Help to find part -Replacement LCD

jpanhalt

Joined Jan 18, 2008
11,087
The number on the back suggests a 16x4 (4 lines of 16 characters), but the 18 pins is a bit unusual in my experience. The parallel interfaced ones I have seen had 16 pins.
 

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Bryston

Joined Dec 27, 2018
4
How can you tell a character from graphic? It display character when it’s on.
Here is what it looks like. Thanks

7329B2A9-60BF-44B0-8702-FA4166D43F72.png
 
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jpanhalt

Joined Jan 18, 2008
11,087
These additions:
upload_2018-12-28_6-10-14.png upload_2018-12-28_6-13-18.png

might suggest a graphical display, but that is far from certain. Even with character displays, one can create special characters. The fact that the display shows only 3 lines and the bottom line has more than 16 characters is also suggestive of a graphical display. Moreover, the homogeneous background is suggestive of a graphical display. Character displays will show darkened boxes for each character if the contrast is turned up. It may also be a special display for that device. If you have access to the code, that would help, but I suspect you do not have that access.

Just found this example of a 122x32 graphical display: http://www.newhavendisplay.com/specs/NHD-12232AZ-FSW-GBW.pdf . Its connector has 18 pins.

The display size is often indicated in the part number. For example, 16x4 character displays will often have "1604" in the part number. Your display has 1604 in its part number. But, it also has "12232" in its part number. All told, I am leaning toward a 122x32 graphical display.
 

Externet

Joined Nov 29, 2005
2,232
Usually the 2 'extra' pins are for displays with backlight built-in.
These are very standard, but do not remember seeing 3 lines; if that last picture corresponds to the display in question.
I do have several spares, but 16x1, 16x2 if you are in USA.
Make sure how many lines and characters is it, and search for it.
Example: for 16x4:
----> https://www.ebay.com/sch/i.html?_nkw=16x4 lcd
 

jpanhalt

Joined Jan 18, 2008
11,087
The TS's display shows 3 lines of fairly large characters; one line has 20 characters.

The 2 additional pins, compared to a character display, for the graphical display I linked to are for "register select" (data or command) and the equivalent of chip select (there are two controllers on board). Character displays typically use bit <7> of the serial data lines to denote a command (bit 7 = 1) or acsii character (bit 7=0). Graphical displays cannot depend on an ascii (or small number of special characters) to be sent. That switching can also be done with 2 bytes (e.g., the SparkFun 4x20 character display uses 2 bytes).
 

dendad

Joined Feb 20, 2016
4,494
You will have to measure the original and the replacement to see about that.
And it may be a hot melt glue mounting option too.
Have you got he replacement data sheet? It will have the dimensions there.
 

jpanhalt

Joined Jan 18, 2008
11,087
As pointed out before, the pinouts for LCD displays are fairly standard. Character displays seem to be more standardized than graphical displays. If you compare the display I linked to with the one you linked to, the pinouts are different. For example, pins 17 and 18 on the New Haven display are for the LCD backlight. On the display you show, they are for data.

Since your current display is apparently trash, you could test it to find which pins are for the LED backlight. Both displays use LED's for that, and LED's test as ordinary diodes. Apply a voltage thought a resistor (say 1K) to be absolutely sure. That will be helpful in selecting the correct replacement. The other difference I have seen is how Vo is supplied. LCD displays need a negative voltage. Many displays generate that voltage on boards, but some do not. You can verify which pin is Vo using a voltmeter.

In other words, if you can identify the power pins (Vdd, Vss, Vo, LED+, and LED-) and they line up to what your device has, then the rest will probably match up too. You will also need to know whether the supply voltage is 3.3V or 5V. Find that by measuring the source.
 
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