I have a Dell Latitude C840 which shows only a very dim image on its
15' LCD. The previous owner replaced the inverter and the ribbon cable
which he damaged while replacing the inverter. I can hook it up to an
external monitor and all is well, so not a video card issue. Is there
anything else I can check or do I need a new LCD? Any suggestions would
be very welcome. Thanks!

"ken10254" <kwolfdds******.com> wrote in message
news:1163000826.356338.148880@e3g2000cwe.googlegro ups.com
> I have a Dell Latitude C840 which shows only a very dim image on its
> 15' LCD. The previous owner replaced the inverter and the ribbon cable
> which he damaged while replacing the inverter. I can hook it up to an
> external monitor and all is well, so not a video card issue. Is there
> anything else I can check or do I need a new LCD? Any suggestions
> would be very welcome. Thanks!

If the inverter is truly good, it is most likely the florescent lamp
(they normally get dimmer and dimmer from hours of use). Unless he put
in the wrong inverter for that lamp.

--
Bill

BillW50 wrote:
> "ken10254" <kwolfdds******.com> wrote in message
> news:1163000826.356338.148880@e3g2000cwe.googlegro ups.com
> > I have a Dell Latitude C840 which shows only a very dim image on its
> > 15' LCD. The previous owner replaced the inverter and the ribbon cable
> > which he damaged while replacing the inverter. I can hook it up to an
> > external monitor and all is well, so not a video card issue. Is there
> > anything else I can check or do I need a new LCD? Any suggestions
> > would be very welcome. Thanks!
>
> If the inverter is truly good, it is most likely the florescent lamp
> (they normally get dimmer and dimmer from hours of use). Unless he put
> in the wrong inverter for that lamp.
>
> --
> Bill

Hi Bill;
I assume then that if the previous owner had left the LCD on all the
time, that the lamp is dead or dying. Does this necessitate a complete
new LCD? Can the lamp be replaced separately?
Thanks for your reply.

"ken10254" <kwolfdds******.com> wrote in message
news:1163043728.376769.257910@h54g2000cwb.googlegr oups.com
> BillW50 wrote:
>> "ken10254" <kwolfdds******.com> wrote in message
>> news:1163000826.356338.148880@e3g2000cwe.googlegro ups.com
>>> I have a Dell Latitude C840 which shows only a very dim image on its
>>> 15' LCD. The previous owner replaced the inverter and the ribbon
>>> cable which he damaged while replacing the inverter. I can hook it
>>> up to an external monitor and all is well, so not a video card
>>> issue. Is there anything else I can check or do I need a new LCD?
>>> Any suggestions would be very welcome. Thanks!
>>
>> If the inverter is truly good, it is most likely the florescent lamp
>> (they normally get dimmer and dimmer from hours of use). Unless he
>> put in the wrong inverter for that lamp.
>
> Hi Bill;
> I assume then that if the previous owner had left the LCD on all the
> time, that the lamp is dead or dying. Does this necessitate a complete
> new LCD? Can the lamp be replaced separately?
> Thanks for your reply.

Yes it is very possible that the lamp has many hours on it and the lamp
gets dimmer and dimmer with use. And it will eventually quit altogether.
And many lamps will quit just within 2 years if they are run 24/7. And
yes the lamp can be replaced separately as well. Although most repair
shops and manufactures will try to replace the LCD, inverter, and lamp
as one unit. Which costs $300 or more. While a lamp itself usually costs
around $30. Big difference, eh?

--
Bill

Lamps can be replaced separately from LCD panels, and economically in
most cases should be (a bare lamp is $10 to $35, a lamp assembly from
the laptop mfgr might be as much as $150, but a new LCD panel is $300 up).

The difficulty of the replacement varies from trivial to nearly
impossible (in which case, as a practical matter, you then do need to
replace the entire LCD assembly).

Note that the lamp assembly (e.g. lamp plus cable and connector) is a
product of the laptop mfgr, not the lcd panel mfgr. e.g. two identical
sharp LCD panels, one from a Toshiba laptop and one from a Compaq
laptop, might have different length lamp wires with different connectors
at the end, and thus be non-interchangeable.

Bare lamps are sold by Mouser electronics and Digi-Key, among others.
Very inexpensive ($12 to $20 is typical). While they have dozens of
lengths and diameters, they may or may not have an exact replacement for
any given laptop (and if they do, you still have to order by finding the
length and diameter ... in general, there is no cross reference from
laptop model to lamp part number, although one of the lamp mfgrs does
have such a reference on their site for a very few number of laptop models).

