11/73 (ba23) bringup after 12 years in deplorable storage conditions

Jacob Ritorto jacob.ritorto at gmail.com
Thu Nov 20 23:46:22 CST 2014

  Well, things inside were clean and pretty minimally configured, so, with
all apologies, I jumped the gun and applied power, but I'm afraid the old
girl just didn't survive the twelve years of temperature transients.

  The illuminated ba23 power rocker switch lights up, but that's absolutely
it.  No fans, no familiar power supply squeal, no drive spinup, nothing on
the seven-segment CPU state display on the rear.  Seems thoroughly dead.

  I guess I need to start tearing it down and debugging the power supply as
I recall that it was at least doing more than this before the years of bad

  So I need to find power supply diagrams and start tracing things out,
right?  Any ideas as to where to begin?

On Thu, Nov 20, 2014 at 4:34 PM, Jacob Ritorto <jacob.ritorto at gmail.com>

> Good deal.  I guess I'm just gonna go for it after a cursory inspection
> and dusting.  It has stayed utterly dry; just the temp and dust were
> concerns.  I'll report back in a while..  Thanks!
> On Thu, Nov 20, 2014 at 3:55 PM, Ian S. King <isking at uw.edu> wrote:
>> At the very least, take a good long look at the power supply and its caps.
>> Has the storage, as bad as it's been, been dry?  If not, you'll almost
>> certainly have corrosion all over the place, especially in the fastons
>> run power to the backplane.  (I haven't looked at my own 11/73 in a few
>> years, but it's in a dry, temperature-stable basement.)
>> Best of luck! - Ian
>> On Nov 20, 2014 12:32 PM, "Jacob Ritorto" <jacob.ritorto at gmail.com>
>> wrote:
>> > Hey all,
>> >   I've been getting the bug worse and worse to start working on a real
>> > pdp11.  The Raspberry Pi / simh emulation is fantastic, but my hunger
>> for
>> > authenticity is becoming rampant.  I haven't run the youngest in my
>> fleet
>> > of pdp11s, the 11/73, since circa 2002 and if I recall correctly, it was
>> > becoming flaky and popping out to ODT inexplicably from time to time
>> back
>> > then (I think this is the one with the notoriously combustible power
>> supply
>> > wires that probably haven't been ECO'd yet -- need to get to that too).
>> > It's been lying in a warehouse in western Pennsylvania with no heat and
>> a
>> > lot of dust.  So, worst case, we're talking temperature transients
>> around
>> > 110 F and -20 F with no protection.  It did stay quite dry.
>> >
>> >   Think it'd be bad to simply blow the dust off and fire it up?
>> >
>> > thx
>> > jake
>> >

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