radio problem solved; antenna one remains

[Preston Brown <pbrown@econ.yale.edu>]

OK, to all of you following the saga of the latest project (i.e. the rear 
speakers in my 86 5KCS didn't work) -- I have found the problem (with the 
help of my new bentley)!  The previous owner sure did some bad stuff with 
the wiring...one of the fuses in the power line to the booster/amp under 
the seat was completely missing.  So that problem is solved.  

However, the antenna still doesn't raise.  It is getting the "turn on" 
power signal from the radio plus another +12v on the red wire directly 
from the battery, so it should be operating according to some.  However, 
it isn't.  I have taken the antenna motor apart, (lots of grease!) but I 
really don't know where to start testing.  The motor itself has three 
leads(why?) going to it.  I can get continuity across two of them.  There 
is also a small PC board with some resistors, diodes, a transistor, and a 
capacitor, and two wire-wrapped things (relays?).  What's this stuff for 
anyone?  Circuitry to stop/start the motor when the antenna is fully 
raised/lowered?  Anyway, I need some help fixing this thing if anyone 
wants to help me -- I don't want to just "replace" it without knowing it 
is truly broken.  If I can determine it is broken and beyond my repair 
skills, I'll go scavenger hunting for a new one.

---
 -Preston Brown
  preston.brown@yale.edu