Well of course not, but I just had to post the picture Got the stereo decoder working in my other 900K, too...
I do have a question as well, though - what is the third speaker connection marked "+EKS"? I can see from the schematic that it's just an unswitched clone of the left speaker output, but what is the purpose for that?
Does anyone have the complete service manual (hopefully to be added on the site)? I have the schematic and some kind of a third party service bulletin I found on the net, but the quality is rather poor...