'84 5k A/C controller curiosity; also Pentosin

["G. Benedikt Rochow" <rochow@segosf.hlo.dec.com>]

Has anyone here ever taken the climate control controller apart to
see what sorts of electronics are inside?
I'm just wondering whether it's just a few standard
logic chips (as it should be - it doesn't do that much),
or some impossible-to-replace custom logic or microcontroller
chips?
(I'd rather ask now, before it fails stuck at full-cold
in the middle of the winter...)

Also, what sorts of motors control the temperature and
outlet flaps? While I may change my mind once I get the 
a/c fixed (next sprong, I guess), I rather favor separate
how-much-blow/how-warm/from-what-outlet controls over
automatic combinations...

PO woes, next installment: I thought the float in the Pentosin
reservoir cap was awfully short, making it look more like
an overflow switch than a low-level warning considering
where the min/max markings are. Confused me for a week; it
doesn't help that I can't get the outer lid off to clean
out the gunk that makes it impossible to see the oil level
from the outside.
Yesterday, topping it up before driving it to the shop for expert
diagnoses, I read the molded writing for the first time: "Nur
Original-Bremsfluessigkeit..." AAAAAA! The PO put on a brake
fluid reservoir cap, because, duh, it looks the same; it's
beeping at me, better pour some PS fluid in."

I have the distinct feeling that the original cap got stuck in
the low position, was replaced with this wrong cap, which started 
the adding-PS-fluid thing (as filling the reservoir high enough to
pacify the brake fluid cap float results in stuff coming out the 
top, as I found out; so he kept it overfilled with PS fluid)....

Incidentally, the owners manual says that driving with a failed
PS system is safe, causing only "increased steering and braking
effort". Has anybody tried this? My leaks don't seem to be too
horrible, though; when replacing the fluid, I could tell a
good difference in effort between turning the wheels with the engine
off and turning them with the engine just started, pumping
through the first sips of proper Goo2000.


-gbr