Problem with onne of my V4HD units

First off, it's been awhile since I logged onto the Cow, and I'm thrilled to find a V4HD forum here, and with the most helpful MOTU V4 tech hosting. Dave Roberts has been a terrific help via phone support in the past when I was integrating several V3's and then V4s into my business.

Dave,

Setting up for a recording session today (thankfully a set up day only) I couldn't get one of my V4s to get video onto my Mac. The signal is coming in via HD-SDI, and all I get in MOTU Video Setup preview mode is a full raster of hash. Within Final Cut, nothing. The log and capture record mode reports 'No Video'.

I do see the embedded audio on the V4's meters, but not in Final Cut. Timecode is coming via another route, not embedded.

The V4 does correctly report 1080, 29.97, and the genlock light is solid, both on the unit, and in the software.

I swapped video feeds with the one unit that was working.
I swapped laptops.
I tried new Firewire 800 cables.
I went through settings over and over again.
I restored the 1.04 Firmware.
I reset to Factory Default.

With all combinations, that one V4 unit was always in the combination that did not work, the other unit always worked. I think I've done my due diligence and narrowed the problem to that box.

I did not get to try with other types of input feeds, only HD-SDI.

Thankfully, I have a loaner unit arriving tomorrow morning (Thank you Sandor!) but would love to know if you have any thoughts of something else to try before I have to send the unit in for service. I have a job next week out of town that requires both of my record chains, so don't really have time to have it serviced.

Thanks for being here on the COW,

David