This is my first LCD and I am not having much luck. I have checked over
my wiring many many times and cannot seem to find the problem. It is a
4x20 hd4780 LCD. When I turn it on the backlight comes on and I receive
the test signal, but some lines are missing. The top 4 squares, or I
guess pixels, are on but then the next 2 down are not. The bottom 2 are
also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the LCD.
Is this a bad LCD or do I have my wiring wrong? Also, I can use LCD
Smartie and the LCD will respond but I can only make out some
characters, but most of the screen is gibberish. How can I go about
fixing this problem? Any help will be appreciated. Thanks,
Chris

"Chris Fonville" schreef in bericht
...
This is my first LCD and I am not having much luck. I have checked over
my wiring many many times and cannot seem to find the problem. It is a
4x20 hd4780 LCD. When I turn it on the backlight comes on and I receive
the test signal, but some lines are missing. The top 4 squares, or I
guess pixels, are on but then the next 2 down are not. The bottom 2 are
also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the LCD. Is
this a bad LCD or do I have my wiring wrong? Also, I can use LCD Smartie
and the LCD will respond but I can only make out some characters, but most
of the screen is gibberish. How can I go about fixing this problem? Any
help will be appreciated. Thanks,
Chris

Chris,

normally you send the ascii code of a character to the LCD (controller), if
this character is displayed on one or more line(s) correctly, you have
initialized and send a succesfully this character. If you only use the
controller's own characters this character is always displayed correctly, if
this character is missing a line (or more) then most likely the display is
broken.
So in your case send one character to all positions, you should see 4*20 of
the same character (or one different because of cursor), if not try another
display.

Good luck,

Alex

Alexander wrote:
"Chris Fonville" schreef in bericht
...

This is my first LCD and I am not having much luck. I have checked over
my wiring many many times and cannot seem to find the problem. It is a
4x20 hd4780 LCD. When I turn it on the backlight comes on and I receive
the test signal, but some lines are missing. The top 4 squares, or I
guess pixels, are on but then the next 2 down are not. The bottom 2 are
also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the LCD. Is
this a bad LCD or do I have my wiring wrong? Also, I can use LCD Smartie
and the LCD will respond but I can only make out some characters, but most
of the screen is gibberish. How can I go about fixing this problem? Any
help will be appreciated. Thanks,
Chris


Chris,

normally you send the ascii code of a character to the LCD (controller), if
this character is displayed on one or more line(s) correctly, you have
initialized and send a succesfully this character. If you only use the
controller's own characters this character is always displayed correctly, if
this character is missing a line (or more) then most likely the display is
broken.
So in your case send one character to all positions, you should see 4*20 of
the same character (or one different because of cursor), if not try another
display.

Good luck,

Alex



The example I posted above was just from the test screen. This happens
when the LCD is not connected to the parallel port, but is just
receiving power. If I understand correctly, every other line of the 4
should be on. This happens with mine, however each character is 8
blocks or pixels high and only the top 4 are on, 2 are not, then the
bottom 2 are on. This happens all the way across the screen. This is
hard to explain in words, I have uploaded some pictures:
Test screen with and without parallel connection
http://www.chriscomputers.com/lcdtest.jpg
Using LCD Smartie to put "ABC" on all 4 lines
http://www.chriscomptuers.com/lcdabc.jpg

You can sort of make out ABC in lines 2 and 4. Because I can actually
send it commands and it display them somewhat, and because the LCD test
screen is not fully working with just power, I think it is either my
power wiring is wrong or the LCD is defective. Thank you for your help,
Chris

"Chris Fonville" schreef in bericht
...
Alexander wrote:
"Chris Fonville" schreef in bericht
...

