Waters WISP HPLC autosampler sanpling system auto

Used Waters WISP HPLC autosampler. Upon powers up. the system message appeared- 501 or 902. I don't have the manual to get an idea what is it mean. It responded to some commands but my ability to test it is very limited. I have tested the cooling/heating unit- the temperature regulator works good. it easily achieved +4oC (cooling option). The top cover is missing. If not satisfied. You can return this unit withing 5 days for a full refund minus shipping both ways. Lot NO1