Zenmuse H3-D2 not showing up in assistant

[Panteradon]

I have a Phantom 1 with Zenmuse H3-D2. With the Gopro mounted, i get power to the gopro, but the gimbal does nothing. It does not show up in the assistant software.

I checked wiring of the PMU an Zenmuse and it looks right.

Any thoughts on narrowing down the problem?

Don