This is my first LCD and I am not having much luck. I have checked over
my wiring many many times and cannot seem to find the problem. It is a
4x20 hd4780 LCD. When I turn it on the backlight comes on and I receive
the test signal, but some lines are missing. The top 4 squares, or I
guess pixels, are on but then the next 2 down are not. The bottom 2 are
also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the LCD.
Is this a bad LCD or do I have my wiring wrong? Also, I can use LCD
Smartie and the LCD will respond but I can only make out some characters,
but most of the screen is gibberish. How can I go about fixing this
problem? Any help will be appreciated. Thanks,
Chris


Chris,

normally you send the ascii code of a character to the LCD (controller),
if this character is displayed on one or more line(s) correctly, you have
initialized and send a succesfully this character. If you only use the
controller's own characters this character is always displayed correctly,
if this character is missing a line (or more) then most likely the
display is broken.
So in your case send one character to all positions, you should see 4*20
of the same character (or one different because of cursor), if not try
another display.

Good luck,

Alex

The example I posted above was just from the test screen. This happens
when the LCD is not connected to the parallel port, but is just receiving
power. If I understand correctly, every other line of the 4 should be on.
This happens with mine, however each character is 8 blocks or pixels high
and only the top 4 are on, 2 are not, then the bottom 2 are on. This
happens all the way across the screen. This is hard to explain in words,
I have uploaded some pictures:
Test screen with and without parallel connection
http://www.chriscomputers.com/lcdtest.jpg
Using LCD Smartie to put "ABC" on all 4 lines
http://www.chriscomptuers.com/lcdabc.jpg

You can sort of make out ABC in lines 2 and 4. Because I can actually
send it commands and it display them somewhat, and because the LCD test
screen is not fully working with just power, I think it is either my power
wiring is wrong or the LCD is defective. Thank you for your help,
Chris

It looks like a defective LCD-Module, but I have never seen a similar
problem, try disconnecting the enable line or shutting down the device that
gives command to the LCD is the ABC stays the same way it's the LCD-Module.
If it changes and gives either blocks or good ABC then you are changing what
the module should display rather fast.

Good luck,

Alex

"Chris Fonville" schreef in bericht
...
Alexander wrote:
"Chris Fonville" schreef in bericht
...

This is my first LCD and I am not having much luck. I have checked over
my wiring many many times and cannot seem to find the problem. It is a
4x20 hd4780 LCD. When I turn it on the backlight comes on and I receive
the test signal, but some lines are missing. The top 4 squares, or I
guess pixels, are on but then the next 2 down are not. The bottom 2 are
also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the LCD.
Is this a bad LCD or do I have my wiring wrong? Also, I can use LCD
Smartie and the LCD will respond but I can only make out some characters,
but most of the screen is gibberish. How can I go about fixing this
problem? Any help will be appreciated. Thanks,
Chris


Chris,

normally you send the ascii code of a character to the LCD (controller),
if this character is displayed on one or more line(s) correctly, you have
initialized and send a succesfully this character. If you only use the
controller's own characters this character is always displayed correctly,
if this character is missing a line (or more) then most likely the
display is broken.
So in your case send one character to all positions, you should see 4*20
of the same character (or one different because of cursor), if not try
another display.

Good luck,

Alex

The example I posted above was just from the test screen. This happens
when the LCD is not connected to the parallel port, but is just receiving
power. If I understand correctly, every other line of the 4 should be on.
This happens with mine, however each character is 8 blocks or pixels high
and only the top 4 are on, 2 are not, then the bottom 2 are on. This
happens all the way across the screen. This is hard to explain in words,
I have uploaded some pictures:
Test screen with and without parallel connection
http://www.chriscomputers.com/lcdtest.jpg
Using LCD Smartie to put "ABC" on all 4 lines
http://www.chriscomptuers.com/lcdabc.jpg

You can sort of make out ABC in lines 2 and 4. Because I can actually
send it commands and it display them somewhat, and because the LCD test
screen is not fully working with just power, I think it is either my power
wiring is wrong or the LCD is defective. Thank you for your help,
Chris

If you connect the first three pins only Vss, Vdd and Vo, the first line
(and perhaps the third line) should be all blocks with the character width
and height.

