maybe use a multi meter and see if there is any life in the sample chip, i take it you have opened it up? Did you get this from ebay? Just wondering if maybe you have inherited someones else's experiment gone wrong, i've damaged the sample chip on 2 vss200 but that was when i didn't know what i was doing, they basically worked but there was no sample option and it could be the case with the one you've bought if it looks like someone has had a go at this i would try and get your money back, esp if you have paid alot for it. Without the sampling option they are not really worthwhile.
Maybe you could get a new sample chip if you could find out what chip it is or if there is an equivalent, maybe gordon jcp (member of this forum) could help with that. Alternatively try and get a hold of the service manual, maybe that would be listed in it as a problem, i'm sure i have the service manual for the vss200 but i dont know how much use that would be, but they both have pretty much the same sampling ability. It does sound like the sample chip is goosed though.