Are the hash cards interchangeable on the S9 miners with all of the different machine combinations?

Have 2 machines with some issues with hash boards ...one is a 12.3 ?? and one is a 13 or a 13.5 I think...

I assume the hash boards will interchange but will only hash at the rate they were designed for right?

I'd like to send a couple of boards off for repair.  Anyone know of a good place in the U.S. that will repair them?

Any idea on what they charge for repairs?  If it is to much for repair I'd be buying another new one..

Thoughts?

PS. I did just purchase a brand new s9 Antminer 13.5 on Bitmain for mid-april delivery for $755 (using BTH) which includes delivery.  I did use a coupon for $420 off though.. great deal if you can find the coupons!