Swap LCD -> OLED for troubleshooting
Afternoon everyone. I woke up to my MINI+ locked with a white screen and an enormous spaghetti mess from a Z-shift failure ~8.5 hours into a 10 hour print. 😵
TL;DR - if my LCD screen and/or cable are solid white/bad, can I match up pins and connect a small OLED for troubleshooting and emergency operation?
The LCD screen is solid white and the printer was completely unresponsive to the knob. (I later found the knob does work - I have the buzzer turned off and didn’t realize I was “clicking”.)
I reset the printer, still white screen. Then I:
- Cycled power
- Unplugged for several minutes
- Removed USB and Ethernet
- Reseated LCD cable (both ends)
- Swapped LCD cable ends (between board & display)
- Re-flattened LCD cable
- Reconnected Ethernet, found PrusaLink still connects and uploads (hopefully narrowed to bad LCD and/or cable, not main board)
- Attempted print via PrusaLink, printer heats but stops with “Attention” status in PrusaLink (wrong filament warning, I think)
- Loaded newest firmware and attempted flash (using blind knob clicks from flash instructions). Don’t know if it flashed, but no help.
Occasionally a badly distorted, upside-down “Prusa” boot screen shows when booting (I’ll try to load a snapshot of it soon.)
I see the parts are relatively inexpensive, but I’m in the middle of some time-sensitive prints and also can’t afford to spend money on unnecessary parts.
Had a crazy idea: I have a 5V OLED for an arduino project, and in just crazy/dangerous enough to see there are proper display out pins from the MINI to connect the OLED with a breadboard and some jumpers.
I’m also halfway smart enough to know it’s probably not that simple, with different display types and resolutions and all.
Before I fry my MINI or my OLED, can anyone speak from experience or knowledge that I don’t have?
I’d also gratefully accept any other troubleshooting advice!
RE: Swap LCD -> OLED for troubleshooting
In short - don't do this.
You could try to disassemble existing cable and cutting the existing fragemeents but it would make cable shorter so it may not be possible to keep it in the same place as it used to be (but at least it would be useable!). Currently I would rather try to replace the cable with a new one (or old IDE disks with 40 wires) and new FC14P connectors.
Regarding OLED - you would have to have the OLED controller that speaks the same protocol that LCD uses, which may not be that easy. There are differences in the signal timing, protocol, resolution and refresh rates, voltages and so on.
Alternatively you could switch to external system such as Raspberry Pi and connect the device over USB cable to the mini-USB port on the printer and used something like OctoPrint to manage it. https://help.prusa3d.com/product/mini/octoprint_249
See my GitHub and printables.com for some 3d stuff that you may like.
RE: Swap LCD -> OLED for troubleshooting
Thanks for the reply!
"differences in the signal timing, protocol, resolution and refresh rates, voltages and so on"
Compatibility issues... that's what was tumbling around in my head. Thanks for helping me put a finger on what I was generally thinking, without the actual knowledge you have. 🙂
And for the cable, I didn't explain my thought very well. I was going to use male/male jumper wires to connect the ribbon coming off the main/buddy board to a breadboard the OLED was inserted into. Kinda hare-brained, perhaps, but I thought it was a functional way to convert and connect a 14-wire IDC to a 7-pin header. 😉
I'll just scrap this idea and move on to sourcing replacement parts for the LCD cable and screen. Thanks for your tine and help!