Glad no one got hurt. I had a cylinder blow up in 01 on a 32 Z, They were making them out off fiberglass with a steel liner.The bolts failed to keep it together.Probably a bad weld.

Do you strap your boom?

If it snapped first,my guess the clevis pin siezed causing the weld to fail,a twisting motion.

an uneducated opinion

I have never seen a rod being bend like that, they usually snap; seems like something wrong with the material used for the rod, too soft

It's unusual to strap the boom in Europe , I have never seen a pump with a boomstrap , not on the BAUMA fair has Putz Schwing Waitzinger Saraka you name them a boomstrap on the pumps . I saw it first in ACPA safetyvideo and in World of Concrete fair . You tie the boom to the pumpchassi with a strap .

looks like the pivot where the pushrod is connected to is blocked by lack of grease in some kind of way

We strap the boom to prevent it from bouncing around the cradle while driving.Not natural for a boom to be bouncing around the rest,natural for a boom to be waving through the air.

I've seen this twice both on the same pump different cylinders once the tip section and then the 3rd section all pumps were very well maintained, this is another circumstance when these booms are inspected some type of UT testing or xrays on certain parts is becoming neccesary, we will never be able to stop machinery from breaking but if there was a way to check the pivoting points , tower structure , and your concerned areas on these booms it may catch some problems before they become catastrophes, seems as though within the first year of operation a manufacturer would randomly check pieces of equipment then after that boom inspection should require this bi-annually , I know this will add expense but its hard to put a pricetag on the mens lives that stand under that boom every job , just my opinion , nothing else. 

So, where is a JMBH manufactured?

JMBH used to be a Korean KCP pump. About 3 or 4 years ago they started manufacturing their own pumps in Korea. I visited their factory and they seemed to have a good build quality.

I was wondering about that. (sure looks like a Putz/Jun Jin/KCP)

Putz sure has created a lot of concrete pump manufacturers with their contracting out manufacturing.  At least that's how I see it.  Then the Koreans have no qualms about stealing plans, technology and people and branching out.

Now Putz is doing the same thing in India??  I wonder how this will turn out?

An abstract view,anything for a buck.

Nothing is immune to gravity, except for, maybe - antimatter. What goes up, must come down, doesn't matter what name is stamped on it.

it does not matter which brand most have common components, also metal fatigue, imperfections in the casting process, overheating the steel when welding or machining is common not to mention lack of maintenance or overloading the boom could all be issues, my thinking is dipstick will let us know.