topic Re: Reusing old LCD screens in Tech Help - Software/Hardware etc

Reusing old LCD screens

picbits — Sat, 12 Jul 2014 20:02:13 GMT

Now I'm a great believer in waste not want not and often grab broken screens / televisions off Freegle or Freecycle, repair them and use them until they die again.
Often the panels are fine but the driving electronics or inverters have failed. Most don't have HDMI or DVI sockets so I had a play with some cheap Chinese LVDS drivers.
I've had some good results with both the MT6820 LVDS (VGA only) and this morning managed to get a LA.MV29.P HDMI / VGA / Composite / TV board reflashed with new firmware and driving my test 17" LCD Panel
Cost are £3 delivered for the MT controller or £7.50 for the LA.MV controller
£3 delivered for a 4 tube inverter
£2 delivered for the LVDS cable (ironically comes with the £3 MT controller free !)
£2 delivered for a 5 switch keypad for the above (again comes with the MT controller)
You need a 12v supply for the inverter and a 5v supply for the MT controller
The LA controller has a 12v to 5v regulator built in so you only need to feed it 12 at around 3amps
12v 3A PSUs can be had for around a fiver for for £15 ish you can build a complete controller which will drive most of the bare LCD panels commonly found in televisions or monitors. If the screen dies, grab a new reclaimed screen, set the controller up for it and off you go again.
I thought I'd got a bargain a couple of weeks ago when I bagged 10 brand new Samsung 17" panels for £70 delivered but there were 7 working used panels, 1 dead Samsung panel and two different make panels (all used with defects) so next weeks task is to raise a dispute for those
Good if you have a bit of spare time and want to play around with wires and stuff

Re: Reusing old LCD screens

VileReynard — Sat, 12 Jul 2014 20:58:30 GMT

What is the cause of those peculiar image artifacts in that last picture?

Re: Reusing old LCD screens

picbits — Sat, 12 Jul 2014 21:23:13 GMT

The screen that I was using used 8 pair LVDS but the board was set to 4 pair LVDS if I remember rightly.

Re: Reusing old LCD screens

Thunderclap — Sun, 13 Jul 2014 08:22:11 GMT

Kudos. That's very green
btw LVDS connectors are on some Nano-ITX boards - ideal for those who want to turn their old Dell monitor into an i-Mac!
So have you ever tried replacing the tube with a strip of white LED's - and saying adios to the nasty high tension inverter? I've seen that done using a flexible LED strip. The LED's needed to be physically small in order to efficiently shine down the edge of the plastic diffuser screen. There was a crude 555 PWM driver to give brightness control. The only issue was a slight alteration in the gamut.as day-white LEDs have a different spectra to florescent tubes. Even more green.

Re: Reusing old LCD screens

picbits — Sun, 13 Jul 2014 09:01:41 GMT

I've investigated the LED backlighting retrofitting and there are some kits out there already on the market. If you look hard enough you can get a couple of strips for around £20 delivered which would be good for a 19" screen.
At £3 for an inverter it is a fair bit cheaper at the moment but when I bag myself a reel of superbright white LED's ............. watch this space