The wire from the lamp to the inverter is VERY special, it's silver
wire. When I do a bare lamp replacement, I cut off the wire from the
old lamp and reuse it on the new lamp (requires soldering). This also
resolves the connector issues.

You may or may not be able to get a complete "lamp assembly" (ready to
install with cable and connector) for your exact laptop model from the
laptop mfgr as a part. And the price may or may not be reasonable.


ken10254 wrote:
> BillW50 wrote:
>> "ken10254" <kwolfdds******.com> wrote in message
>> news:1163000826.356338.148880@e3g2000cwe.googlegro ups.com
>>> I have a Dell Latitude C840 which shows only a very dim image on its
>>> 15' LCD. The previous owner replaced the inverter and the ribbon cable
>>> which he damaged while replacing the inverter. I can hook it up to an
>>> external monitor and all is well, so not a video card issue. Is there
>>> anything else I can check or do I need a new LCD? Any suggestions
>>> would be very welcome. Thanks!
>> If the inverter is truly good, it is most likely the florescent lamp
>> (they normally get dimmer and dimmer from hours of use). Unless he put
>> in the wrong inverter for that lamp.
>>
>> --
>> Bill
>
> Hi Bill;
> I assume then that if the previous owner had left the LCD on all the
> time, that the lamp is dead or dying. Does this necessitate a complete
> new LCD? Can the lamp be replaced separately?
> Thanks for your reply.
>

Thanks guys;
I am looking at EBay for LCD panel replacements for this model. I see a
number of units which are complete with all the stuff as well as the
hinges, etc for $100-$150. What about doing that instead of fooling
with the lamp itself, which sounds pretty difficult?
Any thoughts?

Ken

Barry Watzman wrote:
> Lamps can be replaced separately from LCD panels, and economically in
> most cases should be (a bare lamp is $10 to $35, a lamp assembly from
> the laptop mfgr might be as much as $150, but a new LCD panel is $300 up).
>
> The difficulty of the replacement varies from trivial to nearly
> impossible (in which case, as a practical matter, you then do need to
> replace the entire LCD assembly).
>
> Note that the lamp assembly (e.g. lamp plus cable and connector) is a
> product of the laptop mfgr, not the lcd panel mfgr. e.g. two identical
> sharp LCD panels, one from a Toshiba laptop and one from a Compaq
> laptop, might have different length lamp wires with different connectors
> at the end, and thus be non-interchangeable.
>
> Bare lamps are sold by Mouser electronics and Digi-Key, among others.
> Very inexpensive ($12 to $20 is typical). While they have dozens of
> lengths and diameters, they may or may not have an exact replacement for
> any given laptop (and if they do, you still have to order by finding the
> length and diameter ... in general, there is no cross reference from
> laptop model to lamp part number, although one of the lamp mfgrs does
> have such a reference on their site for a very few number of laptop models).
>
> The wire from the lamp to the inverter is VERY special, it's silver
> wire. When I do a bare lamp replacement, I cut off the wire from the
> old lamp and reuse it on the new lamp (requires soldering). This also
> resolves the connector issues.
>
> You may or may not be able to get a complete "lamp assembly" (ready to
> install with cable and connector) for your exact laptop model from the
> laptop mfgr as a part. And the price may or may not be reasonable.
>
>
> ken10254 wrote:
> > BillW50 wrote:
> >> "ken10254" <kwolfdds******.com> wrote in message
> >> news:1163000826.356338.148880@e3g2000cwe.googlegro ups.com
> >>> I have a Dell Latitude C840 which shows only a very dim image on its
> >>> 15' LCD. The previous owner replaced the inverter and the ribbon cable
> >>> which he damaged while replacing the inverter. I can hook it up to an
> >>> external monitor and all is well, so not a video card issue. Is there
> >>> anything else I can check or do I need a new LCD? Any suggestions
> >>> would be very welcome. Thanks!
> >> If the inverter is truly good, it is most likely the florescent lamp
> >> (they normally get dimmer and dimmer from hours of use). Unless he put
> >> in the wrong inverter for that lamp.
> >>
> >> --
> >> Bill
> >
> > Hi Bill;
> > I assume then that if the previous owner had left the LCD on all the
> > time, that the lamp is dead or dying. Does this necessitate a complete
> > new LCD? Can the lamp be replaced separately?
> > Thanks for your reply.
> >

If you buy an entire lid, it may be easier to change the lid than the
LCD panel inside the lid.

