inverter for it.
>>>>>>
>>>>>>You can tell that the panel itself is ok if you can see a VERY FAINT
>>>>>>image of the screen. This can be very difficult to see, and you may
>>>>>>want to get a bright flashlight and shine it at the screen, or even
>>>>>>hold it right up against the screen (in either case, try both
>>>>>>straight and at an angle). However, even lacking that, from your
>>>>>>description, it's a problem with the backlight and not the actual
>>>>>>panel proper.
>>>>>>
>>>>>>Be careful working in this area, the inverter puts out very high
>>>>>>voltages (sometimes over 1,000 volts) that can be lethal.
>>>>>>
>>>>>>Don wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>Hi,
>>>>>>>
>>>>>>>I have a TP600X and when I first turn on the laptop, the screen
>>>>>>>turned on for maybe few seconds, then flickers for couple seconds,
>>>>>>>then it is off. I can use external monitor to use the laptop, and
>>>>>>>when I swap between LCD and external monitor, the LCD sometimes
>>>>>>>will come on for couple seconds, then it's off again. Is this a
>>>>>>>typical inverter problem? or should I just look for a LCD assembly.
>>>>>>>As the laptop is getting old I'm trying to save money and get only
>>>>>>>what I needed. Would really appreciate someone have similar problem
>>>>>>>shares their experiences with me.
>>>>>>>
>>>>>>>Thanks.
>>>>
>>>>
>>>>If there is a replacement inverter from the manufacturer, that will be
>>>>the replacement of choice. I've purchased several inverters on eBay and
>>>>with the exception on one, the balance were near the end of their useful
>>>>lives since they were parted from failed laptops. Inverters deteriorate
>>>>not only from the degrading effects of producing high voltage, but also
>>>>(perhaps mainly) from heat generation and placement in the bezel where
>>>>there virtually no cooling.
>>>>
>>>>Q
>>>>
>>>>
>>
>>
!