Alexander wrote:
"Chris Fonville" schreef in bericht
...

Alexander wrote:

"Chris Fonville" schreef in bericht
...


This is my first LCD and I am not having much luck. I have checked over
my wiring many many times and cannot seem to find the problem. It is a
4x20 hd4780 LCD. When I turn it on the backlight comes on and I receive
the test signal, but some lines are missing. The top 4 squares, or I
guess pixels, are on but then the next 2 down are not. The bottom 2 are
also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the LCD.
Is this a bad LCD or do I have my wiring wrong? Also, I can use LCD
Smartie and the LCD will respond but I can only make out some characters,
but most of the screen is gibberish. How can I go about fixing this
problem? Any help will be appreciated. Thanks,
Chris


Chris,

normally you send the ascii code of a character to the LCD (controller),
if this character is displayed on one or more line(s) correctly, you have
initialized and send a succesfully this character. If you only use the
controller's own characters this character is always displayed correctly,
if this character is missing a line (or more) then most likely the
display is broken.
So in your case send one character to all positions, you should see 4*20
of the same character (or one different because of cursor), if not try
another display.

Good luck,

Alex

The example I posted above was just from the test screen. This happens
when the LCD is not connected to the parallel port, but is just receiving
power. If I understand correctly, every other line of the 4 should be on.
This happens with mine, however each character is 8 blocks or pixels high
and only the top 4 are on, 2 are not, then the bottom 2 are on. This
happens all the way across the screen. This is hard to explain in words,
I have uploaded some pictures:
Test screen with and without parallel connection
http://www.chriscomputers.com/lcdtest.jpg
Using LCD Smartie to put "ABC" on all 4 lines
http://www.chriscomptuers.com/lcdabc.jpg

You can sort of make out ABC in lines 2 and 4. Because I can actually
send it commands and it display them somewhat, and because the LCD test
screen is not fully working with just power, I think it is either my power
wiring is wrong or the LCD is defective. Thank you for your help,
Chris


It looks like a defective LCD-Module, but I have never seen a similar
problem, try disconnecting the enable line or shutting down the device that
gives command to the LCD is the ABC stays the same way it's the LCD-Module.
If it changes and gives either blocks or good ABC then you are changing what
the module should display rather fast.

Good luck,

Alex



I have tried changing the timing multiplier from 1 to 5 (the max) in LCD
Smartie, but it only refreshes the LCD, there is no effect to what is
displayed. When I close the LCD Smartie program the LCD goes blank
(although the 1st and 3rd lines do very faintly appear, still with the
missing pixels). I will desolder all the wires and see what happens
with just pins 1, 2, and 3 attached to ground, +5 volts, and ground
respectively and post back here with the results. Thank you,
Chris

Alexander wrote:
"Chris Fonville" schreef in bericht
...

Alexander wrote:

"Chris Fonville" schreef in bericht
...


This is my first LCD and I am not having much luck. I have checked over
my wiring many many times and cannot seem to find the problem. It is a
4x20 hd4780 LCD. When I turn it on the backlight comes on and I receive
the test signal, but some lines are missing. The top 4 squares, or I
guess pixels, are on but then the next 2 down are not. The bottom 2 are
also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the LCD.
Is this a bad LCD or do I have my wiring wrong? Also, I can use LCD
Smartie and the LCD will respond but I can only make out some characters,
but most of the screen is gibberish. How can I go about fixing this
problem? Any help will be appreciated. Thanks,
Chris


Chris,

normally you send the ascii code of a character to the LCD (controller),
if this character is displayed on one or more line(s) correctly, you have
initialized and send a succesfully this character. If you only use the
controller's own characters this character is always displayed correctly,
if this character is missing a line (or more) then most likely the
display is broken.
So in your case send one character to all positions, you should see 4*20
of the same character (or one different because of cursor), if not try
another display.

