3 Mar
2003
3 Mar
'03
3:06 p.m.
Well, I finally got around to testing the PSU on my 11/34. I measured at the
backplane connectors with no backplanes plugged in. Everything checks out
except for the -5V and +20V. Accordingly, the LED at the bottom of the H745
brick (regulator 1) does not light. However, some of the other voltages
coming from the H745 (according to the BA11-K FMPS) seem to be OK.
Does anything in the machine even need -5V or +20V? If not, can I leave the
bad brick in place? I have: KD11-EA, KY11-LB, DL11-W, MS11-JP, M7850 parity,
DZ11-A, RK11-D. I'll be adding a RX11 at some point. Someone enlighten me,
please. :-)
I'm pretty sure I have a spare brick.
Also: what are these signals on the 6-pin backplane mate-n-locks?
- AC LO
- DC LO
Something I learned: If you have a H785 brick in your 11/34 BA11-KA cabinet,
ignore what the 11/34 and KY11-LB manuals say about battery backup and the
rotary power switch. You can indeed have a battery backup with a BA11-K, and
the switch on the KY11-LB works as you think it should. You must connect the
ribbon cable from the H785 to the corresponding connector on the KY11-LB, or
the H785 won't work. You must NOT connect the one-wire connector from the
H785 to P4(?) of the AC input box, or else your machine won't turn off,
regardless of the rotary switch. Clear as mud?
--
Jeffrey Sharp
3 Mar
3 Mar
3:25 p.m.
On Mon, 3 Mar 2003, Jeffrey Sharp wrote:
Does anything in the machine even need -5V or +20V? If
not, can I leave the
bad brick in place? I have: KD11-EA, KY11-LB, DL11-W, MS11-JP, M7850 parity,
DZ11-A, RK11-D. I'll be adding a RX11 at some point. Someone enlighten me,
please. :-)
Something makes me think that the -5V might be needed for the Unibus, but
I'm probably wrong.
I'm pretty sure I have a spare brick.
Also: what are these signals on the 6-pin backplane mate-n-locks?
- AC LO
- DC LO
Oooh, I know this one. They are set to a logical 'high' state when the AC
voltage coming in or any of the output DC voltages are low, respectively.
Pat
--
Purdue Universtiy ITAP/RCS
Information Technology at Purdue
Research Computing and Storage
http://www-rcd.cc.purdue.edu
4 Mar
4 Mar
9:56 a.m.
Well, I finally got around to testing the PSU on my
11/34. I measured at the
backplane connectors with no backplanes plugged in. Everything checks out
except for the -5V and +20V. Accordingly, the LED at the bottom of the H745
brick (regulator 1) does not light. However, some of the other voltages
coming from the H745 (according to the BA11-K FMPS) seem to be OK.
I thought the H745 provided +20V and -5V only. What other voltage do you
think it's providing...
Does anything in the machine even need -5V or +20V? If not, can I leave the
AFAIK it's only needed if you have core memory. Certainly I've run 11/34
machines without one, with MOS memory and a fair selection of interfaces.
Generally you only need the +5V, +15V, -15V lines.
bad brick in place? I have: KD11-EA, KY11-LB, DL11-W,
MS11-JP, M7850 parity,
I would unplug the 8 pin connector from any brick you're not actually
using, particularly if it seems to be defective. Since that's all the
connections to the brick, the defective brick can be left physically in
the chassis.
DZ11-A, RK11-D. I'll be adding a RX11 at some
point. Someone enlighten me,
please. :-)
I'm pretty sure I have a spare brick.
Also: what are these signals on the 6-pin backplane mate-n-locks?
- AC LO
- DC LO
Power fail lines (like the Power Good line on a PC/AT PSU). Basically,
any device/mounting box can pull those lines low if it detects a power
failure, and the CPU (or other devices can then shut down in an orderly
fashion.
-tony
11:59 a.m.
On Tuesday, March 4, 2003, Tony Duell wrote:
My multimeter shows the following voltages on the mate-n-lock connectors
J3,5,7,9,11 relative to pin 8 (ground):
+15V at pin 6
+5V at pin 12
-15V at pin 15
The printset -- specifically, sheet 2 of 5410864-0-1 "PWR DIST BOARD" (page
40 of the BA11-K FMPS PDF I downloaded) -- leads me to believe that these
voltages can come only from the H745.
Other documents agree with you, though. I'm confused.
Well, I
finally got around to testing the PSU on my 11/34. ... Everything
checks out except for the -5V and +20V. ... However, some of the other
voltages coming from the H745 (according to the BA11-K FMPS) seem to be
OK.
I thought the H745 provided +20V and -5V only. What other voltage do you
think it's providing... I would unplug the 8 pin connector from any brick
you're not actually
using, particularly if it seems to be defective. Since that's all the
connections to the brick, the defective brick can be left physically in
the chassis.
Thanks. My next step, then, is to pull the cards, inspect them, and clean
out the backplanes and other currently hard-to-reach spots. Then I'll check
for bent pins on the backplanes and eventually test a minimal card set.
I'll double-check, but it looks like all my NPG jumpers are in. I don't have
any NPR peripherals except for the RK11-D, and I have ample "bleeding
knuckle" G727A grant cards. I don't *expect* any grant issues.
