On 12/08/2019 17:00, firstname.lastname@example.org wrote:
The last one I threw away had a failed backlight, so not much use for this!
I did strip it down and found that it was failure of the LEDs and not
the power supply. Replacements were too expensive to bother trying to
In the video it is noted that it is the diffuser and fresnel lens
in the screen is more use than a backlight (he replaces a backlight
that is inconvenient to power with a fairly generic LED strip).
On 12/08/2019 22:30, email@example.com wrote:
Not all screens are edge lit though. Many of the ones I have
seen/repaired have a backlight consisting of strips of LEDs mounted
on long thin PCBs, that point at the back of the screen panel, and are
arranged in a number of rows down the screen. These screens have lots of
diffusion layers, but not always a fresnel one.
 Individual LEDs failing, often stopping the backlight PSU from
starting, leading to no backlight. You can identify the failed strip by
powering it up from a few cascaded PP3s. Sometimes the failed LED looks
obvious due to heat damage around it. Desoldering the chip may restore
operation, although IME, once they have started failing, others will
soon follow. The strips are usually pricey enough to make repair non
economic if you need to replace more than one.
Aren't there screens which have LEDs lighting a square of pixels so the
black areas of the screen don't have to be backlit at all? And dimly lit
areas have partly lit LEDs and the TFT elements adjusted to suit?
Does anyone remember the Seiko portable black and whit tvs. They had a kind
of clam shell design with a mirror in one half and an lcd with a window
behind it. The idea being you or could sit in the park and look into the
mirror and the daylight was the backlight. It was fine for black and white
of course and the batteries lasted for ages. The did sell a self powered
back light for it, but it was heavy and ate batteries.
This newsgroup posting comes to you directly from...
What sad individual would sit in the park watching TV?
Even at this point in my existence, where scantily clad females have
lost a lot of their appeal, I still wouldn,t watch TV when out.
Saol fada agus breac-shláinte chugat.
Unless of course you are a Brexit voting moron or
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