Good luck,

Alex

The example I posted above was just from the test screen. This happens
when the LCD is not connected to the parallel port, but is just receiving
power. If I understand correctly, every other line of the 4 should be on.
This happens with mine, however each character is 8 blocks or pixels high
and only the top 4 are on, 2 are not, then the bottom 2 are on. This
happens all the way across the screen. This is hard to explain in words,
I have uploaded some pictures:
Test screen with and without parallel connection
http://www.chriscomputers.com/lcdtest.jpg
Using LCD Smartie to put "ABC" on all 4 lines
http://www.chriscomptuers.com/lcdabc.jpg

You can sort of make out ABC in lines 2 and 4. Because I can actually
send it commands and it display them somewhat, and because the LCD test
screen is not fully working with just power, I think it is either my power
wiring is wrong or the LCD is defective. Thank you for your help,
Chris


If you connect the first three pins only Vss, Vdd and Vo, the first line
(and perhaps the third line) should be all blocks with the character width
and height.



With only the first 3 pins wired I receive the same test screen, without
the backlight. (http://www.chriscomputers.com/lcdtest.jpg)
Pin 1 - Ground
Pin 2 - +5 volts
Pin 3 - Ground

So I am pretty sure it's a defective LCD. However, is this problem
because of bad wiring on my part, or did I simply receive a bad unit?
Thank you for your help,
Chris

"Chris Fonville" schreef in bericht
...
Alexander wrote:
"Chris Fonville" schreef in bericht
...

Alexander wrote:

"Chris Fonville" schreef in bericht
...


This is my first LCD and I am not having much luck. I have checked
over my wiring many many times and cannot seem to find the problem. It
is a 4x20 hd4780 LCD. When I turn it on the backlight comes on and I
receive the test signal, but some lines are missing. The top 4
squares, or I guess pixels, are on but then the next 2 down are not.
The bottom 2 are also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the LCD.
Is this a bad LCD or do I have my wiring wrong? Also, I can use LCD
Smartie and the LCD will respond but I can only make out some
characters, but most of the screen is gibberish. How can I go about
fixing this problem? Any help will be appreciated. Thanks,
Chris


Chris,

normally you send the ascii code of a character to the LCD (controller),
if this character is displayed on one or more line(s) correctly, you
have initialized and send a succesfully this character. If you only use
the controller's own characters this character is always displayed
correctly, if this character is missing a line (or more) then most
likely the display is broken.
So in your case send one character to all positions, you should see 4*20
of the same character (or one different because of cursor), if not try
another display.

Good luck,

Alex

The example I posted above was just from the test screen. This happens
when the LCD is not connected to the parallel port, but is just receiving
power. If I understand correctly, every other line of the 4 should be
on. This happens with mine, however each character is 8 blocks or pixels
high and only the top 4 are on, 2 are not, then the bottom 2 are on.
This happens all the way across the screen. This is hard to explain in
words, I have uploaded some pictures:
Test screen with and without parallel connection
http://www.chriscomputers.com/lcdtest.jpg
Using LCD Smartie to put "ABC" on all 4 lines
http://www.chriscomptuers.com/lcdabc.jpg

You can sort of make out ABC in lines 2 and 4. Because I can actually
send it commands and it display them somewhat, and because the LCD test
screen is not fully working with just power, I think it is either my
power wiring is wrong or the LCD is defective. Thank you for your help,
Chris


If you connect the first three pins only Vss, Vdd and Vo, the first line
(and perhaps the third line) should be all blocks with the character
width and height.

With only the first 3 pins wired I receive the same test screen, without
the backlight. (http://www.chriscomputers.com/lcdtest.jpg)
Pin 1 - Ground
Pin 2 - +5 volts
Pin 3 - Ground

So I am pretty sure it's a defective LCD. However, is this problem
because of bad wiring on my part, or did I simply receive a bad unit?
Thank you for your help,
Chris

Chris,

That's a good question in my experience (production lin also) there are
always some bad unit's, some with a similar problem.
The problem may also be caused by e.g. ESD or simply by cutting the display
out of the package and damaging the traces of the PCB. Or you might even
have previously connected it wrong.

