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I Bought a NanTan.....again....and fun reverse engineering LCD panels....

creepingnet

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Feb 25, 2005
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So it was about, uh, 15-20 years ago I got into this crazy hobby because I wannted a computer, could not afford one, and started using cast-off 486s as my primary machine of choice. This would lead me down a path to a 20-ish year long (thus far) career in I.T. as well as a side hustle of screwing around with vintage PC hardware. Well, when this DFI MediaBook NP92/9200M/FMA9200 (NanTan FMAK9200) showed up on e-bay, I could not resist nabbing it, as I remember the 9200 being quite a nice computer back in 2003-2005 when it was my main and primary laptop computer for darn near antyhing I need a portable for.duracom5110D2005.jpg To the left we have the new specimen, the DFI, and to the right, we have my O.G. back in 2004 - the Duracom 5110D - which was the same model, but with a DTSN Color screen on it.

I bought the Duracom as a part o f a "stack" of "3 old laptops" on evil-bay back in 2004 for about $45 (it came with a n AT&T Safari 3151 - the computer that indirectly lead me to the NEC Versa, and a NanTan Notebook FMA3500 as well). Back then, I remember googling and Yahoo! searching EVERYWHERE trying to find out what the heck these were and find any info on them. There was no google books (so I could never find out when they tested 4-5 of the same computer by 5 different manufacturers in PC Magazine), there was no YouTube, and even now I'm the FIRST person I have ever seen or heard of on YouTube with one of these laptops. They are sort of like the GEM 386/20 that way - you can't find much info on them - because some Chinese conglomerate (in this case NTC, or NanTan Computer, aka Kapok, aka Clevo) made the machine, and silkscreened someone else's logo on them (High Screen, Duracom, Eurocom, DFI, Prostar, Sager, Hyperbook....and the list goes on and on).

My motivation for nabbing one of these was so that I could try it out again as a retro-DOS platform and see if it still stands up well today. Well, the unit I got is a STN Monochrome model with a Casio MD820TT00-C1 panel, a 486 SX-25 CPU that was acting more like a DX-33, and I leanred where the Startup Chime for it is located (because I never knew these had one until I flipped Dip Switch#1 looking for a way to change the System Bus to 33MHz after putting a Intel DX2-66 in there).
But it has started me down a rabbit-hole of looking into LCD Panel technologies, as there are a lot of otherwise cool 486 laptops out there (or even older) that could possibly be capable of color, if not an Active Matrix Panel.

Panel Displays - What I Have Learned (from the DFI and the Versa)

So, out of curiosity, I started looking into what it would take to convert the DFI to color and/or active matrix, and this is what I learned....and how I learned. It also gives some insight into the methods I use when figuring out things.

On vintage laptops, there are three types of screen: STN Monochrome, DTSN Color, and Active Matrix Thin-Film-Transistor - or TFT for short.

STN Monochrome screens typically have 14-16 pin connections on a single wire, the 14 pin units don't have an on-board ballast on the screen for the CCFL backlight(s). Those with more pins do. I did some digging and found a article on salvaging LCDs and found a general pinout to go by that might work....typically it consists of sync for halves of the screen - https://www.instructables.com/Salvaging-Liquid-Crystal-Displays-LCDs/

The general pinout is
  1. VSS - 0volts to ground
  2. VDD - +3 or +5 volts power supply
  3. VO - Contrast Adjustment
  4. RS - Register Select, high signal = Data, low signal = instruuction
  5. R/Ww - Read/Write Select Signal, low = Write, high = read
  6. E - Enable Panel signal
  7. DB0 - Data Bus 0
  8. DB1 - Data Bus 1
  9. DB2 - Data Bus 2
  10. DB3 - Data Bus 3
  11. DB4 - Data Bus 4
  12. DB5 - Data Bus 5
  13. DB6 - Data Bus 6
  14. DB7 - Data Bus 7
  15. A/Vee - Backlight Anode +4.2 volts
  16. K - Backlight Cathode Power ground.

DTSN Screens are similar but include 2 Latches - per the Sharp LM64C031 640x480 9.4" LCD Single Scan STN LCD Pinout below - this is a Color LCD - it has 18 pins and the Ballast for the backlights, I assume, is an external part.

