Wasn't me, although mine was regularly subjected to 8-9 bar, once even 11 and it was actually a chinese clone of Mini express

I have no experience with E61 machines, but as far as I know, it has some kind of preinfusion system, consisting of several valves and springs built in, that delay rise of the pressure during first few seconds, even if it is set to more than 9bar. Is it possible something to be wrong with it ? {image}

Coffee with brand name DeLonghi could be Kimbo (at least it's sold that way in my country together with espresso machines), quite dark roast, and probably something like half a year post roast, it's not expected to produce something tasty

That's ok. Sorry for going off topic - my ranting about the design is very unlikely to improve things anyway ... As I said, from the videos posted by OP it looks like the link from the lever to the piston is turning a bit too hard around that join, as soon as it touches the plunger it displaces

It's indeed hard to say from his videos taken from that angle. Plunger obviously isn't engaged correctly on my screenshot from his video, but link anchoring point seems to be close to the middle of the cylinder, where it should be with plunger vertical and correctly engaged, so slight difference in ...

Thanks. This angle with lever about horizontal is quite small on your machine (so it is bigger to the other side at the very top and bottom, which is not a big problem) - plunger indeed has some tendency to tipple forward at the beginning - unlike on OP's machine, where this angle seems to be consid...

Yes, this never ending story of selling "improvements" to customers is well know to me. Microsoft has been doing similar for decades ... Problem is that design isn't ok. Somewhere in the middle of the pull link between lever and plunger is a few degrees from vertical, so that force to the plunger is...

By looking closeup action of this mechanism I would say it's a miracle that plunger is able to stay upright during the pull even with brand new machine

Interesting, that one is also thermoblock ... Never really looked at it, but I though it was a device with boiler

Seems to be a thermoblock device. Why is it so big then ?