1.24 sync problem

Hi all. I have two mpc2500's. One has 1.23 & the other 1.24.
I use the 1.23 as my sync master with other various groove boxes and everything works fine.
When I change things about to use the 1.24 as the master there is a massive delay with midi timing and sync. I am using the same leads and sure I have checked the obvious .
Any thoughts greatly welcome ..

I dont know if this will solve your problem but why not try the free JJ´OS 3.10 ?

Children are starving and you sit with TWO mpc2500!! shame on you!
good luck