LCD Display of Same Specification doesn't work

[Electrical_Shocker]

I have replaced a Newhaven LCD Display Part Number -
NHD-0216XZ-FSW-GBW with the Hantronix display HDM16216L-5-Z1BS. The specifications look the same. Any idea why they wont work ?

 

[BobK]

What do you have on pin 3, which is usually a pot to adjust for contrast? If you have put a fixed voltage, the new display may need a different voltage.

Bob

 

[Electrical_Shocker]

I'm getting blocks and not the characters and the backlight. Will it be because of the voltage?

 

[Harald Kapp]

Likely. The blocks can appear when contrast is too high so that even a light pixel becomes dark.

 

[BobK]

Yes. If you answer my question, I might be able to help.

So, let me re-phrase it.

What is pin 3 connected to?

Bob

 

[Electrical_Shocker]

Here is the schematic . . Please help me how should I reduce the voltage?

 

[Electrical_Shocker]

Yes. If you answer my question, I might be able to help.

So, let me re-phrase it.

What is pin 3 connected to?

Bob

 

[Electrical_Shocker]

So I tried changing Voltage across pin 3. It only changes contrast of the blocks that are displayed. Doesn't show any characters still.

 

[BobK]

OK, that rules out the contrast issue.

Bob

 

[Electrical_Shocker]

Any idea of Why I am getting blocks and not the characters?

 

[BobK]

Normally, that means initialization has not succeeded. If you are not using the busy bit, increasing delays a bit might help.

Bob

 

[Electrical_Shocker]

I just have a hex file for this micrcontroller. Is it possible to change delay in a hex file?

 

[BobK]

Not without reverse engineering.

I suggest you try to find the exact replacement if you do not have the code.

Bob

 

[Electrical_Shocker]

I thought the Newhaven is the exact replacement. Any suggestion which one would be the exact replacement to the Hantronix one? . Thank You for response.

 

[Electrical_Shocker]

Replaced LCD part number
Newhaven NHD-0216XZ-FSW-GBW with the Hantronix display HDM16216L-5-Z1BS. The specification are the same but this gives me blocks as output on LCD screen.
I also tried the Lumex LCM-S01602DSF/A display but again the result is the same.
I am using microchip PIC16F627A microntroller for this. As this is a old program I only have assembly language (.asm) and .hex file for this. .hex was the original file. I somehow converted it to .asm using mplab.
Any suggestions guys?

 

[JWHassler]

Read this for some notes