Screen Tablet malarky => Monitors => Topic started by: thatcomicsguy on June 08, 2015, 04:55:58 AM

Title: Converting Cintiq21UX from CCFL to LED.
Post by: thatcomicsguy on June 08, 2015, 04:55:58 AM
I've got this old eBay Cintiq 21UX. It's a bit beat up with a thumb-sized bruise dead-center, but it's a good work size and the digitizer is still top-notch. I've even gotten used to seeing 'through' the bruise when I do use it.

Anyway, I've recently been adjusting my studio to run off 12 Volt solar panels and batteries.

Those old Cintiqs are serious power hogs, so I thought it might be an interesting project to see if I can't convert it to LED.

To this end I've ordered these LED strips:

When they arrive, I'll post pics of my experiment.

Title: Re: Converting Cintiq21UX from CCFL to LED.
Post by: Aerendraca on June 08, 2015, 06:53:37 AM
What a great little kit, and cheap too! I look forward to seeing how you get on with this.

Title: Re: Converting Cintiq21UX from CCFL to LED.
Post by: thatcomicsguy on June 27, 2015, 06:04:03 AM
Well, my LED strips are, according to the tracking info, only a couple of days away from arriving.

However, in doing some research into the kind of power savings I could expect by switching from CCFL in the Cintiq to using the DIY LED strips, I was a little surprised to learn that it probably won't be a whole lot.

Here's an example...,2930-5.html

The venerable Cintiq 21UX draws approximately 54 watts when in full use at full brightness.  However, when compared to similarly built monitors of the day which run instead on LED lighting, the power savings were negligible.  It seems that the internal electronics driving the LCD and other hardware is where the wattage is used up, and that a good CCFL bulb and an LED strip draw about the same energy.

Enter modern monitor electronics...

New market competitor, UGEE, with their UG-2150 (a Cintiq alternative) offers a 1080p 21.5" modern screen, and for whatever reason, (advances in basic video electronics perhaps?), manages to draw only a modest 18.5 watts.

Now, I was hoping that by converting to LED that I could drop the Cintiq down to around the same level seen in the UGEE, but according to the tests run on similar old screen tech, it seems that I may be disappointed; that the hungry components aren't necessarily the old-style CCFL bulbs, but rather the rest of the electronics.

To help answer this question, I ordered one of these...

I'll do some before-and-after testing to see what is what.

And mind you, none of this is terribly vital; my solar studio is really just a nerdist's playground for tinkering.  But notwithstanding that, when it comes to running gear off big deep cycle 12 volt batteries, the difference between 54 watts and 18.5 translates into some huge real-world effects.

Here's some of the math...

Estimate about 30 watts drawn (on average) by the laptop I'm using, plus around 10-15 watts for lighting and incidentals, (like external hard drives and such), plus 54 watts for the Cintiq, and we're looking at around 100 watts for the whole studio system.

On a two-battery set-up (each rated for 100 Amp hours), you run the following formula: Watt hours = Voltage * Amp hours, or 12 * 200 = 2400 watt hours.

You can only drain batteries to the half-way mark (otherwise you damage them), so divide that again by 2, and you get 1200 usable watt hours.

With a system drawing 100 watts, we see that we can run it for 12 hours before having to shut down.  Not bad.  That's a full day's work plus some, but if this is your daily work station and you are relying entirely on the Sun for energy, if you string a couple of cloudy days into your week, the system will very quickly demonstrate the upper limits of its utility.  One can see that carving a few watts off the load here and there can make a big difference.

For instance, if we pull the Cintiq out of the equation and replace it with that 18.5 watt UGEE, the whole system will instead be drawing around 63 watts.  This means we're getting 19 hours on a full charge.  A difference of a full 7 hours!

You can perhaps begin to see why I'm interested in curbing the Cintiq's appetite.

Now.., just to play a bit with the math here...  if I were truly living out in the woods, or if the power grid was down for an extended time, (and the world was not ending and still had a need for cartoonists), I could make the same solar system really earn its keep.  -I could unhook most of the systems from my little studio grid, LED lights and extra hard drives and my little USB external monitor, and fire up instead my old Tecra M4 tablet PC, a computer and Penabled drawing screen in one, which does it all for only around 35 watts.  -So now that 1200 watt battery array can provide 34 hours of up-time between charges.  Not bad!

But in any case, it will still be interesting to know what pulling the four CCFL bulbs and their inverters from the Cintiq and replacing them with a pair of modern LED strips will do for its power appetite.  If it makes a significant difference, then that's good!  -I mean, if you can get a Cintiq running at a comparable rate, then why not make your off-the-grid studio all the more comfy?

Stay tuned!

Title: Re: Converting Cintiq21UX from CCFL to LED.
Post by: thatcomicsguy on June 30, 2015, 08:33:47 PM
Well, my LED strips arrived.

They're pretty cool.  Very bright and they run directly off 12 DC.  -And they come with a controller designed to be integrated into the LCD system, allowing for dimming and such.

However.., I'm not sure it's worth installing them.  Each of the two strips pulls 23.5 Watts, for a total of 47 Watts, which may even raise the Cintiq's total power draw.

I might pull apart my 21" test monitor to see if using just one strip would be sufficient.

