14pin vs 16 pin 20x2 character backlit LCD?

[Dan Nigrin]

I am trying to replace a 20x2 character LCD in a piece of gear that I
own. It is a Data Vision DV-20200, S1MBLY LCD, here are the specs:

http://www.datavision.com.tw/english/table/dvtable/dv20200.htm

I don't know exactly whether I have an TN, STN, EL or whatever, but I'm
almost positive it is backlit; although it is NOT this unit, it looked
exactly like this when it was working, yellow backlight and all:

http://character-lcd-lcds.shopeio.com/inventory/enlargeimage.asp?id=938

Now for my problem - my existing broken LCD has only 14 pins, whereas
every replacement one I've seen has 16 pins. As I understand, those
last two pins are the ones that supply power to the backlight.

Is it possible that I can have a backlit LCD with only 14 pins? And if
so, where can I find a suitable replacement?

Thanks,
Dan

 

[Wolfgang Mahringer]

Hi Dan,

I am trying to replace a 20x2 character LCD in a piece of gear that I
own. It is a Data Vision DV-20200, S1MBLY LCD, here are the specs:

http://www.datavision.com.tw/english/table/dvtable/dv20200.htm

Dysfunctional site, so I can't say anything on this one.

I don't know exactly whether I have an TN, STN, EL or whatever, but I'm
almost positive it is backlit; although it is NOT this unit, it looked
exactly like this when it was working, yellow backlight and all:

http://character-lcd-lcds.shopeio.com/inventory/enlargeimage.asp?id=938

On most 16pin "industry standard" LCD modules pins 15 and 16 are more or
less directly connected to A and K you see on the right of that picture.
Of course this only applies to LED backlights, not EL!

Now for my problem - my existing broken LCD has only 14 pins, whereas
every replacement one I've seen has 16 pins. As I understand, those
last two pins are the ones that supply power to the backlight.

Is it possible that I can have a backlit LCD with only 14 pins?

Sure. There must be A and K terminals then. Just wire them up, but
try a 470 ohm resistor in series first.

And if
so, where can I find a suitable replacement?

You can use any of these displays you can get, if it is same size
and character/lines number.
But take care: there is some sort of contrast control voltage
(V_lcd, pin 3).
Usually, this voltage is between 0 and +5 Volts.
Sometimes there are LCD modules which want a negative contrast voltage.
Mostly these are modules for an extended temperature range.
It is best to measure what voltage you have on pin 3 and then pick
a suitable replacement.

HTH
Wolfgang

 

[Roger Hamlett]

I am trying to replace a 20x2 character LCD in a piece of gear that I
own. It is a Data Vision DV-20200, S1MBLY LCD, here are the specs:

http://www.datavision.com.tw/english/table/dvtable/dv20200.htm

I don't know exactly whether I have an TN, STN, EL or whatever, but I'm
almost positive it is backlit; although it is NOT this unit, it looked
exactly like this when it was working, yellow backlight and all:

http://character-lcd-lcds.shopeio.com/inventory/enlargeimage.asp?id=938

Now for my problem - my existing broken LCD has only 14 pins, whereas
every replacement one I've seen has 16 pins. As I understand, those
last two pins are the ones that supply power to the backlight.

Is it possible that I can have a backlit LCD with only 14 pins? And if
so, where can I find a suitable replacement?

Thanks,
Dan

Many manufacturers offer these modules, and 99.9%, are directly compatible
(using 'clones' of the old Hitachi controller chip). Most offer different
pinout options. So (for instance), Powertip, offer the 'PC1602-H', with a
16 pin conector, or the 'PC1602-I', and the 'PC1602-J', both with a 14 pin
DIL connector. Then you have versions with 14, and 16 pin SIL connections,
above, and below the display. In many cases, the 14 pin version has been
dropped, since you can just use the lower 14 pins, and not connect to the
top two pins, with the seperate backlight connection at the other end of
the board. Also some of the newer modules offer a jumper/solder pad, to
power the backlight (only on LED backlit versions), from the 5v connection
feeding the logic. Some, have the 16pins, but don't bother to even make
the upper two connections. Have a talk to somebody like CrystalFontz, and
they should be able to do you a version of the CFAH1602, that runs from a
single power connection.

Best Wishes

 

[Dan Nigrin]

Many manufacturers offer these modules, and 99.9%, are directly
compatible (using 'clones' of the old Hitachi controller chip). Most
offer different pinout options. So (for instance), Powertip, offer the
'PC1602-H', with a 16 pin conector, or the 'PC1602-I', and the
'PC1602-J', both with a 14 pin DIL connector. Then you have versions
with 14, and 16 pin SIL connections, above, and below the display. In
many cases, the 14 pin version has been dropped, since you can just use
the lower 14 pins, and not connect to the top two pins, with the
seperate backlight connection at the other end of the board. Also some
of the newer modules offer a jumper/solder pad, to power the backlight
(only on LED backlit versions), from the 5v connection feeding the
logic. Some, have the 16pins, but don't bother to even make the upper
two connections. Have a talk to somebody like CrystalFontz, and they
should be able to do you a version of the CFAH1602, that runs from a
single power connection.

Best Wishes

Thanks for the info, very helpful! I will get in touch with CrystalFontz.

Dan

 

[Dan Nigrin]

Hi Dan,



Dysfunctional site, so I can't say anything on this one.


On most 16pin "industry standard" LCD modules pins 15 and 16 are more
or less directly connected to A and K you see on the right of that
picture.
Of course this only applies to LED backlights, not EL!


Sure. There must be A and K terminals then. Just wire them up, but
try a 470 ohm resistor in series first.


You can use any of these displays you can get, if it is same size
and character/lines number.
But take care: there is some sort of contrast control voltage
(V_lcd, pin 3).
Usually, this voltage is between 0 and +5 Volts.
Sometimes there are LCD modules which want a negative contrast voltage.
Mostly these are modules for an extended temperature range.
It is best to measure what voltage you have on pin 3 and then pick
a suitable replacement.

HTH
Wolfgang

Thanks for the information!

Dan