Best replacement for an X30 AP? Also a troubleshooting discussion

[exitstrategy]

TL;DR
I believe that my Raymarine X30 Autopilot course computer needs to be replaced after I likely fried it by having two power sources on the network. But I see that it is no longer in current production. What computer is a drop in replacement? Or do I need to buy a new package including a new fluxgate and control head? Such as an EV-400?

Discussion:
I have a 2012 Lagoon 450 (#161) that had factory installed a Raymarine system including Depth/Speed, GPS, VHF/AIS, Wind, and RADAR. For displays at the nav station we have an i70 MFD, and a E120W Chart-plotter, and upstairs at the flybridge we have 2 i70 MFDs, 1 p70 Autopilot control head (no chart-plotter at the flybridge).

The system worked well enough for the first 5 years (except the wind instrument kept having intermittent problems with wind angle).

This summer I decided that I would like to expand the network to support NMEA 2000 devices so that I could transmit my AIS via the VesperMarine AIS device, and to broadcast the ship's data across our wifi network via iKommunicate's Digital Yacht and a wireless router.

When I installed the NMEA2000 devices I did not yet have a STNG to 2000 cross over cable, so I initially installed them as two separate networks. After waiting a number of weeks, the cross over cable arrived, and I connected the two networks. At anchor everything worked fine, and I was excited to see my ship's data on all the smart phones and laptops.

Three weeks later after the 3rd time we moved the boat, the p70 autopilot control head would report various error messages: No Control Head, No Pilot. Turning off and on would sometimes restart the AP. On our last voyage, we could no longer get it to work by turning on and off, so we turned off the p70 and had steered home.

As we steered home, all of the other raymarine instrument data stopped being displayed on any of the i70 MFDs. The GPS and AIS data from the VesperMarine unit on the 2000 was still working fine.

Troubleshooting at the mooring here is what I have learned:
First thing I did is take out the cross-over cable from 2000 network to the Raymarine network and operated them as two separate networks. 2000 worked fine. Raymarine – no data from any instrument.

The p70 AP control head refuses to turn on. It even passes power through a daisy-chain to an i70, but it will not turn on.

One of the i70s now also refuses to turn on < this was a very new development at the end of my trouble-shooting

I tried disconnecting and re-connecting all of the raymarine instruments one-by-one, none of that altered the behavior of no data on the network.

The only instrument that I had not yet disconnected was the X30 as it is also the source of power for the Raymarine network.

So I disconnected the X30 from the Raymarine network – and of course it went dead without power. Then I re-connected the 2000 network which does have its own power, and boom! All of the Raymarine data was back and being displayed on the i70s and the Chart-plotter.

Summary:
So, I think I must have damaged my X30 when I had power from the 2000 side mixing in with the power that the X30 was supplying. From that I think I killed the X30? Does that seem correct? Anything I can do to verify that the X30 is toast?

Similarly, I believe that the p70 was also damaged from the two sources of power, and probably that one i70 that does not power up any longer.

Solutions?

I need to buy an power isolating cross-over cable? Or be extremely careful and only turn on one source of power for the navigation going forward?

I have already ordered a new p70 control head, looks like I need to buy another i70 MFD.

But now I need to order a replacement for the X30. What does Raymarine suggest to replace the X30? The Lagoon 450 is a 30,000# 45 foot catamaran - the EV400? . (During the past 5 years, I had to often put the response level down to 2 or 3 or it would trip the current limit, do not know if the old system was slightly under-powered?)