  1. Startup
  2. Latch Data
  3. Lower Data Clock
  4. Upper Data clock
  5. NC
  6. Power Supply, Logic & LCD
  7. Ground
  8. Power Supply for LCD
  9. Ground
  10. Data 0
  11. Data 1
  12. Data 2
  13. Data 3
  14. Data 4
  15. Data 5
  16. Data 6
  17. Data 7
  18. Ground
And then there's a secondary six pin for the CCFL

  1. High voltage Line for CCFL (from Inverter)
  2. NC
  3. GND
  4. GND
  5. NC
  6. High voltage line for CCFL (from invereter)

It looks to me, by adding color, we have added the additional Data Latches for color control it seems. Correct me if I'm mistaken. Much of the rest of the pinout matches the "standard" STN pinout given in the tutorial (where I got it from) above this panel's pinout.

Now Active Matrix is way more complex.....Now we will look at the pinout for several NEC panels - the same ones from my NEC Versas actually (NL6448AC30-03/06/10 and NL8060AC24-01 800x600). Alll of these are 4096 color Active Matrix TFT panels of 9.4" in size, and ll of them are interchangable with each other. I also noticed on the NEC laptops, there's no extra boards inside the screen, the wires go from either a connector board with maybe a multiplexer chip on it, and a couple resistors at most, and then go into the screen direct which has it's own dedicated logic and CCFL inverter boards built into it. Basically, all these signals go into the logic board, and the PCB passes the inverter signals through it into a flat Cable that runs to the inverter board on the other side of the back of the screen. I also noticed these screens have not one but TWO places for the brightness adjustment slider so you could use this panel in other machines with it on the other side. All the brightness adjustment is - is a sliding potentiometer, sort of like the kind found in a studio mixing desk.

Anyway, here's the pinout

CN1 - 10 pin
  1. CLK
  2. GND
  3. GND
  4. Horizontal Sync
  5. Vertical Sync
  6. GND
  7. Red Data 0 (LSB - Left Side Bus?)
  8. Red Data 1
  9. Red Data 2
  10. Red Data 3 (RSB - Right Side Bus?)
CN2 - 13 pin
  1. GND
  2. Green Data 0 (LSB)
  3. Green Data 1
  4. Green Data 2
  5. Green Data 3 (RSB)
  6. GND
  7. Blue Data 0 (LSB)
  8. Blue Data 1
  9. Blue Data 2
  10. Blue Data 3 (RSB)
  11. GND
  12. Ac Adapter in (Voltage+?)
  13. Backlight On/Off
CN3 - 11 pin
  1. GND
  2. VCC - Voltage, Logic
  3. VDD - Voltage, Backlight Circuit (Inverter Board passthru-logic?)
  4. VDD - Voltage, Backlight (2nd for the 03/06 boarrds with 2 CCFLS?)
  5. NC
  6. GND B - Backlight Ground (corresponds to pin 3?)
  7. GND B - Backlight Ground (corresponds to pin 4?)
  8. Data Enable
  9. Mode
  10. VCC Power off (APM Control perhaps?)
  11. GND

So what see here is the individual banks of transistors get their data from 4-bit registers per color - 4 for red, 4 for green, 4 for blue, with the first one for the Left Side Bus and the last for a Right Side bus possibly (how the screen is split). It appears there are 2 voltage connections, meaning one could probably power up the screen using an AC Adapter using the input given on pin 12 of connector 2.

But what made me a bit giddy was that when I took apart the NanTan, it has a similar setup to the versa inside.....

The Graphics chipset is likely near the center, on the other side of the board. The connectors are right under the keyboard, and like the NEC Versa, there are THREE of them, each going to their own connectors. These three plug into a board inside the screen assembly that splits off into one 14 pin cable that runs to the LCD, and then a series of chokes and a transformer for the power to the CCFL backlight. The idea I have is if I can figure out the pinout to the graphics cables, and match the data lines up to a NLt6448AC30 - I could very likely put a TFT Active Matrix NEC panel in this laptop computer. The screw holes even seemed to match (are industrial panels standardized in hole placement?).

So it just might be there IS a way o upgrade some of these older laptops to TFT, or at least color.
 
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