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June 25, 2017, 04:46:13 AM *
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 1 
 on: June 24, 2017, 09:46:32 AM 
Started by DaBotz - Last post by DaBotz
Thanks again, Ertew. I see no converter on the power board, though I still have to un-mount it so it could well be on the other side(for the moment, I have no access to my usual working table, so I will have to shelf this project for a little while)...

More than a bit of a Bummer, for me.

---

Yes, I already supposed that I had to build some Analog to PWM converter.

I found a schema, on-line, that should do the trick and, with a small adaptation, being able to provide a tunable frequency

[ Attachment: You are not allowed to view attachments ]

(just using a variable resistor for R4 should allow a certain degree of tune, but I'll look it better when I have a bit of time to install a SPICE and play... if I remember my electrics well, that RC time constant is way too low, off by a couple of magnitudes).



 2 
 on: June 23, 2017, 09:30:44 PM 
Started by DaBotz - Last post by Ertew
I looked at monitor documentation once again. Schematics are for main PCB. This board have analog RGB input only.
There are also second PCB called power board and contain input connectors. If DVI->VGA converter exist, there must be chip for that job. If You cannot found converter chip (min. 20 pins) on power board, this monitor have only DVI-A input.

I'm 100% sure that dimming are realized by PWM output. No one use DAC for analog output. There are only two options: PWM or analog via PWM + resistor + capacitor.
Look at PDF, page 38, top left corner. There are a lot of signals. Somewhere in the middle You can found DIM-ADJ (7) signal. It's connected to two resistors and capacitor.
IMHO You should use DIY analog->PWM converter. Yes, You can get PWM signal by removing capacitor or by connecting directly to chip (left side od R61 ? ). But there are second problem, PWM frequency. LED driver have limited frequency capacity (often above 100hz, rarely above 1khz). On the other hand monitor chip can easily produce PWM signal with range 4khz - 45khz, depend on selected options.

 3 
 on: June 23, 2017, 07:17:27 PM 
Started by DaBotz - Last post by DaBotz
Checked the line...

Output is

 0.1 V   with brightness at 100%

 5 V with brighness at 0%

I fear that it is not a PWM , but a direct analog output, as the LED board doesn't seem to respond much to the brightness control.

(but it heats up less the LED, so, maybe it's just that my etes do not see the difference)

If it is an analog, I suppose I could wip up an analog-PWM converter with a capacitor, a resistor, a diode and the usual double op-ampli chip... I should really need some kind of signal analyzer.   

 4 
 on: June 22, 2017, 11:50:44 PM 
Started by DaBotz - Last post by DaBotz
Thanks, Ertew... bummer for the analog-only input.  Why on Earth did they decide to have a DVI connector there, instead of a classic D-Sub, escapes me.

I will check page 40, thanks.

... oh, it i the line with the blue cable (the only one different, all the others are grey)

I feel more than a bit dumb.

Being able to dim the brightness will be very nice, as at full power it is almost too bright and heats up quite a bit.


 5 
 on: June 22, 2017, 06:30:00 PM 
Started by DaBotz - Last post by Ertew
DVI input:
I checked schematic and cannot found digital input. Looks like main electronic board have only VGA input. I'm not sure whet to say about DVI->VGA converter but I'm sure that it doesn't exist on schematic.

Inverter voltages:
Most CCFL drivers works from 3.3V to 12V. If higher supply voltage is essential, controller may be powered from "enable" line or from main input through resistor and zener (simple voltage stabilizer). First solution is common in laptop designs. In Your case I'm sure that 24V goes only to CCFL transformer and power transistors. 5V goes to driver chip.

Inverter pinout:
look at page 40 (of 41). Inverter need single 5V line. Second one are PWM  Cool

 6 
 on: June 22, 2017, 02:56:08 PM 
Started by DaBotz - Last post by DaBotz
A little time ago, I ceded to a temptation - an Intuos 2 12x12 USB, for 1euro (+10 of shipping fees).

The guy selling it wasn't sure it worked, it lacked a button (not really... just that odd cover that is in place of a Reset button used in some iteration of the serial connection tablets) and had no pen, but the light went up when attached to the usb, and the computer "saw" it.

