There are so many negative postings about the MMU that I thought I would post my relatively positive experience.
I have been using 3D printers almost daily for 6 years, and I can well understand the frustration of those for whom the MMU has proved a nightmare. There are simply too many variables to make it easy to give advice remotely.
With the MMU I think there are a number of vital variables which can be controlled....
1 ensure you are using filament which you KNOW prints well. The MMU will not cure filament problems and I have bought filament which has refused to print correctly after a whole days trying.
2 ensure a friction free path through the multiplexer for all four filaments. Remove it and push filament through. If it binds it won’t work.
3 check the pressure on the Drive gears, too little or too much and they will,slip and click. Use a gauge such as syrene strips to make them all the same.
4 start by printing a single colour with each filament, if this works continue, if it doesn’t find out why one or more don’t work
5 try different temperature
6 try a print with four small blocks, one of each colour. This will check out correct filament changing.
Finally I do feel,for,those of you having problems. Nothing worse than paying for something which is not working, but you do need to be methodical in trying to resolve things.