MP2550 folded corners when duplexing

[Iowatech]

I had a call on one of these for a noise. While it sounded like the developer mixer gears were worn out (and most likely when I changed the PCU the noise went away), as usual I also lubed the ends of the hot roller as that is the normal cause of most noises in machines with this type of fuser.
Unbeknownst to me, I probably accidentally broke the outer fin on the front side of fuser entrance guide. When I tested the machine, it was nice and quiet, but it folded the front leading edge corner on all LEF duplexed copies. When I found the broken fin, I filed off the stub and there were no more folded corners.
I hope this helps others, as it took me a while to figure out what was going on here.

[Mark Bbb]

Ah, finally someone with the same problem
It took me years to find out what was causing this.
Did you fit a PCU 1027?

[Iowatech]

Did you fit a PCU 1027?

Sure did. I've never had a problem with it.

[bob marley]

Thanks for the info.

[Mark Bbb]

Sure did. I've never had a problem with it.

That will be your problem: you must use the Original rebuilding pcu.
Don't ask me why, but the assembled pcu 1027 will cause the machine to jam with duplex!
When you have fit the pcu 1027, it will jam duplex, but after a while it will work fine, sometimes a very long while!
OK?
Greetings,
Mark

[Codex]

Thank you!!, had same problem months ago, and i did did the same