LCD help

Parts Questions
1

I’ve put down a bid on the following LCD - a low enough bid to take the chance on it working - but I thought I’d better ask around and see if anyone can advise me before I bid any higher.  

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=2548263627

20 x 2 Alphanumeric LCD display

OPTREX DMC2059

This display has an Orange backlight (approx 14V)

Extended temperature operation.

Requires -7v bias for contrast control.

Large Character format.

I can’t find a spec sheet matching that model number on the OPtrex website, or via Google.  It’s for the MIDIbox SID and the 16E or 64.

Any advice would be appreciated.

2

I guess that this display is HD44780 compatible, but I wouldn’t buy it - the high backlight voltage requires a second power supply unit, and for the -7V bias voltage you’ve to use a DC/DC voltage converter like shown here: http://www.ucapps.de/mbhp/mbhp_glcd0.pdf

In fact it will cost you more (trouble) than a common LCD.

Best Regards, Thorsten.

3

Hey Dr B,

if you can use 16x2, Dick Smith carry an LED backlit (green) device that worked fine for me, but for AUS$38 it is very expensive!!!

4

I received the following reply from the seller:

I have an equivilent datasheet for these displays on my computer at home.

They are standard HD44780 compatible LCD, they are large font extendend temperature.

This particular display was a custom manufacture from Optrex, they work well, and are standard except for the backlight which has the current limiting resistors designed for an input voltage of 13-14v.

The extended temp operation is similar for all optrex LCD’s, they

require -7V bias for contrast.

I usually steal -10V through a 10k pot from a max232 or similar, it only requires 1mA or so…

I will email you a copy of the datasheet I have when I get home later today.

Thanks for your reply TK.  He also has two 20x4 displays for sale; could I use them in the MIDIBoxen?