Because of this problem many retailers don't take any Electronical
Components back, so you're probably out of luck with this one.

Better luck next time,

Alexander

Alexander wrote:
"Chris Fonville" schreef in bericht
...

Alexander wrote:

"Chris Fonville" schreef in bericht
...


Alexander wrote:


"Chris Fonville" schreef in bericht
...



This is my first LCD and I am not having much luck. I have checked
over my wiring many many times and cannot seem to find the problem. It
is a 4x20 hd4780 LCD. When I turn it on the backlight comes on and I
receive the test signal, but some lines are missing. The top 4
squares, or I guess pixels, are on but then the next 2 down are not.
The bottom 2 are also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the LCD.
Is this a bad LCD or do I have my wiring wrong? Also, I can use LCD
Smartie and the LCD will respond but I can only make out some
characters, but most of the screen is gibberish. How can I go about
fixing this problem? Any help will be appreciated. Thanks,
Chris


Chris,

normally you send the ascii code of a character to the LCD (controller),
if this character is displayed on one or more line(s) correctly, you
have initialized and send a succesfully this character. If you only use
the controller's own characters this character is always displayed
correctly, if this character is missing a line (or more) then most
likely the display is broken.
So in your case send one character to all positions, you should see 4*20
of the same character (or one different because of cursor), if not try
another display.

Good luck,

Alex

The example I posted above was just from the test screen. This happens
when the LCD is not connected to the parallel port, but is just receiving
power. If I understand correctly, every other line of the 4 should be
on. This happens with mine, however each character is 8 blocks or pixels
high and only the top 4 are on, 2 are not, then the bottom 2 are on.
This happens all the way across the screen. This is hard to explain in
words, I have uploaded some pictures:
Test screen with and without parallel connection
http://www.chriscomputers.com/lcdtest.jpg
Using LCD Smartie to put "ABC" on all 4 lines
http://www.chriscomptuers.com/lcdabc.jpg

You can sort of make out ABC in lines 2 and 4. Because I can actually
send it commands and it display them somewhat, and because the LCD test
screen is not fully working with just power, I think it is either my
power wiring is wrong or the LCD is defective. Thank you for your help,
Chris


If you connect the first three pins only Vss, Vdd and Vo, the first line
(and perhaps the third line) should be all blocks with the character
width and height.

With only the first 3 pins wired I receive the same test screen, without
the backlight. (http://www.chriscomputers.com/lcdtest.jpg)
Pin 1 - Ground
Pin 2 - +5 volts
Pin 3 - Ground

So I am pretty sure it's a defective LCD. However, is this problem
because of bad wiring on my part, or did I simply receive a bad unit?
Thank you for your help,
Chris


Chris,

That's a good question in my experience (production lin also) there are
always some bad unit's, some with a similar problem.
The problem may also be caused by e.g. ESD or simply by cutting the display
out of the package and damaging the traces of the PCB. Or you might even
have previously connected it wrong.

Because of this problem many retailers don't take any Electronical
Components back, so you're probably out of luck with this one.

Better luck next time,

Alexander



It might have been ESD but I always touch metal before handling any
components and this was no exception. The package was closed with a
string and so I did not damage it when unpacking it. Also, unless my
first wiring was wrong, it was the only way I tried it. I received this
LCD from eBay for $10 + $5 shipping. The seller has refunded my $10 but
I am only out $5. I might try to buy from another seller, but like you
said they all seem to have a no refund, no return policy. I guess I am
lucky to get my $10 back. Any ideas on where I could get a cheap 20x4
backlit LCD from an internet retailer? Thank you for your help,
hopefully if I do get another unit I won't be back here looking for
help! Thanks again,
Chris

"Chris Fonville" schreef in bericht
...
Alexander wrote:
"Chris Fonville" schreef in bericht
...

