What do I have??  

RE: What do I have??

This is the firmware version running on my MK3s/MMU2S

RE: What do I have??

Next, here is a video of the first loading after powering up. I have filament in slot 2 (already in loading position, therefor it triggers very quickly). It starts with idler homing and selctor homing (this is only done at first loading after power up), moves the selector to slot 2 and the pulley motor starts moving the filament into the selector. The additional green LED on the left shows the FINDA state and you can see it triggering. Now the pulley motot pulls the filament back to loading position and the loading is done. Slot2 is ready to use.

SelectorHomingAndLoadingSlot2 - 1

RE: What do I have??

Trying again using the same procedure you describe.

RE: What do I have??

AAAANNNNNDDDDD nothing attached, even though a long string of file parameters appeared in this window.

Trying one last time with a .ZIP file.

MMU Power-up

RE:

That worked...

Ok, your MMU's power-up sequence seems to include the selector homing. Might just be a different firmware version. The result looks ok. Can you move the selector by shortly (not to shortly) pressing the right and left button on the MMU? Does it move and does the corresponding LED show the position? Move the selctor to slot 2. Now, what happens if you select "Load filament" and "Filament 1" from the LCD menu. Does it move to 1 and does it try to load? What if you feed filament in that moment, does the MMU grab it?

RE:

Will check your questions later today, but does it make sense that once the MMU finishes booting, the first LED turns green without a filament being loaded? Does green just mean it is "ready" for loading?

RE: What do I have??

Well, the LEDs and their meaning depend on the mode/state, the MMU is in, they kind of make sense once you understand how that thing works.

First thing to understand: The thing is dumb as hell, it does not know shit and it does not care.

After power-up the green LED just indicates the current selector position - if there is filament in the slot or even ready to load filament: it does not know (how should it, there is no sensor for that) and does not care. If there is no filament and you instruct it to load (via button, LCD or GCode) it will fail, complain about it (red LED, LCD menu) and call it your problem, if there is filament in loading position, it will load it and waste no thaught about where that came from and continue it's dumb work...

If you understand that and learn to work with it, the MMU2s can be a very realiable filament changer and work for hundreds of tool changes without problem.

RE: What do I have??

The attached (and zipped) PDF may shed some light on the LED and button states of the MMU.

RE: What do I have??

Some progress but not much. After much fiddling I am able to get all five filaments loaded into the MMU. I can even then selectively advance a specific filament to the (heated) nozzle, but then, all printing fails with the appearance of under-extruding which I am attributing to high friction of the filament within the PTFE tube(s). Some more parameters have come to light (I was not scrolling far enough in the Support sub-menu.) I now see the entry "EINSy_10a", "E3Dv6full", and "Date: Dec 19 2018". Then "MMU2 Connected", "FW: 0.9.0-86". Removing a filament then becomes a crapshoot, frequently requiring a reboot/reset. When a filament is loaded to the nozzle, what is the difference between menu choices "Unload filament" and "Eject filament"?

If I load a single filament directly into the Extruder (not through the MMU) and then try to print something, I will, every time, get an "Upgrade Available" pop-up warning. Remember the machine is currently on FW 3.5.1-1778. Sometimes this pop-up will give the upgrade number as 3.13.1 and sometimes as 3.13.2. Again at this time, should I attempt to upgrade the machine? The MMU? Both? 

RE: What do I have??

The firmware update available popups are generated by gcode, take a look at the printer specific gcode in slicer an search for M115.
If you remove this line (from slicer pinter profile and/or directly from the (older) gcode files you print) the popups will be gone.

My personal opinion is:

Do not update the printer higher than 3.11.0 ( get it here: https://help.prusa3d.com/downloads/mk3/firmware ) Above that you will get the new thermal model that might result in problems if your hotend has been modyfied in any way, if you go much higher you will need to use the 3.something firmware for the MMU (see below).

Do not update the MMU higher than 1.0.6 (get it here: https://github.com/prusa3d/MM-control-01/releases/tag/v1.0.6 ) Above that you will need the printer on current firmware for the MMU to run at all)

Then, reduce the friction in your setup (buffer, PTFE, PTFE couplings ect) until you get it printing reliably, if you encounter the 5 LED blinking error, upgrade the powersupply (DIY or with the new PCB, there are cheap clones that do the job). If you sorted that out, upgrade to the current firmware and deal with the problems they add and enjoy the features they bring... or don't.