Altair Turnkey and some DEC stuff cheap

[Chris Elmquist]

ah...  "Barn Fresh".  Plenty of experience with that here.

Personally, I think mice, like many of us, have a special affinity for
DEC equipment.

I brought home an RX02 once that was severely affected.  In the end,
with not much to loose, I pressure washed it in my driveway :-)  The PCB
suffers from the same re-etching of traces you describe and someday I
will fix it up.   I believe the drives have actually survived.  The power
supply did not.

The only other thing I found more "interesting" was a very large stash
of RL01, RL02 and RK05 packs we came across, in a pole barn, that were
completely infested with sugar ants.    These packs were up on a shelf
in the barn, not laying on the ground, so the ants had to seek them out.
They had built tunnels (by bringing in the sand) in, on and around these
packs and had very well established colonies in most of them.

All I can figure is there was some chemical in the pack itself or the
boxes or wrapping they were in that attracted them.

Incredible mess.

There is a special place in hell for people who leave this gear to rot
and become infested in places like this.

Chris


On Thursday (04/09/2015 at 08:49AM -0400), Noel Chiappa wrote:
>     > From: Bill Degnan
> 
>     > These are best for someone who has experience cleaning a "barn find"
>     > ...
>     > * items contains/contained a rodent nest.
> 
> Those who missed out on this deal may find this sequel comforting.
> 
> There was one aspect of this (which Bill alluded to somewhat eliptically -
> perhaps out of delicacy, or perhaps he assumed that anyone who'd done one of
> these would already realize the full implications :-), but which didn't
> really impress itself upon me until I started the ride home - at which point
> I started to get olfactory clues. Yep, some of you know what I'm talking
> about.
> 
> Animal urine.
> 
> Of the three boxes, one (the '11/44' - it was actually just a BA11-K) was
> totally sodden inside (those nests are basically giant sponges), and one of
> the 11/34's was half-sodden. The thing about animal urine that's really a
> problem is not the smell, or the mess - it's that it's _incredibly_ corrosive.
> 
> >From the condition of a couple of the cards which had gotten the worst, I
> think there was actually some galvanic activity between the copper traces,
> and something else - maybe the iron in the chassis? Traces were quite
> literally eaten right off the cards. You can see the trace heading towards
> one of the gold-plated contact fingers, and then - poof! - it disappears.
> Dozens of traces on those two cards have big gaps in them.
> 
> Although now that I think about it, it couldn't have been galvanic activity
> which dissolved the copper in the traces; if I remember my inorganic chem
> correctly, iron is above copper on the galvanic activity scale. But anyway,
> 
> Also, totally amazingly, quite a few of the gold-plated contact fingers also
> have damage! One is quite bad - although luckily I think there's a patch left
> where the contact would be, so that can probably be saved. Whatever was going
> on must have eaten the copper out from underneath, and then the gold just
> washed away.
> 
> So I think all those traces can be repaired, if there's ever a use for that
> interface (an RH11). Just a lot of wires to solder in....
> 
> 
> The other problem is the backplanes. DEC boxes put the backplanes at the
> bottom, so these nests were resting on the backplanes. Having cleaned them off
> (well, stage 1 cleaning), I _think_ that, amazingly enough, the contact pins
> are OK. (Now that I think about it, they are tin-plated - so there's the other
> end of the galvanic activity. Ah, well, better to eat the traces than the
> contact pins - those would be almost _impossible_ to repair.)
> 
> The real problem is that there's 'grup' (a Dave Clark neologism) in the thin
> space between the plastic contact pin housing blocks and the PCB. Needless to
> say, one can't take the PCB off to get in there...
> 
> So my plan of action is to stick them in water for a couple of days, and
> then use a water jet to try and get down in the thin gap between the contact
> blocks and the PCB, to clean it out.
> 
> Does this sound OK? I can't think of a reason why immersing a backplane in
> fresh water for a couple of days would do it any harm, but maybe I'm missing
> something?
> 
> I just think it's critical to recovering these to get as much out of that
> area as I possibly can. If an open develops somehow, well, that can easily be
> fixed with a wire. But a short.... you're screwed.
> 
> 
> Moral of the story: if you're going to store your antique computers in a barn
> - make sure to keep the rodents out!
> 
> 	Noel

-- 
Chris Elmquist