Picked up the Pro One yesterday. Greg, the tech, said both ICs he replaced were to do with the gates/clocks etc. The Pro One works wonderfully, now, by the way.
When I dropped the synth off with him, I mentioned that something had come loose inside the synth as it made its way from Berlin to California. He showed me the part yesterday - a bit of the metal clasp from the suitcase used to transport the synth had broken off and had made its way into the synth from underneath the keybed!