Stahl-tek Vekian - help please!

I have a Stahl-tek Vekian DAC which has hit a problem. The guy trying to fix it for me is "flying blind" with no circuit diagrams or anything to guide him. Does anyone know where he can access some technical data to help fix the problem? (basically a crackle and hiss emerging from the right output channel)

There is a Facebook page but no apparent activity on it to help, so any suggexstions gratefully received....
roncalvert, the tech is just going to have to fly blind. It could be something simple like a bad solder joint or connector. At this point you have nothing to lose.
Yes, he is doing his best, but no luck so far. 

Thanks chayro, I shall try to get in touch with him
As a last resort, maybe just put it up for sale as-is, no returns. Fully disclose the issue and that the company is out of business of course. Then let the market decide. You may end up doing well. These things are out there and people may want them for parts or believe they can fix them. You can put a decent reserve on it if you’re worried about having to sell it for nothing. If possible shoot a video of the dac’s sonic issue so there will be no misunderstandings later. Good luck.
Mike Powell's website is