Tom Uban tom at
Thu Oct 15 15:45:21 CDT 2020

On 10/15/20 3:41 PM, Josh Dersch via cctalk wrote:
> 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
Awesome news that someone is going to try to salvage the machines!

Best of luck!


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