Jca,
Your PC78-6 or PC78-8 should have a pattern control changer as standard equipment. The changer is located in the small compartment door on the left side of the machine just below the cab door. Simply back out the lock nut, switch the lever to whichever position you want (SAE=Backhoe, ISO= Excavator) and lock down the lock nut. This is a 5 minute operation, tops.
Hope this helps. Let us know how you make out.
Best,
Tony