2 Apr
2002
2 Apr
'02
10:43 a.m.
"Douglas H. Quebbeman" wrote:
heh, believe it or not, there are two different, unreleated
things called "top hats" in some Primes... In my 2455, at
the top, underneath the removable top skin, is a small +/- 12VDC
power supply, called the "top hat PSU".
But the 750 wouldn't have had those... in the link below,
they are the three small rectangular vertically arranged;
my 2455's boards run vertical in the cage:
http://members.iglou.com/dougq/p2455/ICS&Cipher.html
OTOH, in the 750, the boards went in horizontally, so
you'd have seen the top hats left-to-right (at least
that's how they were in the P400 and the P650).
Glad I could help!
Regards,
-doug q
Now that my Prime 2455 is fully operational
again,
...
Ok, go for broke, swap in the remaining CPU board
set, replace
newly-provided CPU board interconnects (top hats) with my old
ones...
Thank you! Thank you! You've solved a twenty-year-old puzzle
for me and all the other Prime hackers at Westfield College.
You see, one day we were bored enough to read the Prime 750's
log book (must've been a day when the power failed or something)
and the Prime engineer had written the inscrutable:
Rotated top hats
Now, we didn't know what these gadgets were, but rotating them
seemed to be crucial to making our beloved Prime work, so we
just accepted it. Every time an engineer called, we'd look at
each other and say "He's here to rotate the top hats again".
Now, at last, we know what they are! Any chance of a photo?