Not familiar with the brand but on a Putz you can adjust the valve reaction for initial stick movement and full stick movement.  Then, the proprtional band is figured by the computer to evenly move the valve within that range.

Can you set the initial stick movement?

JMBH WHERE DOES IT COME FROM.

Ha..."Don't touch it!  That's what we use when we charge you for a service call!"

Sounds like a bolt on the stack valves?  Can you post some pics?

Try www.concretepumps.be, they sell that brand of pump.

Send Kris Leers  a mail he sels these pumps

What is the pressure at the stack valves? Is it at specs??

Stack valves are the valves where the handles are on the truck as you called them in your first post.
But I would rather check the valves on the cylinders, don't remember the english word right now, saturday and all things right now... :D

Pilot pressure on your check valves? Makes sense?

As you said in the first post, that the levers moves as soon as you move the stick on the remote, but the cylinders on the boom doesn't.
This makes me think that the pilot pressure is set a bit too high, so you have to build up a lot of pressure before they opens and the cylinders get fluid and start moving.
A setup like this is good for black-white remotes, not so good with proportional remotes.
If you adjust the preset pilot pressure down a bit they wil open sooner and flow oil to the cylinders.
Just a thought from me, we had to do this with a Cifa when we could'nt get it setup like we wanted with the remote and electronics only, so we got a Cifa mechanic to adjust the pilot pressure.

We would have done it ourselves if it wasn't still under warranty.

I got a mail from Dipstick and explained him how to adjust it.

It is indeed like 52PUTZ says the adjustment of the radio controll.

Just like Putz the JMBH has got a HBC radiocontroll. You can adjust the valve reaction for initial stick movement and full stick movement.