No Loop Sync Between 2 HD I/Os

[bitranarizpe]

Hey everyone,

So I've had this problem ever since I got these 2 boxes a year ago and I really want to fix it... My two HD I/O 16x16 analog have never been able to sync via loop sync. I've tried everything, switching digilink cables, buying new ones, connecting them in all possible configurations (both to the HD Native card, or via each interface's expansion port), switching BNC cables... And nothing. I can set one or the other as loop master, but I've never seen the loop sync light turn on, and pro tools doesn't play. Digitest shows no problems.

The only way I can get them to work is by setting #2 to output wordclock, setting #1 to sync to External Word Clock, connecting it to #2's WC out with a single BNC cable, and making #1 loop master. But this sometimes gets reset and it's annoying to have to set up everytime, plus it's a bit messy.

Has anyone encountered this problem before? Could one of my interfaces' loop sync ports be damaged? I really don't know what to try anymore. Any thoughts?

Thanks in advance

OSX 10.10.5 (Yosemite)
HD Native PCI
Pro Tools HD 12.7.1 (HD Driver 12.7.1)

[panamajack]

You are running Sierra 10.12.5? Signature says 10.0.5...

...and you have 75 ohm cables forming a complete loop? Loop Sync Out to Loop Sync in -- in both directions from each unit in the loop?

[bitranarizpe]

My bad! I meant 10.10.5, Yosemite. I've edited the post.

Yes, I'm running two 75 ohm cables in both directions from Out to In. I use the same cables for WC with no problems. I've also tried a few different ones.

[Dan IceWood]

I have had a unit that had the same issue, turns out that the loop sync cable inside the chassis needs replacing - super easy to do.

Just open up the lid, remove the ad/da cards and check the cable connection to the BNC connecters and then follow the cables to the other end which use a Wago style connector.

otherwise have a service engineers do it - shouldn't cost more than 100