That is beautiful work, the welded connections are really impressive. Obviously they had to take into account massive forces, vibration and possibly impact damage, but still, to see components welded in place is something I've never seen before, not even in very high end HF power electronics.
> The AGC that we're restoring belongs to a private owner who picked it up at a scrapyard in the 1970s after NASA scrapped it.
That is one lucky find. Imagine that it had not been found and scrapped for its metal value. The mind boggles at the potential destruction of such a historical artifact.
> the cordwood components are mounted differently from the other cordwood modules.
For those from cities who have never seen cordwood:
Cordwood is a stack of wood of short length seen from the endgrain, typically used when referring to firewood but also sometimes used in construction.
> ... Obviously they had to take into account massive forces, vibration and possibly impact damage ...
That's why they also glued them in epoxy. If you don't want you electronics to move (and thus break connections), put them tight in epoxy. And I mean completely glued in. No air left. This is as valid for modern solder joints as well as welded.
The AGC we restored was used for ground testing, so most of the modules weren't encased in epoxy. This made things much more convenient for us. We did have to dig through encapsulation to fix one module, though.
Well wire-bond (within IC packages) is a form of welding, so it's not so uncommon.. Also the electrodes within a vacuum tube were all welded. Also wire welding is very common (it's the main technique) in automobile wiring harnesses.
Suppose you had an old radio made with all welded construction. I wonder if service would be easier or harder? There is no un-welding (so you'd have to cut the broken component out), but making the new weld is faster than soldering.
> Well wire-bond (within IC packages) is a form of welding, so it's not so uncommon.. Also the electrodes within a vacuum tube were all welded.
Sure, but that is inside the components. This is on the outside, after the components themselves have been manufactured.
> Also wire welding is very common (it's the main technique) in automobile wiring harnesses.
That may be so today but it certainly wasn't in the 1960's.
And even today your typical automotive boars is just soldered. Makes me wonder whether satellites and current space and possibly aircraft circuitry is still manufactured like this.
I'm not an expert on this, but there's a famous case from 1998 where the Galaxy IV telecommunications satellite developed "tin whiskers" on it's soldered connections which caused an electrical short resulting in a total loss.
So, at least in this case solder was used on a satellite.
Solder is used extensively in satellites nowadays. The catch, though, is that you must use leaded solder, because the lead dramatically decreases the occurrence of tin whiskers. RoHS has been rather annoying in the aerospace industry, because anything RoHS compliant can't safely fly.
what is the welding process here (for external leads). i've been concerned about tig welding on enclosures with components tied to the frame ground..in fact i'm pretty sure i've destroyed some stuff that way
Almost certainly resistance welding. It's very fast and passes current only through the two pieces to be welded together, so avoids all the issues of stray currents and the other safety precautions needed with arc welding processes like TIG that generate UV and showers of molten metal.
19:50 in this video shows one in use in making a vacuum tube:
In the early 00s I went to upgrade the RAM in my father’s pre-built PC and was confronted with two sticks that had been welded in. It was a bit too bizarre for me to be overly upset.
> The AGC that we're restoring belongs to a private owner who picked it up at a scrapyard in the 1970s after NASA scrapped it.
That is one lucky find. Imagine that it had not been found and scrapped for its metal value. The mind boggles at the potential destruction of such a historical artifact.
> the cordwood components are mounted differently from the other cordwood modules.
For those from cities who have never seen cordwood:
Cordwood is a stack of wood of short length seen from the endgrain, typically used when referring to firewood but also sometimes used in construction.