--
Jeffrey Sharp
5 Mar
5 Mar
8:38 a.m.
My multimeter shows the following voltages on the
mate-n-lock connectors
J3,5,7,9,11 relative to pin 8 (ground):
+15V at pin 6
+5V at pin 12
-15V at pin 15
The printset -- specifically, sheet 2 of 5410864-0-1 "PWR DIST BOARD" (page
40 of the BA11-K FMPS PDF I downloaded) -- leads me to believe that these
voltages can come only from the H745.
Are you sure? I've not got the prints in front of me, but I thought all
the -15V lines came from the H754 module, and the +5Vs from
H744/H7440/H7441 modules. With the +15V coming from the PCB under the
mains transformer.
Oh, hang on.. I know what you're seeing, I think. Those are the Vb
(battery-backed) lines. The battery backup interface brick fits in place
of the H745 -- the idea being that you only need the H745 if you have core
memory, which is non-volatile, and you only need the battery backup unit
if you have (volatile) MOS memory. The battery interface uses a different
8 pin mate-n-lock connector in the harness, though.
If you don't have the battery backup unit, then the Vb lines are linked
to the normal rails via jumpers (on the backplane I believe).
-tony
4:54 p.m.
Thanks for your help, Tony and Patrick. I think I have this mostly
understood. Just a few things remain.
On Wednesday, March 5, 2003, Tony Duell wrote:
Oh, hang on.. I know what you're seeing, I think.
Those are the Vb
(battery-backed) lines. The battery backup interface brick fits in place
of the H745 -- the idea being that you only need the H745 if you have core
memory, which is non-volatile, and you only need the battery backup unit
if you have (volatile) MOS memory. The battery interface uses a different
8 pin mate-n-lock connector in the harness, though.
Ok, problem found: me. I got confused by the print set on the representation
of front vs back views, and thus I had my regulator positions backwards. We
were both also confusing the H745 and H754. Everything (except one thing)
looks fine now. Here's what I have:
Under Xformer +15V
Brick 1: H745 -15V
Brick 2: H7441 +5V
Brick 3: H7441 +5V
Brick 4: H785 +5VB, +15VB, -15VB
The H785 doesn't produce -5V or +20, so it is certainly OK that I'm not
finding those voltages on the backplane power connectors!
My current understanding (no pun intended) of the H785 is that when it is
not running off the battery, it produces +5VB, +15VB, and -15VB with current
from the mains transformer. Am I correct?
My testing shows that I have the correct voltages on all the right pins,
including -15V. However, the LED on the H745 (-15V) does not light. What
does this mean?
--
Jeffrey Sharp
6 Mar
6 Mar
5:51 a.m.
Ok, problem found: me. I got confused by the print set
on the representation
of front vs back views, and thus I had my regulator positions backwards. We
Wait until you sart populating a large backplane of flip-chips like an
RK11-C or worse a DX11. The printsets show the backplanes from the wiring
side you seen. Took me a bit of time to figure that one out (as in 'Hey,
why are all the PCBs in the wrong slots??').
were both also confusing the H745 and H754. Everything
(except one thing)
looks fine now. Here's what I have:
Under Xformer +15V
Brick 1: H745 -15V
Brick 2: H7441 +5V
Brick 3: H7441 +5V
Brick 4: H785 +5VB, +15VB, -15VB
The H785 doesn't produce -5V or +20, so it is certainly OK that I'm not
finding those voltages on the backplane power connectors!
Yep.
My current understanding (no pun intended) of the H785 is that when it is
not running off the battery, it produces +5VB, +15VB, and -15VB with current
from the mains transformer. Am I correct?
I believe so. I've never had an 11/34 with the battery backup option though.
My testing shows that I have the correct voltages on all the right pins,
including -15V. However, the LED on the H745 (-15V) does not light. What
does this mean?
The 'LED' runs straight off the output rail, so there's little that can
go wrong if the output is somewhere near -15V. Most likely you have one
of the older H745s with a light bulb not an LED, and the bulb has failed
(they do this from time to time ;-)). Or I suppose if you have an LED
that, or the series resistor, could be defective.
-tony
1:42 p.m.
New subject: PDP-11/34 PSU Yet Again (Thanks)
On Thursday, March 6, 2003, Tony Duell wrote:
Thankfully, I already figured that out! I can imagine that causing all sorts
of problems, including much let-outage of magic smoke.
I got confused
by the print set on the representation of front vs back
views
Wait until you sart populating a large backplane of flip-chips like an
RK11-C or worse a DX11. The printsets show the backplanes from the wiring
side you seen. Took me a bit of time to figure that one out (as in 'Hey,
why are all the PCBs in the wrong slots??'). Most likely you have one of the older H745s with a
light bulb not an LED,
and the bulb has failed (they do this from time to time ;-)).
That is probably exactly what is going on. Thank you and Peter for the
information. If all goes well with other things, I'll be testing the CPU,
memory, and console serial line this weekend.
--
Jeffrey Sharp
7962
days inactive
7965
days old
7 comments
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ard＠p850ug1.demon.co.uk -
jss＠subatomix.com -
pat＠purdueriots.com