ex120-2 boom slow

hi guys i got some trouble on this excavator hitachi EX120-2. The only slow fonction is the boom up and down,
fuse ok
pilot 700psi
pilot sensor changed with the other one
wire changed too
relief valve changed with another one
selenoid valve on the pump changed with the ohter one
tried to change the hoses with another fonction but the problem stay at the same place boom up and down
Spool is good too,
All fonction work good but not for the boom fonction, any ideas? thank you