PDP-8/E questions - test-drb@ccmp.vtda.org

24 Nov 2001

On Nov 24, 21:03, ajp166 wrote:
...
  From: Pete Turnbull &lt;pete(a)dunnington.u-net.com&gt;

...
  The front bezel
(frame round the panel) has been repainted white, and  the
 paint has flaked or chipped off in places, to
reveal a chipped coat of
beige paint.  I'd like to refinish and respray it.  What's the correct
colour? 
 DEC gray  #68  A color close to eggshell toward very light gray. 
Sounds like a very pale grey, not quite white?  A lot lighter than the
panel on, say, an 11/34, or an 11/03?  I'll see what I can find.  Thanks!

...
  I'm toying
with the idea of replacing the LEDs with bi-pin bulbs, as the
panel was originally a bulb panel.  The resistors for the warm-up  current
 have been clipped out.  What value should they be?

 leave the leds, likely that mod was done very long ago.  The lamps
 tended to die too often. 
Yes, I'm sure it was done a long time ago, possibly even when the machine
was new.  Judging from the date codes on ICs and dates on some boards, it
was made in early 1974.

...
  What's J5
(3-pin Mate-N-Lok) on the PSU for? 
 Power controller. 
Are you thinking of the ones on the back (on the outside)?  This one is
inside, near the front, and I think Tony's suggestion (for the power fail)
is right.

...
  >Lastly (for now :-)), which direction should the
fans blow? 
...
  Unknown on direction, I think "out".  Filter
was a layer of foam where
 there
 was one.  I have a an 8f so they are somewhat different but the fans blow
 in
 across the cards.  The PS in the reaw with its own fan.  The 8e has the
 power supply down the left side(facing the front from front) and thefrom
 right
 (input) to left (out through the PS).  The power supply will tolerate
 higher temps
 if memory serves than core.  Keeping the core cool and at a relatively
 constant temp was the key to stable ops. 
In that case, I exercise my right to change my mind, and I think they
probably are the right way round.  The air blown out of the PSU isn't very
warm, but it will presumably be warmer when I put lots of cards in and give
it more of a load.

At some point, I would like to try to get the original core working (it
wasn't when I got it).  Expect more questions, about debugging 8K core
stacks, since I don't have a printset!

-- 
Pete						Peter Turnbull
						Network Manager
						University of York