Alexander wrote:

"Chris Fonville" schreef in bericht
...


Alexander wrote:


"Chris Fonville" schreef in bericht
...



This is my first LCD and I am not having much luck. I have checked
over my wiring many many times and cannot seem to find the problem.
It is a 4x20 hd4780 LCD. When I turn it on the backlight comes on
and I receive the test signal, but some lines are missing. The top 4
squares, or I guess pixels, are on but then the next 2 down are not.
The bottom 2 are also on. Here is an example of one character:
*****
*****
*****


*****
*****
This is repeated for each character on the 1st and 3rd line of the
LCD. Is this a bad LCD or do I have my wiring wrong? Also, I can use
LCD Smartie and the LCD will respond but I can only make out some
characters, but most of the screen is gibberish. How can I go about
fixing this problem? Any help will be appreciated. Thanks,
Chris


Chris,

normally you send the ascii code of a character to the LCD
(controller), if this character is displayed on one or more line(s)
correctly, you have initialized and send a succesfully this character.
If you only use the controller's own characters this character is
always displayed correctly, if this character is missing a line (or
more) then most likely the display is broken.
So in your case send one character to all positions, you should see
4*20 of the same character (or one different because of cursor), if
not try another display.

Good luck,

Alex

The example I posted above was just from the test screen. This happens
when the LCD is not connected to the parallel port, but is just
receiving power. If I understand correctly, every other line of the 4
should be on. This happens with mine, however each character is 8
blocks or pixels high and only the top 4 are on, 2 are not, then the
bottom 2 are on. This happens all the way across the screen. This is
hard to explain in words, I have uploaded some pictures:
Test screen with and without parallel connection
http://www.chriscomputers.com/lcdtest.jpg
Using LCD Smartie to put "ABC" on all 4 lines
http://www.chriscomptuers.com/lcdabc.jpg

You can sort of make out ABC in lines 2 and 4. Because I can actually
send it commands and it display them somewhat, and because the LCD test
screen is not fully working with just power, I think it is either my
power wiring is wrong or the LCD is defective. Thank you for your
help,
Chris


If you connect the first three pins only Vss, Vdd and Vo, the first line
(and perhaps the third line) should be all blocks with the character
width and height.

With only the first 3 pins wired I receive the same test screen, without
the backlight. (http://www.chriscomputers.com/lcdtest.jpg)
Pin 1 - Ground
Pin 2 - +5 volts
Pin 3 - Ground

So I am pretty sure it's a defective LCD. However, is this problem
because of bad wiring on my part, or did I simply receive a bad unit?
Thank you for your help,
Chris


Chris,

That's a good question in my experience (production lin also) there are
always some bad unit's, some with a similar problem.
The problem may also be caused by e.g. ESD or simply by cutting the
display out of the package and damaging the traces of the PCB. Or you
might even have previously connected it wrong.

Because of this problem many retailers don't take any Electronical
Components back, so you're probably out of luck with this one.

Better luck next time,

Alexander

It might have been ESD but I always touch metal before handling any
components and this was no exception. The package was closed with a
string and so I did not damage it when unpacking it. Also, unless my
first wiring was wrong, it was the only way I tried it. I received this
LCD from eBay for $10 + $5 shipping. The seller has refunded my $10 but I
am only out $5. I might try to buy from another seller, but like you said
they all seem to have a no refund, no return policy. I guess I am lucky
to get my $10 back. Any ideas on where I could get a cheap 20x4 backlit
LCD from an internet retailer? Thank you for your help, hopefully if I do
get another unit I won't be back here looking for help! Thanks again,
Chris

Nope,

I don't have any use for electronic components of the internet, at work we
buy them in large quantities and that's much cheaper than the internet.