Dead X-Board

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GerryS
LCD?
Posts: 2
Joined: Fri Mar 31, 2006 9:41 am
Location: Canada

Dead X-Board

Post by GerryS »

Some time ago I purchased an Optrex DMC-20261NYJ-LY-BCE module from DigiKey. This is an extended operating temperature 2X20 LCD with a backlight.

Earlier this week I finally got the X-Board from HVW Technologies.

Last night I put the two together. When I applied 5VDC to the system, nothing happened. I managed to get the backlight to come on but no character display of any kind.

The two boards go together using the 2x8 header assembly, which had to be modified. Basically pins 1-14 bus to the display but 15 and 16 do not so I removed a pin from the interconnecting header and ran wires from the X-board to the A and K terminals on the backlight.

Any advice? I have no way of knowing if the X-board is toast or if the Optrex LCD module is defective. Both parts are new and have never been used. And as Murphy would have it, both are now soldered together. I did check for cold solder joints but everything looks good and rings out okay using the continuity check on my DVM.

Thanks in advance for your help.

Regards,

Gerry Shand
Gerry Shand

Raquel
Matrix Orbital
Matrix Orbital
Posts: 731
Joined: Thu Aug 19, 2004 3:37 pm
Location: MO Office

Post by Raquel »

Hi Gerry,

I am sorry to hear that Murphy got to you (who does he not get to, huh?) Would you happen to have a scope? Can you please scope out pin 3 which is the Vee (contrast) for the display. There should be some form of PWM on this pin, but between 0 to 5V.

I have a feeling contrast is too low that you can not see text. Try viewing the display on different angles as well that you might hopefully see some text.

Please let me know your findings.
Raquel Malinis
Design and Development
Matrix Orbital

GerryS
LCD?
Posts: 2
Joined: Fri Mar 31, 2006 9:41 am
Location: Canada

Dead X-Board

Post by GerryS »

Hi Raquel:

I did try and view the display at different angles and could not see anything in the way of characters as I thought the contrast would be turned down as well.

I do have a scope and will get a look at pin 3 this weekend. Should let you know early next week what I find.

I also thought the backlight would be draining down the 5VDC supply but that is not the case so we can also eliminate resets due to voltage brownouts.

Regards,
Gerry Shand

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