Trouble with replacing HD44780 16x2 LCD with VFD

[Mp3]

Hi all,

I have replaced many old non backlit or just worn out HD44780 on some older gear (Intel 8031 powered) with the $2-3 ones you can get from China. The cheap ones always work perfectly for me when replacing old 44780... this time I decided to get a little fancier and order a Noritake CU16025ECPB-W1J VFD as it says it's 44780 compatible.

The only problem is.... it doesn't light up when I plug it in! I'm sure I have it wired right because either the original LCD or one of the China LCDs which i've soldered to a 2x7 IDC ribbon lead works just fine.

Is there any chance the power supply might be too slow to get the display to reset itself and maybe that is the issue? I was going thru the datasheets to try and find what could be the cause. I've triple checked my wiring and checked every lead for continuity, etc, so i don't think my soldering is the problem here.

Datasheet https://media.digikey.com/pdf/Data Sheets/Noritake PDFs/CU16025ECPB-W1J.pdf

Many thanks in advance to anyone who might have an idea what is going on here and why this VFD isn't cooperating as easily as the $2 44780-compatibles i've been buying.

(Service manual for the device i'm trying to install it into if anyone cares: www.warningwillrobinson.com.au/manuals/Alesis%20MMT8_Service_Manual.pdf)
(Datasheet for the cheapo 44780 compatibles https://www.buydisplay.com/download/ic/SPLC780.pdf)

[danadak]

Many VFD modules have a self test mode that can be forced with a pin on
power up, does this one have a jumper to do this ? So you can verify if
VFD is working.


Regards, Dana.

[Mp3]

Many VFD modules have a self test mode that can be forced with a pin on
power up, does this one have a jumper to do this ? So you can verify if
VFD is working.


Regards, Dana.

Great idea, thanks a bunch Dana!

I found on this manual how to set the self test mode, shorted those jumpers and sure enough saw dancing snowflakes on screen 

http://www.oflittleinterest.com/VFD/CU16025ecpb-w6j_e00.pdf

Now just to figure out how to get it to show the letters I want. I will sleep on it and hopefully have a revelation later about it. 

(I did notice it expects a command to let it know if it should be operating in 4 bit or 8 bit mode. I'm not sure if my device tells the screen that info.)