[ltp] 770X TFT

[Christopher Gavin]

> Yeah, they had not perfected white back in 1998.
> The newer panels have white, and some even "whiter
> than white."

Hmm. Ok...

> Maybe you should only look at it from an extreme
> angle?

Yeah I have started to look at it with the lid at a perfect right angle to the base. 
White still looks white from there ...

> There could be a lit cigarette inside, producing a
> small amount of yellowish smoke.  There probably
> isn't much air inside.  It should go out eventually.

I had a look but couldn't find one. 
 
> Seriouslie, mine is still perfect if
> dimmer than when new in October 1998.

Mine's very bright still .. but definately yellowed. 
Are there additional side lights for the brightness or does it all come from the one backlight?
Maybe running it on lowest brightness might help slow down lamp ageing if this is the case ...

> I did check and found an LCD mfr website that
> mentions the following in a tech report---the good
> news is that it suggests replacing the fluorescent
> lamp rather than the panel.  (I hope that's good
> news!)
> 
> Anecdotally, I have heard the backlight aging is
> sped up by operating at consistently high ambient
> temperatures.  Perhaps the prev owner lived in
> Death Valley.
> 
> Anyway, here is what Landmark Technology had to
> say.  This makes me wonder whether it is cheap /
> feasible to replace the backlight.  The real
> eye-opener is the 2300 hours figure:
> 
>     We noticed that all the backlights under test
>     became more yellow in color than the non-operated
>     control unit. As a result of this, we started to
>     monitor the backlight chromaticities (x, y) on all
>     the life tests conducted after summer of 1995.
>     The C033 test reveals a noticeable backlight
>     chromaticity shift toward yellow at as early as
>     2300 hours. This yellow color shift increases as
>     time goes by, becoming quite serious at about
>     5,000 hours and then the rate of increase slows
>     down.  The yellow shift in backlight color may
>     cause some concern in LCD applications where the
>     color fidelity is important. A major portion of
>     the yellow shift is caused by the yellowing (or
>     darkening) of the backlight materials. These
>     include diffusers, reflectors, adhesives and some
>     others.  By analyzing and isolating the bad
>     materials, Landmark has reduced this yellow color
>     shift problem significantly in the last three
>     years.

I'd say the problems are always the same - lack of parts. I have not found a single dealer/auctioneer with new parts to sell.
The spare panel I did find was quoted at 376 Uk Pounds. I only paid 200 for this unit ..

It is interesting tho. 2300 hrs is scary. Its also a bit of a shame its progressive. :Os
It basically means my 770X has a terminal illness. May as well sell it. Heh.

Chris.