AT OC9 MLii channel problem


I have a Linn LP12 with a Jelco 750D arm.  I have a Dynavector 17D3, an AT OC9 MLii, and a Grado Gold 2 cartridge.

The Grado is too high compliance and doesn't pair well.  The Dynavector is very nice.  I went to try my OC9 and one of the channels is not playing.  

Could this be a headshell issue?  Or more likely a cartridge issue?

I would like suggestions for the OC9.  Send it to Audio Technica for repair?  Send it to Soundsmith?  Other thoughts?

Thank you.
sjackso1
Are you using the same headshell with the OC9 and the 17D3? If you are then it is a cartridge problem!
I am using a different headshell with the two cartridges.  The OC9 has a new Ortofon headshell, an SH-4.  The 17D3 has the Jelco headshell that came with the 750D tonearm.
Put the OC9 in the Jelco headshell. If it works then the problem is the Ortofon head shell. It can also be the headshell wires!
I have two ortofon sh-4 headshells.  I swapped the OC-9 to the other headshell which previously had the Grado Gold 2 cartridge mounted.  Both channels worked but the high compliance of the Grado was not a good match for the Jelco/LP12.  With the OC9 now mounted a known good headshell I am still missing a channel.

Now back to my original questions:
-  Send it to Audio Technica?
-  Send it to Soundsmith?
-  Other suggestions?

Thanks. 
Send it to Audio Technica. Most likely they will send you a replacement at no charge !
My opinion....

Appears to be a busted cart.  AT is pretty good at customer service when it comes to these kinds of problems / possible manufacturing or materials defect.  If the cartridge has some serious hours on it, then expect to pay for a trade-in.    

But stick with the OC9/II, don't be fooled by other manufacturer imitations.  The OC9/II is an excellent match for the Jelco SA-750D arm.  That is speaking from direct personal experience.