New RepRap Discount Smart Controller blinks and beeps, but doesn't display Main board: MKS GEN L V1.4
The SD card reader on the original controller LCD (from four years ago, or so) went out, so I replaced it with a touch screen. I found, however, that I don't like the touchscreen interface as much as the LCD home screen, so I ordered what I thought was an identical LCD controller. They certainly look the same.
The original controller is plugged in now and working. It should just be a matter of the EXP1 and EXP2 cables between new and old, but when I plug it in and fire up the printer, the beeper starts a constant, weak beeping, the screen sort of flashes on/off, on/off... Is there something I'm missing? Some fundamental difference between the old LCDs and the new? Is there firmware I'm missing?
EDIT: I saw this post that talks about turning the slots, but they don't move and I'm afraid of applying too much pressure. How hard should it be? Can I accomplish the same thing by reversing the connector on one end of the ribbon cable?
So, the answer in the other referenced post was correct, the slots were turned opposite how they should have been. AND YES: you can create a &quot;crossover&quot; ribbon cable and everything works great, so physically turning the slots is not necessary.