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PostPosted: Sun Aug 03, 2003 19:18 
The LCD is: Intech ITM-2002ASTL.

Anyone, tell me plz, what iz "negative voltage" - how should i use it? Should i? I have no idea... In datasheet i found something about voltages...

But when i connected my lcd to LPT i got very high temperature on chips... But whyy? i powered it with 5v - from computer's molex (not from LPT cable)... What is the problem? May i need negative voltages somwhere? Pleeez - HEEEELP!

Datashet - http://216.218.205.96/datasheets/intech/2002a-c.pdf


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PostPosted: Sun Aug 03, 2003 20:35 
Image
In another datasheet i found this pic under caption "connecting power source". Okay - i think that in first datasheet i found that the LCD is powered with +5v and -15v !!! - now how can i get from this scheme -15!!!v ??

The datasheet i found (another) http://www.promelec.ru/pdf/page_136.pdf (sorry about russian).


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PostPosted: Mon Aug 04, 2003 12:37 
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Joined: Sun May 05, 2002 22:05
Posts: 2063
Location: Lappeenranta, Finland
You can't get -15v from that. And you might not even need -15v for the display.

Usually character displays don't require external negative voltages but some low temperature models need them.

In this pdf there was something about what the ASTL letters mean in the model number: http://www.promelec.ru/pdf/page_136.pdf but as I don't understand russian I don't know what it says.


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PostPosted: Mon Aug 04, 2003 17:17 
Code:
ITM  20 02 A  S  T  L
1     2  3 4  5  6  7


1-ITM-Intech Dot-Matrix
2-20-Num. of characters.
3-02-Num of lines.
4-Revision.
5-S-STN- super twist nematic.
6-T-Transflective.
7-L-LED Backlight.

I connected my lcd as described here: http://www.overclockers.com.au/techstuff/a_diy_lcd/
stupid guide for beginners :) But in another place i found that connecting contrast pin to gnd is not recommended...


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PostPosted: Wed Aug 06, 2003 13:07 
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Joined: Sun May 05, 2002 22:05
Posts: 2063
Location: Lappeenranta, Finland
Ok, so the model number didn't reveal anything special for this problem. Have you already tried connecting the contrast like in the pic you posted ?


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PostPosted: Wed Aug 06, 2003 20:32 
Ohh :) Im so stupid... Heh - the problem was in my mind - i wanted to finish this project quickly - and forgot to check the pinouts on supplied with this LCD cable (looks like a IDE/Floppy cable with 16 wires) - i didn know that the number of pin on connector did not match the number of wire :( like follows:


Connector:
____
I1 2I
I3 4I
I5 6I
I7 8I
''''''''
Wires:

-----------------------2
-----------------------1
-----------------------4
-----------------------3
-----------------------6
-----------------------5
-----------------------8
-----------------------7

:( Now i connected everything OK - but nothing happens :(
i think that i burned LCD by connecting it with wrong polarity (just that)...

any suggestions? buy another LCD? :)


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PostPosted: Thu Aug 07, 2003 13:44 
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Joined: Sun May 05, 2002 22:05
Posts: 2063
Location: Lappeenranta, Finland
SeTuP wrote:
:( Now i connected everything OK - but nothing happens :(
i think that i burned LCD by connecting it with wrong polarity (just that)...

any suggestions? buy another LCD? :)

Usually wiring the polarity wrong is a very good way to kill the display, unfortunately. :( And when the chips get hot that's a bad sign also. Sometime they may survive but often it means they are dead.


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PostPosted: Thu Aug 07, 2003 16:38 
heh :)i think i had a good lesson - now ill never connect wires without looking at em :) This was pretty cheap lesson - costed to me just 11$ - ill buy another LCD and continue experimenting :)


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