I don't foresee the 1HY being a problem (this controls K1/K2 and brake release supplies) depending on the signals provided to it by the 1HP.
FYI....
I've plumbed for the 1HP as this sits right in the middle of the complete process - however I am not convinced, but it is a logical step if you have one - considering:
--- TB2 Interface is connected directly here - CN1.
--- Operation Panel Switches are connected directly here - CN2.
--- 1HY trigger and K1/K2 check back signals - CN3.
--- Teach Pendant is connected directly here - CN4.
There are some small dipswitches and jumpers located on the 1HP, so make sure the replacement matches....
I've had a look and default settings for a standard 6 axis with no external or optional 1HP are:
DSW = 1,2,3 On and 4 Off.
JP1 = 1-2 and 4-5 shorted.
JP2 = 1A-2A and 1B and 2B shorted.
See how you get on, at least it'll remove it from the list of things to eliminate.......