16x2 lcd problem.any help appreciated.

Other Hardware Displays
1

Recently,I salvaged a couple of 16x2 lcds from some old printers but I have a problem.I tried to use them in my project but both had the same issue.As you can see in the picture,I can't get them to print what I want.I tried with another screen and I didn't encountered any issues.I tried to connect only the ground,the vcc and the pot but nothing changes.The model number is PC-16021C7-2A.btw, on the original board they were soldered,they were connected to the oki bu6152s chip.

Can anyone help me?

2

OK, so it seems you have two displays that both look exactly as you illustrate when reliably connected to a test rig in which "normal" 1602 modules display perfectly.

That given, there is no obvious answer. What you illustrate suggests either a fault - which is rather unlikely to be identically present in both displays, or a peculiarity of design requiring a quite different initialisation sequence.

Frankly, that is about all that can be said.