I was kind of amazed at the poor soldering across the board on this module, I wonder what the failure rate was on these things in actual use. I suppose the high heat load kept the joints flexible at least.
When I look closely that work actually looks fine. Solder flow is reasonable and I don't see cold joints. The only true WTF was where a resistor had been ripped out for whatever reason. Also it's unclear whether they had flux-core solder yet and they are essentially soldering in 3D. (Former electronics assembler here.)
I did a bit of cursory research and it would appear that flux core solder was invented in around the mid-20th century, so there's a very good chance that they weren't using flux cored solder.
According to Kester, the solder company, they were formed in 1899 to make flux cored solder. Looking at the 1933 Allied Radio clearly shows Kester rosin core solder.
Rosin core predates that computer by a half century, at least. Kester was formed in 1899 just for that purpose, according to them. Was just looking at Allied Radio 1933 and rosin core solder is prominent. Not sure why the comments; radio building was at high form in the early 20th century.
Thanks for that pointer, all I could find was a vague wikipedia article. Obviously soldering was well established. The specifics of what was available weren't clear.
I'm sorry, but are we looking at the same pictures? The soldering looks more than OK. For example, the solder used is just enough that it takes a pleasant concave shape on the terminals.
A lot of old point-to-point wiring and soldering does typically look kind of terrible compared to modern day electronics, probably because it was assembled by hand by workers just trying to crank stuff out out as fast as possible.
Reminds me that my Dad told me he worked at Ferranti in the early 50's building "logic modules". I noticed one on display at the CHM in Mt View [1] and sent him a picture. He said he thought it looked the same as the units he built back then. His soldering was always pretty top-notch though. Ferranti was a military contractor so had some experience with reliability.
Been soldering/desoldering that very type of equipment for many decades; it is perfectly normal, and what you would have seen in commercial products of the time, from TVs to computers to even military, IIRC.
Soldering looks just fine to me. Some flux residue, but not a problem here. The oxidization didn't come from the factory, and wouldn't be a reliability concern.
