Josh Dersch derschjo at
Thu Oct 15 15:41:11 CDT 2020

On Sun, Oct 11, 2020 at 8:13 PM jim stephens via cctalk <
cctalk at> wrote:

> I agree.  Most devices are expected to be heated briefly to soldering
> temperatures, not heat soaked at that.
> Temperature in this case is much different than heat.  The designers of
> the devices must take into account what temperature is require to do the
> solder assembly function, and minimize the amount of heat the device is
> exposed to.
> On wave soldering machines the heat was quite low, and these would have
> been assembled then.  Even with current radiant oven techniques, the
> parts would fall off if there was an extended heat exposure.  They do
> that often enough now with heating problems with devices, with open
> circuit failures happening.
> If you're lucky and have a quick fire department response, the setup
> time on the equipment is at least 4 or 5 minutes.  Unless there's
> physical danger and the building involved may have people trapped, they
> take time to assess the fire, the propagation and there's more time
> before they attack.
> I've seen a couple of events and a couple of full exercises, it doesn't
> happen quickly.  Fire departments are sadly known for letting buildings
> burn into the basement if it saves life or property of other nearby
> structures.  You'd be lucky to get this out of a burned out building in
> most cases.  Once the fire is knocked down the heat will be present for
> quite some time afterwards, as they let it cool and clear flash fires,
> and take care of nearby property.
> thanks
> jim

Well, we'll see how bad these things really are.  The idiot I am, I struck
what I consider to be a reasonable deal for the 11/70 and 11/45 and I'll be
picking them up in November on a trip to SF I already had planned.  What
can I say, I'm a glutton for punishment.

A friend of mine went out and ot a number of decent high-res pictures of
the units.  The backplanes/wirewrap don't appear to be physically damaged,
and the boards inside look pretty decent, though I'm not holding my
breath.  (I was particularly surprised that none of the pot-metal card
stiffeners were warped or bent due to the heat, even near the front on the
11/45 where it's clear most of the heat was present.)  I do have a friend
with a spare set of 11/70 boards.  What sold me though was that the 11/70
has a PEP70 + Hypercache board set installed (which would be really cool,
assuming anything in there can be made to work again).

I figure worst case, I get a couple of DEC racks that'll work fine after
some sanding and repainting, and maybe I can send the chassis off to Ethan
if repair turns out to be impossible.

- Josh

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