The older UM2's the led strip is like a flexible silicon one. The newer ones is like a thin alloy strip with the actual leds exposed.
For some of the machines the black sections of the hot end bearing assembly is different but not sure of the lengths at from what time they changed.
The main electronic board has different versions so you could check those numbers.
Newer UM2's have a metal ring in the entry of the feeder and older ones don't.
There are a few other minor things but can't remember then right now.
Recommended Posts
IRobertI 521
No, the LED strip can't be used to date a machine. I'm guessing your friend is gauging it by the LED strip being covered in silicone or not. That has flip flopped back and forth a bit so it's not a good indicator.
The spacers are a better indication. The one with spacers is older. You'll likely also see that the bottom plastic piece of the head is taller than on the other machine.
The best way is to simply look at the serial number. They go in order.
Link to post
Share on other sites