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Rebuilt extruder and now it won't boot!  

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gnat
 gnat
(@gnat)
Noble Member
Rebuilt extruder and now it won't boot!

Originally it was a MK3, I upgraded it to a MK3S/MMU2S, 1.25 years ago I upgraded to Bondtech's extruder, 1 year ago I removed the MMU2S, last week I got a jam so bad I had to tear down the hotend. Leading up to the jam it had been printing 0.1mm layer prints pretty much non-stop for a bit over a month straight. This is the first time I've had to take the extruder apart since I installed it.

While I was in there I finally replaced my noisy part fan that has been driving me nuts for the last 10+ months (knew I should have gone ahead and replaced it when I installed the Bondtech, but I was in a hurry...) and I found the red covering had been abraded through on one of the heater leads (inner insulation was still fine) so I replaced the heater and thermoresistor.

Everything is back together and I've double checked all the wiring, but the printer does not boot when I power it on. A green LED at the top of the board lights up and the LED on the PINDA lights up, but the LCD does not light up and the fans do not perform their self check. I have previously messed up the order of the LCD ribbon cables and it acted similar, but after the last time I marked them so I know they are plugged in correctly this time. I just opened it back up and triple checked all my connections against https://help.prusa3d.com/en/guide/4-electronics-assembly_193383

Anyone have any ideas what the issue might be or what else I can check?

Best Answer by gnat:

So apparently it helps if you correctly remember the meaning of the markings you made to help remember which cable goes in which port...

After unplugging everything and starting to check all the wires with my multimeter, I decided to try swapping the LCD cables anyway. Turns out the problem was exactly like when I previously messed up those connections because I did it again 🙄 

MMU tips and troubleshooting
Posted : 02/08/2021 8:10 pm
Diem
 Diem
(@diem)
Illustrious Member

Repeated (un)plugging does eventually impact the plugs...

Go through the connectors again, both ends, and make certain you have not bent or broken a pin in the process.  Check the continuity (multimeter) of each line in case you have strained/broken a wire somewhere.

Cheerio,

 

Posted : 03/08/2021 9:29 am
gnat
 gnat
(@gnat)
Noble Member
Topic starter answered:

So apparently it helps if you correctly remember the meaning of the markings you made to help remember which cable goes in which port...

After unplugging everything and starting to check all the wires with my multimeter, I decided to try swapping the LCD cables anyway. Turns out the problem was exactly like when I previously messed up those connections because I did it again 🙄 

MMU tips and troubleshooting
Posted : 04/08/2021 8:58 pm
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