[Histonet] old electron microscopes

[Joe]

A freind askded me to post this question to the list and see if he could get
any guidance.  He has two electron microscopes that appear to this untrained
eye to be older than the hills, or quite possibly alien artifacts.  One is a
Siemens unit (power supply is bigger than a fridge).  The other, I believe
is also a siemens unit, but it appears newer (relatively), than the other.
It's a bit smaller and has an orange body to the tube part.  He wants to get
rid of them and wants to know if they have any value on today's market?  I
tried the histoauction, but the page did not seem be working.  Any help
would be appreciated.