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Help with parallel LCD - stopped working :(

Workshed

New member
I successfully wired up a hd47780 parallel LCD (20x4 lines) and have had it running with LCDSmartie for a couple of months now with no problems!
Last night i installed a UV tube in my case and windows update downloaded the Microsoft Malicious Software Removal tool (these are the only 2 things i can think of that may have affected the LCD) and at some point during the night (i didnt notice when) my LCD stopped displaying anything from LCDSmartie. The reason i mention the UV light is incase the inverter being in close proximity to the LCD may have done something to the LCD?
All it now shows are the test lines (alternate lines filled in) all the time. I've re-installed the parallel port driver (cant rember the name off hand) and i've even tried CC1 and CC2, unfortunately nothing has appeared on the LCD screen except the 2 test bars. I have tested the connections on the LCD and they all appear fine. I'll try it in another machine tonight but has anyone got any suggestions?
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X7JAY7X

New member
I have had three lcd's go bad from being hooked to the parallel port. I wasnt lucky enough to get months out of them, only days. Try it on another machine, but it is probably shot.
 

X7JAY7X

New member
That has just been my experience with parallel lcds. Dont know about others. Did you test it on another computer?

Dont know exactly why, but most LCD sellers will not carry or encourage parallel use.

I am using serial now.
 

CF Tech

Administrator
You might want to take a read of this post, it sums up our stance on the parallel LCDs connected to PC's parallel ports.

That being said, I would think some kind of ESD is the most likely culprit for early failure.
 

X7JAY7X

New member
Many places sell them because they are easy to make and they are mostly profit, what is the warranty on these?
 

CF Tech

Administrator
1) They typically have a shielded cable.

2) The data lines in the cable are intended to be exposed to the outside world, compared to the "bare logic" pins brought directly off the HD44780.

3) In a PC application, they are typically mounted in a metal bracket.

If you make a metal box, and ground the box to the shield of the parallel cable, and leave the cable plugged in (so the data lines are not exposed) then you would have some decent protection from ESD.
 

deranged

New member
I had the same problem with my lcd after a while. It turned out it was a problem with lcdsmartie even though I tried using different copies. I switched to jalcd from www.jalcds.de and it worked great. Software is a little more advanced and less user friendly but is more stable than lcdsmartie.
 
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