Display lights but no characters, just squares

[MHZathras]

I have a V2 machine that has been upgraded with HE280. All listed upgrades were done successfully months ago. I have also implemented an Aux 24vdc supply and SSW for the bed. Works great heats to 110C in less than 4 minutes. A few days ago the machine was warming the extruder to 245C and I lost all lights, only heard the supply fans still up. F3 was open. Ordered and installed today. I only get 2 rows of square blocks now. I can run the machine from MatterControl, no problem. I have replacement display and cables, it did not resolve. I need advice and a pointer to the schematic for the display and adapter board. I have the Rambo board schematic. I have my scope out I need to understand the circuits.

Thanks for any help in advance
MHZathras

[Mac The Knife]

I've had the same thing happen when I didn't have the cables plugged back into the display correctly.

[MHZathras]

Thanks, but I marked the cable/plugs years ago so I would not do that.

[brianmichalk]

I am having the same problem. I've been printing for over a year, and today the display won't work. I re-flashed the Rambo, and reseated all cables. I can print from Mattercontrol.

[rootboy]

Square blocks sounds like a problem with your contrast control. Check that first.