Garbled text on LCD screen

[ytumer]

Hi all,

After updating my firmware from Repetier 0.91 to 0.92.2 the LCD screen text becomes garbled every now and again. The only way to get it to display correctly after this happens is to either repeatedly disconnect/connect Repetier Host until it decides to display correctly or turn the power off/on to the Rostock (which works first time, every time). This never happened on 0.91. I have tried recompiling and uploading the firmware to no avail. Any insight would be appreciated.

I'm not sure if it makes a difference but I have the older style ATX PSU. I think it was a 2014 kit (can't really remember).

This is what it looks like.

[IMBoring25]

Mine is also having LCD idiosyncracies since the firmware upgrade that it didn't have before. I have replaced the ATX with a basic PSU with a bonded negative. I think I've isolated it to when I touch something conductive on the machine, be it the towers, hot end, or the face of the LCD. It has not done it for me if I am very careful to touch only the knob itself on the LCD and to not touch anything else.

[MHZathras]

I have upgraded my v2 to v3 and added the HE280. This upgrade path introduced expansion the I2C bus to the print head assembly. This required the reallocation of existing wires run through the rear column. The Display Assembly also runs on the I2C bus internal on the Rambo board. Someone in one of these steams talked about noise on that bus. That could explain the possible corruption of the Display, as the general form of the displayed data form seems correct, just corrupted characters. Fer-rite beads would limit the upper bandwidth (and baud rate) of the cable. I am going to try setting a better ground on that aluminum extruded column base. When I have time I plan to drill/tap the bottom side, or somewhere and connect it to V- on the power supply. That would shield about half of the I2C bus from being a receiver of interference or a radiator .

[Eric]

I have upgraded my v2 to v3 and added the HE280. This upgrade path introduced expansion the I2C bus to the print head assembly. This required the reallocation of existing wires run through the rear column. The Display Assembly also runs on the I2C bus internal on the Rambo board. Someone in one of these steams talked about noise on that bus. That could explain the possible corruption of the Display, as the general form of the displayed data form seems correct, just corrupted characters. Fer-rite beads would limit the upper bandwidth (and baud rate) of the cable. I am going to try setting a better ground on that aluminum extruded column base. When I have time I plan to drill/tap the bottom side, or somewhere and connect it to V- on the power supply. That would shield about half of the I2C bus from being a receiver of interference or a radiator .

Someones been feeding you fairy tales. The LCD display portion of the control panel is a 4-bit parallel interface plus two control lines. All six of those lines connect directly to CPU pins on the Rambo. The I2C bus wasn't utilized at all in Rostocks until the HE280 came along.

[MHZathras]

I stand corrected. I assumed the display was an I2C device. I have another arduino system I built utilizing that bus for the display. So when I got a garbled screen and it cleared when I unplugged the I2C bus from the Rambo I assumed the bus contention. Thanks for clearing that up. I still occasionally get the garbage display now, but it usually clears after turning off the AC and back on.

[ytumer]

Thank you for all of your replies. Unfortunately I still haven't been able to address this issue.

I don't know much about firmware but is it possible that while upgrading the firmware one of the settings pertaining to the LCD display may have changed over the years that is specific to a different display? Do the new versions of the Max use the exact same one?

[obbears]

Is there a permanent solution to this? I'm getting this everytime I turn on my V2 and only way to clear it up is to disconnect and reconnect in MatterControl.

[geneb]

Have you contacted support about it?

g.