Re: Inverter or backlight

Re: "The screen flickers a few times then goes black but I can see the image with a flashlight"

Obviously, the problem is the backlight and not the actual LCD panel.

It is, in general, REALLY hard to know if a backlight problem is the inverter or the lamp. [In theory, you could stick a scope or a multimeter that could take up to 2,000 volts onto the output, but in most cases that is not practical or, really, safe).

It's easier (far easier) to replace the inverter, they are easier to get, easier to replace and, depending on the model and where you get parts, not much more expensive, if at all, so I usually go for the inverter first (also, in my case, I work almost exclusively on Toshiba laptops and I have a bunch of Toshiba inverters). I have even gone so far as to setup 2 laptops side by side and connect one laptop's screen to the other laptop's inverter (you have to remove the panel, or you can just swap the inverters). For test purposes, as long as the connectors are the same, the lamp should generally light if both the inverter and lamp are good. I would say that if the connectors (to the lamp) are the same, you can use a different inverter at least for testing; the lamp should light (it's possible that two inverters could be so different that a good lamp wouldn't light, but in every instance I have tried (even with inverters made for very different size panels, like 12" to 15", it has worked ... but, again, I'm only recommending this for a very quick go/no-go test).

Note that my comments that "as long as the connectors are the same" applies to the output (lamp, 2-wire connector) only. I don't think you can draw any conclusions about the input connectors, and that's a case where I would try a substitution only as a last resort where you can afford to lose the inverter, because the input cable from the laptop to the inverter (power and lamp control) could be VERY different, in a way that could destroy the inverter (or even the laptop). However, I did install a Toshiba 2805 inverter and 15" LCD panel into Toshiba 1400/2400 series laptops, and it worked great, both the panel itself and the entire backlight system. But that was a Toshiba/Toshiba substitution, albeit from models about 2 years apart.

I don't know an easy way to tell you make a stab at determining which is the problem. Replacing the CCFL tube is very iffy. I've done it successfully on a number of panels, but on other panels, I have ended up ruining either the panel or the lamp or both. The difficulty of lamp replacement really varies from quite easy to, as a practical matter, impossible. The best route is often an entire laptop from E-Bay, say one with a dead motherboard that doesn't power on at all, but that may have a good display AND inverter.


bobneworleans@xxxxxxxxx wrote:
On Mar 27, 10:51 pm, Barry Watzman <WatzmanNOS...@xxxxxxxxxx> wrote:
The replacement of lamps sometimes requires complete disassembly of the
panel optical stack. If you don't do this in a clean room (there are
different classes of clean rooms) or at a laminar flow workstation (the
equivalent of a low-class clean room), it is a near certainty that you
will get visible dust inside the optical stack which is a type of defect
in the re-lamped panel.

Barry,
Pardon my jumping into this discussion but I also have a similar
problem on
my Dell Inspiron 8200 and you seem to know what you're talking about.
The
screen flickers a few times then goes black but I can see the image
with a
flashlight. If I leave the laptop off for a few hours, the screen
will work fine
for a while. With the intensity at minimum, the screen will stay on
longer
before it goes dark. Does this almost certainly indicate a dying
inverter?

I read that Dell used several different types of LCD panels on this
model so
I took it apart and found that I have a Hitachi TX38D97VC1CAA. The
inverter
is a 67302700 PH-BLC103. PC Hub has one for about $20 plus shipping
from Singapore but there don't seem to be any of these parts available
here
at a reasonable price.

Can I substitute a Sharp (or some other) inverter for the one I
removed?

Any other advice other than cut my losses and replace the laptop? I
rather
fix it if feasible because I've taken care of it and it's in otherwise
excellent
condition.
Bob
.

Relevant Pages

  • Re: Dead/Dim screen on Dell Inspiron
    ... But service centers usually change everything; the LCD, lamp, and the inverter. ... It's either the lamp, inverter, or the wiring. ... I mostly use my laptop at one location anyway, so this is good for me. ...
    (comp.sys.laptops)
  • Re: Laptop LCD screen issue...
    ... Basically, there is a 98% chance that it's either the actual backlight lamp or the inverter that produced high voltage to power the tube. ... It is separately replaceable, but more than 90% of the shops you would take it to would repair the problem by replacing the entire LCD panel. ... A bare generic lamp is about $15, but does not have the wiring harness or connectors to install in the laptop. ...
    (comp.sys.laptops)
  • Re: help please..
    ... You either have a bad inverter or a bad lamp. ... The inverter is a separate board inside the LCD lid with the display panel. ... The lamp is a fluorescent tube that is physically located inside the LCD panel, but it's separately replaceable without replacing the entire panel. ...
    (comp.sys.laptops)
  • Re: Inverter or backlight
    ... If you don't do this in a clean room (there are ... will get visible dust inside the optical stack which is a type of defect ... in the re-lamped panel. ...
    (comp.sys.laptops)
  • Re: Inverter or backlight
    ... If you don't do this in a clean room (there are ... will get visible dust inside the optical stack which is a type of defect ... in the re-lamped panel. ...
    (comp.sys.laptops)
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