First thing, welcome to VCFED (as this is your first post).
Well done for saving it from the skip though.
First thing - please put your location in your profile so we know which part of the world you are in.
You may find a member of VCFED local to you?
Second, resist the temptation to power it on first. It may not survive the power-on process :-(!
I don't know of a "TI Professional" specific user group. This may give you the 'best course of action' if you can find a User Group.
Failing that - I would suggest you have a go yourself and try and get the machine working. You never know - you might get the Vintage Computer bug! Even if it does go 'bang' when you power it up - it hasn't really cost you any money has it?
I would suggest a little bit of analysis before you power it up though.
Can you identify what the main computer is exactly. For example, the machine came with a small amount of RAM (64K I think) but was expandable via a RAM card. There were hard disk options etc. etc. etc. Knowing exactly what you have got means that you can put that information into the 'advert' if you did decide to sell it. Some people who own one of these machines may be looking for specific add-on cards for theirs. In this case, you would be better parting it out - although some one may like to buy the complete system?
Do you have any manuals and/or software for it. It is likely that any software disks will be unreadable now - but you never know...
There is a load of documentation (including the maintenance manual) over here
http://www.bitsavers.org/pdf/ti/professional/.
I haven't found any software images yet.
If you fancy getting it going - I will be quite happy to help out.
A working machine will command more money than an untested or non-working machine - but getting it going yourself does have risks.
If you can't find a specific user group, we have a marketplace on VCFED and (of course) there is always a few other well-known sites...
Let me know what you would like to do.
Dave