does anyone REALLY know how to repair these SS Zacs??  

they're GREAT when they work but are absolute BASTARDS when they dont

sorry for that little outburst    its just that a mate of mine has two that have been nothing but trouble for both him AND me,
i will definitely be keeping an eye on this thread, could be the answer to my mate's problems (and mine coz IM the sucker who is stuck with working on them)