Upgrading adventures from MK3S+ (and MMU3) to MK3.5  

Upgrading adventures from MK3S+ (and MMU3) to MK3.5

The day of the upgrade arrived I decided to dismount my nice MK3S+ with REVO & MMU3  to convert to MK3.5 with REVO (and update it from 40W to 60W) and MMU3.

The Prusa Knowledge base with assembly manual regarding MK3.5 and MMu3 is a mess. Now they have too many variants and mixes of devices and there are no clear manuals for all of them. I started searching for the MK3S+ to MK3.5 upgrade manual, but soon I realized that it covers a vanilla MK3S+ not modified for the MMU3. There were lots of steps not required, and some others completely obscure, like the statement that says that you may have a newer plate and the PTC replacement steps guide is not required.

- How to know if the PTC bed change is required or not ? I decided to do in any case, and I also noticed that they were different, so I assume it was required in my case.

Another mess was around upgrading the Buddy box: it was not immediate to know/remember  each wire coming from the extruder what is was.

In my case, since I had to upgrade also the REVO, I had to dismount the block of wires from the extruder, and this was the occasion to label the other side of the wires with sticker on the buddy box. There wasn't any picture on the manuals regarding the connected wires in the buddy, but the connectors were different, so I assume there were no mistakes.

There was no guide step to connect the MMU3 cable for the MK3.5 on the buddy box. I just guessed. Even on the MK4 manual for assembling the MMU3 it refers to the MK3S+.

On the MMU3 assembling manual for MK4 I found a new part I did not have on my MMU3 box! Looking better I discovered that all the MMU3 have been upgraded in April, and to have an updated MMU3 it would require a complete reprint and dismount and re-assembling!!!

I am re-printing now only the cover, since it has a strain pressure part that prevents the MMU3 daughter board to break, and that was not present in my version.

If the cover does not fit with the body, I will have two options: stay as now, with a floating MMU3 daughter board, or reprint and reassemble the whole MMU3 😨 

During the bed update,  dismounting the bed I found a bad surprise: the PCB connector copper squares where the screw are, seemed like corroded/plated and the copper is almost gone 😱  It is very thin.

so, I decided to tin the whole parts to give more areas for the power to flow and thick the level.

I should plan to replace the bed in the future.

Now reviewed the assembly and it seems fine.

I update the FW to the latest MK3.5.

I just discovered that the MMU3 is not working any more, it is like it is off. I should check the cabling and power. 😑 

I started the Setup test, and it is not passing the REVO check. 😰  I have the 60W Revo on.
It starts the test, it heats up to 290° and then I get the error message.

Regards