Guest SEB Posted March 28, 2003 Report Share Posted March 28, 2003 I've a problem with my LCD, nothing is displayed on it.Can a bad connection (polarity inverted or supply on data input) destroy a LCD and how can I test it ?I bought it from Farnell, and I've never saw it work.But I'm very ;D, my box works. Quote Link to comment Share on other sites More sharing options...
Guest SEB Posted March 28, 2003 Report Share Posted March 28, 2003 I've a problem with my LCD, nothing is displayed on it.Can a bad connection (polarity inverted or supply on data input) destroy a LCD and how can I test it ?I bought it from Farnell, and I've never saw it work.But I'm very ;D, my box works. Quote Link to comment Share on other sites More sharing options...
TK. Posted March 29, 2003 Report Share Posted March 29, 2003 Hi Seb,could you tell me the farnell order number? Maybe the pinning is different to common LCDsBest Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
TK. Posted March 29, 2003 Report Share Posted March 29, 2003 Hi Seb,could you tell me the farnell order number? Maybe the pinning is different to common LCDsBest Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
Guest SEB Posted March 29, 2003 Report Share Posted March 29, 2003 Thanks Thorsten,My LCD is a TRI MODS-1535, 16 x 2 charac.Farnell order number: 142-554I've the datasheet of this product and I think is a common one.Do you know how I can test it ? Quote Link to comment Share on other sites More sharing options...
Guest SEB Posted March 29, 2003 Report Share Posted March 29, 2003 Thanks Thorsten,My LCD is a TRI MODS-1535, 16 x 2 charac.Farnell order number: 142-554I've the datasheet of this product and I think is a common one.Do you know how I can test it ? Quote Link to comment Share on other sites More sharing options...
TK. Posted March 31, 2003 Report Share Posted March 31, 2003 Hi Seb,based on the statement in this posting:http://www.industrycommunity.com/ee/ee-2/messages/521.htmlyour display possibly requires a negative voltage at pin 3 (contrast input)However, Douglas Pederick noticed the same problem with his HD44780 display and he found this solution:http://www.ucapps.de/mbhp/mbhp_lcd_neg_voltage.gifhttp://www.ucapps.de/mbhp/mbhp_lcd_neg_voltage_connection.gifWhen you study the schematic of the core module, you will notice that some components of this circuit (like the 1000uF cap and the 7805) are redundant. Just inform me if you have problems to build the circuit based on these plans, in this case I will test the circuit by myself and draw a new schematic especially for the MBHP core module --- but it can take some days until I will find the time for this.Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
TK. Posted March 31, 2003 Report Share Posted March 31, 2003 Hi Seb,based on the statement in this posting:http://www.industrycommunity.com/ee/ee-2/messages/521.htmlyour display possibly requires a negative voltage at pin 3 (contrast input)However, Douglas Pederick noticed the same problem with his HD44780 display and he found this solution:http://www.ucapps.de/mbhp/mbhp_lcd_neg_voltage.gifhttp://www.ucapps.de/mbhp/mbhp_lcd_neg_voltage_connection.gifWhen you study the schematic of the core module, you will notice that some components of this circuit (like the 1000uF cap and the 7805) are redundant. Just inform me if you have problems to build the circuit based on these plans, in this case I will test the circuit by myself and draw a new schematic especially for the MBHP core module --- but it can take some days until I will find the time for this.Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
Guest SEB Posted March 31, 2003 Report Share Posted March 31, 2003 I use an external rectified supply, and then I use only the 7805, amd some caps for the +5V. The negative voltage schematics shows the circuit supplied by an AC voltage and in my project I don't have it.I maybe will try to found an another solution for this negative voltage, and the schematics wil be usefull for my search.Thanks your reply, ThorstenI will post later for more news. Quote Link to comment Share on other sites More sharing options...
Guest SEB Posted March 31, 2003 Report Share Posted March 31, 2003 I use an external rectified supply, and then I use only the 7805, amd some caps for the +5V. The negative voltage schematics shows the circuit supplied by an AC voltage and in my project I don't have it.I maybe will try to found an another solution for this negative voltage, and the schematics wil be usefull for my search.Thanks your reply, ThorstenI will post later for more news. Quote Link to comment Share on other sites More sharing options...
Guest SEB Posted April 1, 2003 Report Share Posted April 1, 2003 I found the problem, the contraste pot was broken, and I haven't detect this before. I changed it and all is good. My LCD works.Thanks for your help Thorsten,Regards. Quote Link to comment Share on other sites More sharing options...
Guest SEB Posted April 1, 2003 Report Share Posted April 1, 2003 I found the problem, the contraste pot was broken, and I haven't detect this before. I changed it and all is good. My LCD works.Thanks for your help Thorsten,Regards. Quote Link to comment Share on other sites More sharing options...
TK. Posted April 1, 2003 Report Share Posted April 1, 2003 Fortunately...! :) Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
TK. Posted April 1, 2003 Report Share Posted April 1, 2003 Fortunately...! :) Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
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