It's time to restore the 11/45.

Paul Anderson useddec at
Thu Feb 5 01:45:14 CST 2015

You mentioned a G401, which I think is bipolar memory. There could be 4 of
these and 2 control boards. These are not needed and you might want to pull
them to make trouble  shooting easier.

Also I would be careful with them. They used to be expensive if you needed
to replace them.

The 45 and 70 share some boards, and there are 2 different backplanes/
board sets for each.

It sounds like you have the power supplies covered.

On Wed, Feb 4, 2015 at 12:43 PM, Jacob Ritorto <jacob.ritorto at>

> Hi,
>   Having gotten the 11/34 rig up to a good spec, I'm sufficiently excited
> to tackle the 11/45.  It's been powered off since 2004, when I briefly
> turned it on only to find a wild jumble of lights and that none of the
> front panel switches or knobs did anything to the lights.  Couldn't get it
> to run or deposit values or *anything*.  I therefore assumed it was badly
> broken and so left it until now.  It has stayed perfectly high and dry but
> has gone to extremes in temperature as the storage isn't climate controlled
> (this is in western Pennsylvania).  And there's a lot of dust.
>   I'm not going for museum perfection, but want it to be very presentable
> (lobbying to keep it as my 'art' in the living room long term if it's
> presentable enough :) and functional.
> So I'm looking for tips on how to go about it?  I was thinking:
> 1) Truck machine to living room, note positions of all wires / boards.
> Photograph, remove and clean dust from them.  Place on antistatic bench.
> 2) Thoroughly blow out dust and debris, vacuum backplane and wipe down
> chassis and wires with damp cloth.
> 3) Map out desired hardware config: I have available two Fujitsu 160 disks,
> three Fujitsu M2333K disks and two Fujitsu M2372K disks.  I need to decide
> how to rack and cable at least two, possibly up to four of them as the 8"
> ones have no mounting hardware.  Operational status on all is "hopeful."  I
> have two Emulex SC21s and an SC41 as well as an unmarked Xylogics Unibus
> SMD board.  I'm also tempted to mount an RX02 drive as I have a controller
> and quite a mountain of floppies supposedly containing weird old stuff.  I
> need to source an ethernet board and whatever cabling / bulkhead stuff
> follows.  DZ11, its dist panel and a Diablo 630 printer would be nice, too.
> 4) This would also be a good time to broach the subject of whether or not
> the capacitors need special love, or if that just adds more risk of
> destroying something.  Those familiar, please chime in as the archive is
> currently missing so I can't refer to the recent threads on this subject.
> Datapoint: I didn't mess at all with power supply / caps on my 11/34, which
> was stored right beside the '45 for the same timespan and it's running
> great now.  Datapoint 2: with my amateur electronics skills / status,
> there's admittedly some risk just having me poking around in there,
> "learning" things :-\   Plus, I'm afraid of death from esoteric high
> voltages that I hear are present in these old power supplies.  Is the 11/45
> one of them?  In a nutshell, this analog / power stuff is FAR FROM my
> forte; some hand-holding here would be most appreciated.
> 5) Insert an expendable Unibus module and power up; check & tune power.  I
> need direction on how to go about this.  Also, the bottom H742A power
> chassis isn't completely populated.  Not sure if that's acceptable, on
> purpose or bad.
> 6)  Reassemble, tidying up issues like missing / loose screws, rubbing
> cables, etc. along the way.
> 7) rt, 2.11BSD, rsx, rsts/e!   (mostly via vtserver -  I have a tu10 that I
> could get in on this deal, but its roller rubber has turned into goo and
> two cabinets in the living room is more than "pushing it."  Later date on
> that puppy. )
> Current module config starting from front of cabinet (yes, there are some
> gaps and M9200 jumpers I don't mention, too):
> M9301 + M787
> M8114
> M8115
> M8112
> M8113
> M8100
> M8101
> M8102
> M8103
> M8104
> M8105
> M8106
> M8108
> M8107
> M8109
> M8110
> g401
> M7800 + M9200 jumper
> H214
> G231
> G110
> H214
> G231
> G110
> H214
> G231
> G110
> Unibus cable runs out to third party external memory chassis, "Monolithic
> Systems Corp" Type MO v11/PDP11 P/N 300-0058-000, which is three quarters
> populated.  If this memory is broken, I'm planning to use an M7891 instead
> (is that OK?).
> No Unibus termination after that.  Is that weird / bad?
> Does this current config seem sound?  Is there a problem obvious just from
> this description that would account for the unresponsive front panel?
> Here's the power supply situation: There are two H742A power chassis.  Top
> contains h744, h744, h744, h744, h745.  Bottom contains H745, H746, open,
> H744, open.
> big thx!
> jake

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