Fairlight-CMI

I'm helping out a friend who bought a malfunctioning IIx. Both drives don't work.

It took us a whole afternoon to figure this out. It shows a distorted image while trying to boot from the system disk. However it's possible to boot from the QDOS disk.

We swapped all the cards from my working unit with his unit but the result was always the same. 

The left drive is the least functioning one. You can hear its motor running when you insert a disk but it doesn't perform any read actions. You don't hear it's head clicking. Inserting a system disk in it will tell us that it's an unidentified system disk.

The right drive has a strange issue. And it was this that through us of when we were debugging the IIx. It will boot from a QDOS disk but it won't boot from a system disk. 
It starts to boot from the system disk. You can hear it click regularly for 5 times after which it stops. The screen will then show a random distorted image.

I see 2 options:

1. Repairing the drives. But I don't have any experience with this. So, does anyone have any experience that he/she wants to share?

2. Installing a HxC drive. But I don't have a clue how I would do this. I'd love to have some proper instructions to try this out.

David
http://dvdborn.blogspot.com