[PLUG] Screens, sizes, LED backlight replacement

Keith Lofstrom keithl at kl-ic.com
Mon Jul 26 21:39:56 UTC 2021


Chuck Hast replaced his Samsung 1920x1080 monitor because it
was old and the fluorescent backlight was dim and hard to
replace.  Now he struggles to configure a 3440x1440 monitor.

While I'm confident he will eventually succeed, he will end
up with a 2.39 wide screen rather than a 1.78 wide screen
(or a VERY TALL screen after a physical and software rotation).

These newer runt screens are even more useless for those of us
who use our computers to write page formatted text intended for
publication.  Or work with two different computers at once.

I use two screens side by side - with one (soon two) KVM
switches to switch back and forth between the workhorse
computer and a candidate upgrade computer.  Right now, I
use two ancient Planar 1280x1024 monitors tilted sideways,
though I would love to upgrade those to perhaps 1600x1200
or 1920x1440. 

But the CCFL backlights on those screens are growing dim,
like Chuck's Samsung.  Ditto for some of the ancient 4x3
Thinkpad laptops that I still use.
T
Fortunately, there are aftermarket LED backlight replacements
for old CCFL backlights, for example:

https://www.ebay.com/itm/324150061494?hash=item4b78d969b6:g:h5kAAOSwhQlep-N8

( or search eBay for "LED backlight replacement" )

I haven't tried one of these kits yet, and that particular
replacement appears to use big wide LEDs rather than a string
of small narrow LEDs.  That may result in uneven illumination
and vertical banding in the display.  Fortunately, I have a
stack of old Thinkpads to experiment with, and those strips
are very inexpensive.

When this pandemic is finally quelled (children vaccinated, 
anti-vaxxers in quarantine camps), it will be fun to plan a
CCFL-to-LED backlight replacement party.  The Freegeek
conference room where we held the Linux clinic is not ideal;
electronic technician work benches with solder stations and
test equipment would be better.  Perhaps a local electronics
company can host us for that, or perhaps an electronics lab
at PCC or PSU, in return for some software geekery. 

When we get good at this, we can also rejuvenate screens for
local schools, so they can spend more money on teachers and
less on hardware replacement.

Keith

PS:  monitors are sold by diagonal size, while production
cost scales to square inches (as a fraction of a huge sheet
of production glass).

Long ago, LCD glass was difficult to make and production
yield was low; as quality improved, the screens grew bigger
and prices soared.  But few customers had deskspace for a
40 inch diagonal ( 32 inch wide, 24 inch high)  monitor.

So an evil marketing genius re-purposed that "40 inch" glass
to make TWO 24 inch wide, 16 inch high screens ... "29 inch"
diagonal after rounding up.   Then called them "WIDE"
screens, rather than vertically-halved or "RUNT" screens.

The most profitable screen would be 120 inches wide and one
inch high ... "HYPER WIDE".  I hope I don't live long enough
to endure that.

LCD screens are now made on gigantic sheets of glass, 10 by
12 feet and larger, then sliced into individual screens.
Most of the production costs scale to the number of sheets
made, not sheet size;  per-screen unit cost will get smaller
and smaller. 

It may be concerning that US tax laws favor making these
giant sheets in China rather than in the US, but these
huge robotic screen factories employ few people and make
lots of pollution.  I prefer making the screens in China,
the flash memory in Korea, and the CPUs in Hillsboro.

The downside is that Chuck must puzzle through screen
manuals written in Chinglish, but the upside is that our
Linux operating systems are written in English.  WIN!

-- 
Keith Lofstrom          keithl at keithl.com



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