(I bought another using the same chassis as the Cintiq 21UX to try to swap out the LCD to deal with the bruise on the Cintiq, but despite the perfect fit of all the parts, the electronics were not the same and the result was the same jitter issue typical with DIY builds, so I scrapped the project).

I'm not feeling optimistic about it, but I won't know until I try.

Title: Re: Converting Cintiq21UX from CCFL to LED.
Post by: thatcomicsguy on July 11, 2015, 03:16:34 AM
Well.., I pulled apart my NEC Cintiq duplicate monitor and mucked around with it and the LED strips.

Interesting note: The LED strip I had was about a centimeter too long, and all I had to do was snap off two of the LEDs at one end.  All the remaining lights continued to work as normal.  Handy.

Anyway, I carefully removed the CCFL bulb arrangement along one edge of the screen.

Another interesting note: There are three bulbs, each running the full length of both screen edges, (top and bottom).  There are six total connectors on the LED driver board.  I'm not sure if the controller board turns them on/off in sequence as you raise and lower the screen brightness, or if all six are permanently on and the multi-bulb arrangement is simply to provide even lighting.  I didn't power it up without putting everything back together first as the LCD connector was attached to a shielding unit which covered up the bulb driver.  So I don't know...

Anyway, I unplugged all the CCFLs and wired up the LED strip to a 12 volt battery, and powered it up.

The lighting was uneven, bright at the bottom (where I put the strip) and fading out toward the top.  Also, the lighting was uneven along the bottom edge, due to the directional nature of the LEDs.  While this *could* be sufficient for using the Cintiq, it would be irritating and very noticeable.  Not a good solution.

Two strips would have worked, I think, with better placement of the strips, but the power saving advantages would have been lost.

I did try another approach.  I pulled the connectors for some of the CCFL bulbs to see if I could run the screen on only 2 or 4 bulbs rather than all six, (I don't use the screen at full brightness anyway), but in a couple of trials with different configurations, the screen did not light up at all, so that was a failure as well.

So once again, I put the NEC screen back together as it originally was, with the CCFL bulbs back in place, and tucked the whole setup back in my parts closet.

No joy.

Sorry, but I didn't bother to take any photographs.  -I figured if I went ahead and tried it all out on the actual Cintiq that I'd document things more carefully, but never got to that point.

Title: Re: Converting Cintiq21UX from CCFL to LED.
Post by: Aerendraca on July 13, 2015, 06:46:42 AM
I think one of the problems you experienced with reducing the number of ccfls is entirely down to a feedback circuit which is used as a safety feature. Each ccfl draws a certain amount of current (which by the way isn't very much on account of them running at a high voltage), that current draw is then compared against that of the feedback circuit, if the current drops below the threshold of the feedback circuit the power source is shut down. This is done so that the user knows that something is wrong with the screen, since as you might imagine, if you lost one ccfl bulb of your six you might not notice, and should one of the ccfls break (smash) there is a chance that the open ends of the bulb could make the chassis live at voltages upwards from about 700V.

Also, were you trying to replace the 6 ccfls with a single strip on one edge? For screens that use ccfls/leds on two edges the way the diffuser assembly works is slightly different with each side responsible for illuminating 50% of the screen. A single led strip would only have a light guide to cover half the screen at best.

This must be a pretty thick slab of acrylic making up the backlight assembly if each side has 3ccfls, however it must also have a pretty good gamut across the board with that much light being spread throughout. What panel is it by the way? (apologies if already mentioned, I must have missed it)

Title: Re: Converting Cintiq21UX from CCFL to LED.
Post by: thatcomicsguy on July 15, 2015, 05:36:58 AM
The panel came from an NEC Display MultiSync LCD2180UX-BK LCD Monitor LCD 21" 1600x1200.

The acrylic diffuser was at least a half inch thick!  Looked like a sci-fi prop.

And yes, I'd agree with your assessment.  It was all just sort of a follow-up series of (pathetic) experiments upon learning that the LED strips pulled a good deal more power than I'd thought they would.  I probably should have done more research before purchasing them.

If I wanted to get really fancy, it might be possible to completely re-engineer the display so that I provided my own power to the CCFLs and arrange them using a more power-conscious method, but it seems like a lot of trouble for a small return.

Better just to get another battery for my solar set-up and live with it.

As a note of interest somewhat beside the point...

I picked up a so called, "Kill-A-Watt" meter which measures the energy usage of electric devices, and measured the actual draw on all my gear.

The Cintiq pulls 54 Watts in full use.

By comparison.., that dual screen DIY build of mine using re-purposed 14" screens from old Tecra M4s only pulls 18 Watts.  That's using a pair of NJY Touch controllers.

I'm beginning to question the value of this 21" Cintiq.

The laptop everything is plugged into (A Dell E6410) pulls between 35 - 50 Watts depending on the load.  (That's including a couple of external drives and a USB 10" monitor plugged in).  So, running that with the Cintiq is around 100 Watts.  With a 3 battery set-up, I can run that configuration at max capacity for 18 hours between charges.

Using the DIY build with the Dell, I'd get around 26.5 hours.  With a single screen turned on, that goes up to 30.5 hours.

My backpack Toshiba Tecra M4 tablet PC pulls a surprising (to me anyway) 50 Watts during regular use.  (Photoshop, etc.)

So just using just the old Tecra on those three batteries would give me 36 hours of studio up-time between charges.