how nice is the playfield ? wear? broken plastics?
how nice is the cabinet, backbox, legs ? how is the general appearance ? if its nice and you decide to sell it one day and you fix it up, you might get more than you paid.
does it work 100% ? you said something about the lights can you tell us more?
that matters cause if it needs a new power driver board, new ones are 300 if its a WPC.
not sure if they make new system 11's. you might find a used one but it depends on whats wrong. that matters as to its worth.
i forget how many Dr. Dudes they made. most were System 11 and about 100 are the newer WPC version
which means that pinball machine could have 2 different kinds of electronics running the show.
i like the newer electronics some might like the System 11
good luck and you can read more here:
http://www.pinrepair.com/wpc/index1.htm#fuses