Note that Dell uses different LCD panels in the same model of laptop
computer. For example, in the Inspiron E1505, there are four consumer
choices offered which are externally / functionally different. But, to
make matters worse, for EACH of those 4 choices, there may be multiple
panels used made by different LCD manufacturers (e.g. some may be built
with a Sharp LCD panel, some with a Hitachi panel, etc.). The problem
is that even within only one of the four externally differentiated LCD
panels, panels made by different manufacturers MAY NOT BE
INTERCHANGEABLE in a given laptop. This can make replacing an LCD panel
much more involved than most end users realize ... you may have to open
the lid and find out which exact panel that you have, and then make
certain that you get a replacement which is the exact same manufacturer
and part number. In some cases, it's not enough to simply get a
replacement panel from the same model of laptop. So keep those
considerations in mind. In fact, there was a thread on this board about
60 days ago from someone who did exactly that (got a replacement lid and
LCD panel from another Dell laptop of the same model number) and it
didn't work because the brand/model of LCD panel inside the lid was
actually different.


ken10254 wrote:
> Thanks guys;
> I am looking at EBay for LCD panel replacements for this model. I see a
> number of units which are complete with all the stuff as well as the
> hinges, etc for $100-$150. What about doing that instead of fooling
> with the lamp itself, which sounds pretty difficult?
> Any thoughts?
>
> Ken
>
> Barry Watzman wrote:
>> Lamps can be replaced separately from LCD panels, and economically in
>> most cases should be (a bare lamp is $10 to $35, a lamp assembly from
>> the laptop mfgr might be as much as $150, but a new LCD panel is $300 up).
>>
>> The difficulty of the replacement varies from trivial to nearly
>> impossible (in which case, as a practical matter, you then do need to
>> replace the entire LCD assembly).
>>
>> Note that the lamp assembly (e.g. lamp plus cable and connector) is a
>> product of the laptop mfgr, not the lcd panel mfgr. e.g. two identical
>> sharp LCD panels, one from a Toshiba laptop and one from a Compaq
>> laptop, might have different length lamp wires with different connectors
>> at the end, and thus be non-interchangeable.
>>
>> Bare lamps are sold by Mouser electronics and Digi-Key, among others.
>> Very inexpensive ($12 to $20 is typical). While they have dozens of
>> lengths and diameters, they may or may not have an exact replacement for
>> any given laptop (and if they do, you still have to order by finding the
>> length and diameter ... in general, there is no cross reference from
>> laptop model to lamp part number, although one of the lamp mfgrs does
>> have such a reference on their site for a very few number of laptop models).
>>
>> The wire from the lamp to the inverter is VERY special, it's silver
>> wire. When I do a bare lamp replacement, I cut off the wire from the
>> old lamp and reuse it on the new lamp (requires soldering). This also
>> resolves the connector issues.
>>
>> You may or may not be able to get a complete "lamp assembly" (ready to
>> install with cable and connector) for your exact laptop model from the
>> laptop mfgr as a part. And the price may or may not be reasonable.
>>
>>
>> ken10254 wrote:
>>> BillW50 wrote:
>>>> "ken10254" <kwolfdds******.com> wrote in message
>>>> news:1163000826.356338.148880@e3g2000cwe.googlegro ups.com
>>>>> I have a Dell Latitude C840 which shows only a very dim image on its
>>>>> 15' LCD. The previous owner replaced the inverter and the ribbon cable
>>>>> which he damaged while replacing the inverter. I can hook it up to an
>>>>> external monitor and all is well, so not a video card issue. Is there
>>>>> anything else I can check or do I need a new LCD? Any suggestions
>>>>> would be very welcome. Thanks!
>>>> If the inverter is truly good, it is most likely the florescent lamp
>>>> (they normally get dimmer and dimmer from hours of use). Unless he put
>>>> in the wrong inverter for that lamp.
>>>>
>>>> --
>>>> Bill
>>> Hi Bill;
>>> I assume then that if the previous owner had left the LCD on all the
>>> time, that the lamp is dead or dying. Does this necessitate a complete
>>> new LCD? Can the lamp be replaced separately?
>>> Thanks for your reply.
>>>
>