Help with 1602 LCD please

Thread Starter

Bazinda

Joined Oct 17, 2019
1
Hi,

First time poster here

I need to replace a broken 1602 lcd with a new one. I’ve noticed that the connector to the lcd only uses the first 14 pins and not pins 15 and 16, but the backlight is always on. Is there a way which I can replicate that?

I know I can jump pin 1 and 2 to pins 15 and 16 but ideally I’d like to avoid that.

Here’s a picture of the original


C5D5BA5B-D72F-4457-B479-ECF5E8C182D1.jpeg


And here’s a picture of the replacement:

89A6BBFF-BF31-4E0A-B2B4-E7825C4FAACB.jpeg


Hope I make sense, I am a noob though.

Mod edit: thread title - JohnInTX
 
Last edited by a moderator:

MrChips

Joined Oct 2, 2009
19,415
Welcome to AAC!

It is not quite clear your situation.

The original LCD has how many pins, 14 or 16?
The replacement LCD has how many pins?

Sorry, I just saw the captions on the photos.
 

bertus

Joined Apr 5, 2008
20,104
Hello,

Looking at the first photo, the PCB shows 16, but there is a 14 pins header mounted.
The PCB in the second photo also has 16 on there.

Bertus
 

MrChips

Joined Oct 2, 2009
19,415
Pin-15 is anode.
Pin-16 is cathode.

Are these connected to A and K points on the LCD board?
What happens when you wire to A and K and ignore pin-15 and pin-16?
 

SamR

Joined Mar 19, 2019
1,297
It looks like there was a mismatch on the pins 1-16. The original board used 1-14 and the new board looks like it was attempted on pins 2-15?
 

AlbertHall

Joined Jun 4, 2014
8,540
I believe the jumpers J1 & J2 on the original board connect the backlight to power but there do not seem to be equivalent jumpers on the new display. You will need to wire them separately.
 

dendad

Joined Feb 20, 2016
3,084
Pin-15 is anode.
Pin-16 is cathode.

Are these connected to A and K points on the LCD board?
What happens when you wire to A and K and ignore pin-15 and pin-16?
Do not use A and K.
Use pins 15 to 5V, and 16 to 0V so the series resistor R8 is in circuit.
 

MrAl

Joined Jun 17, 2014
6,642
It looks like there was a mismatch on the pins 1-16. The original board used 1-14 and the new board looks like it was attempted on pins 2-15?
Hi,

I think that is an illusion the connector body plastic covers PC board pin hole 15 but the metal connector pins look like they go in board pin holes 1 to 14. Notice we can imagine another metal pin with the same pin spacing between the last visible metal pin and board hole 16 which would have been metal pin 15.

But i really think we should see the top side of both boards too. However it is probably true that the AK are hard wired on one board and not the other, so to duplicate the new board would have to be hard wired also making sure to have at least 1k between the power source and the LED connections AK.
 
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