Being educated in the ways of Bongofishism, I gambled on it having nothing more than marks and scruffs.

For a while, it has sat around in my drawing place, waiting for the future.

Then, a month or so, I was struck by yet another attack of Cintiquism, and went on ebay for a cheap 15" with external power brick - possibly with DVI connection.

The few I saw asked too much money, for my taste (this would be my sixth build, after all), but I finally saw an IBM 9493-ag1 for 25 Euros, shipping included.

[ Attachment: You are not allowed to view attachments ]

I checked its service manual, found on-line ( https://www.manualslib.com/manual/963035/Ibm-9493-Aw1.html ) , and saw that it had an internal (hidden below a cover) DVI input socket, that went to the outside through a DVI to D-Sub (VGA) cable.

It also had replaceable CCFL lamps (which were likely in need to be replaced, as this is a business monitor and must have logged in 8 hours a day since the day it was bought).

Alas, I didn't peruse the manual long enough, or I would have seen that the LCD is a LG LM151X2-F2MN,  attached to the monitor module through a Hirose DF9-41p connector, and a whole twelve cm or so  (say, 5" in imperial units) of cable.

I so hoped it would be a 30 lines LVDS on a 1mm pitch FFC (like in the three LG monitors that I have opened).   

[ Attachment: You are not allowed to view attachments ]

That is going to bite my ass...

Also, it is a 6 bit LCD (whoops - this wasn't going to be a "main battle Cintiq", anyway, just another "fast selection" screen, if it is not too messy, jitterwise - also, I hope that IBM did a good job with dithering, in the monitor firmware).

It arrived in a couple of days, and I immediately realized that the CCFL were - if not almost dead - very well ripe.

It took a minute or so to reach full brightness, on switch-on, and it wasn't much bright, anyway

I decided to invest some more 9 $ to buy one of those "Upgrade to LED" kits, before opening up the screen.

I am sorry that I did not take pictures of the disassembly of the monitor (extremely well put together... it has more screws and RF cage than those present in all the monitors I dismounted to date), but it is actually detailed in the service manual (so, it would be a a bit redundant).

When I reached finally inside the monitor, I saw the damn "Hirose on a short leash" connection, then saw that the back metal plate of the LCD was simply attached to a white plastic frame, and could be removed without opening the LCD panel (Good).

The CCFL are in pretty sturdy assemblies with a steel beam-channel containing them, and slide in-out of the panel pretty easily - so I could replace them with the LED bars, in a matter of an hour or so, ONCE I understood which cables are what.

In fact, instead of the 4 cables I expected, the inverter assembly - a Samsung LG1501 - was connected to the monitor's module with a ten pin connector, and ten individual lines (note: even if on my monitor, a permanent marker line marked the monitor module side, it doesn't matter if one's inverts the head or tail of the ten-lines, as they are flipped in the travel from one side to another)

Initially, I was perplexed, however a couple of continuity tests at monitor unplugged from the power grid and some final corroboration with it switched on and off, gave this pretty simple pin-out

     +5V       What the hell are these for?
     +5V

     0V - GND
     0V - GND
    
     +4.9 V (on) / 0V (off )  -  enable , or enable+d¡m? I failed to see any difference in the value, though, when I dimmed down the brightness

     -0.1  V (Huh??)

     0V - GND
     0V - GND
 
     24V
     24V

Notable miss: which is the damn dim line? No idea.

I removed the LCD backplate; probably, sanding/filing down the plastic sprockets that hold it in place could lower its height 1-1.5 mm.

However, I saw something that just a couple of years ago would have been a snafu, for me - it has two PCBs, one folded back for the column driver, a more components heavy one for the row driver, connected by a 20 lines, 0.5mm pitch flexible PCB.

[ Attachment: You are not allowed to view attachments ]

I bought and extender, from an Italian seller, and some 15cm (note: it is a bit tight; it would be better some ten cm, or so, more) of the correspondent FFC.

Once I got the extender and the FFC, I folded out the main PCB, and extended the lines of one CCFL, to see if this mod works.


It does.

[ Attachment: You are not allowed to view attachments ]

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(Note that, at full brightness, Photoshop retouch wasn't needed to see around the screen)

Yesterday I received the LED kit, and I proceeded to replace the CCFL.

[ Attachment: You are not allowed to view attachments ]
(Retouched with Photoshop; even this way, the "aura" of the screen, with the LED, is well visible.)

It works as expected, at least twice as bright as before, but at the moment I have no dimming whatsoever.

Someone has any idea / suggestion?  
  

 7 
 on: June 21, 2017, 12:51:32 PM 
Started by axel9546 - Last post by DaBotz
Note... I checked the TCon heats up, on my builds too.

I wouldn't be too worried about it, apart that it becomes a mess to work on them when the weather is warm.


Pens and screen borders is often a bit of a mess... typically, one must accept that the pen will "go away" in the area near the horizontal or vertical border of the tablet.

The best you can do is to calibrate it so that the pen is reasonably accurate in the widest possible area... not being able to go on the borders complicates a tiny bit the calibration.

Check the Simtiq planner   ( https://www.dropbox.com/s/676vr2qyxeuhab2/simtiq_planner.html?dl=1 ) to have an idea of the initial values.

Given the data of your screen, you should reduce the projection on the screen some 60 pixeels for each side (so, left, 60, right 1860) and see how it goes  from there.

(in your case, you have to change the screen projection, not the tablet area, to tune the X axis )




 8 
 on: June 20, 2017, 08:22:09 AM 
Started by axel9546 - Last post by axel9546
For the LCD, it depends on the kind of modifications you had to do to it to let the pens signal go through.

If you had to eliminate stuff that could act as an heat-sink, it's actual temperature is probably higher than the original (and optimal), so adding an heat-sink for the led strip could be a good idea.

If it is hot the TCon-Board... are you sure the Converter board is supplying the right voltage to the panel?

On the side of the converter board, I  am a bit more dubious... but, then again, I never checked the temperature of the controller boards in my builds (of the 5, three were actual desktop monitors, so compatibility among the various parts was a given).

I never noticed them to get "very hot" - using  thermometer to get a temperature could give some hard facts on which guess - , though.

Okay i Will try for anche heatsink.Anyway in stuck to calibration. Tried 3h or calibration and Pen at the center of the LCD its okay, but when i move to the right or left, not follow well the Pen

 9 
 on: June 20, 2017, 12:22:03 AM 
Started by axel9546 - Last post by DaBotz
For the LCD, it depends on the kind of modifications you had to do to it to let the pens signal go through.

If you had to eliminate stuff that could act as an heat-sink, it's actual temperature is probably higher than the original (and optimal), so adding an heat-sink for the led strip could be a good idea.

If it is hot the TCon-Board... are you sure the Converter board is supplying the right voltage to the panel?

On the side of the converter board, I  am a bit more dubious... but, then again, I never checked the temperature of the controller boards in my builds (of the 5, three were actual desktop monitors, so compatibility among the various parts was a given).

I never noticed them to get "very hot" - using  thermometer to get a temperature could give some hard facts on which guess - , though.

 10 
 on: June 19, 2017, 11:28:06 PM 
Started by axel9546 - Last post by axel9546
A 15.6" is a 16:9 LCD which is wider thasn the active area, yet shorter than it... it is a particularly complex situation because you need to calibrate the Table AND the proyection on the screen.

My biggest builds are in the same situation, so this may help you...

https://www.youtube.com/watch?v=rRXBb_hafAY

To build the thing, you can try to place it so that cursor and pen coincide at the centre, then work up on one dimension (for example, height, by reducing the tablet active area), then the other (width, you'll have to reduce the projection on screen), then again on the height...

Place things so that they touch on the middle is, just to help you get started.

You may revise the build to leave what little active area is free all on one side (because, if you have a screen that is placed where the projection of that "excess" area is, the pen will be able to reach it) but, as you are getting sizes, let it for after (once you got how to calibrate the build - fist time took me 30 minutes, now I do it in a couple of minutes or so).

I usually leave "all on top" -  I keep a small screen above my main drawing machine, where I leave VLC playing some series... I have enough "excess pen area" to go up and click the controls and the seek bar of VLC at full screen.

 
Okay in trying to do this! Smiley.
Also i have to see If there is some jitter i Will Say u If there is.
The main thing its that the LCD and the converter board gets really hot .. Its normal??

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