Signaal Electronics Unit 1125 Err Detec Military 1984

[@SeanBZA]

Those resistors are also available to a custom value. You can tell them apart from the regular ones because the standard range is printed on the case, the special order ones are hand labelled with the same white ink, by the person who laser cut the glass substrate to the exact value. 0.01% tolerance, though you can also get them selected to be 0.001% tolerance in some ranges, over the full military temperature range from -55C to +150C, which is pretty hard to get right. Tiny little quartz glass substrate inside, with a evaporated resistor layer, composition and thickness depending on the range, and then etched to form a long zig zag pattern that is mostly non inductive, with areas on the ends of the long traces left wider to allow you to trim them, either with a laser, or by sandblasting (with a media so fine it looks like fine flour dust) to get the value to rise to the correct one. Pretty much guaranteed at room temp to be exactly the value on the cover, plus or minus 2 counts on the meter measuring it. Meter error being the biggest thing. Put it on a precision bridge, and you will find them to be in general equal to the bridge, which often, on the more expensive ones, uses them internally.

[@tpa6120a2dwp]

The way the wiring was done looks a lot like the unit was definitely intended for an application with high vibration and/or g loading - they tied together absolutely every wire where it was possible, also feeding a wire through a hole before soldering it to the PCB is like a tiny little strain relief for the solder joint. The larger components on the PCB have a wire around them that keeps them in place, and then what about those clear plastic blocks on the PCB - if they touch the lid, then they might be there to prevent mechanical resonances of the board... Very interesting construction, one can learn a lot regarding design for high reliability.

[@BGTech1]

All avionics used cable lacing

[@dougsaunders8670]

Those logic chips are all 5400 series, the military-spec version of 7400-series TTL. (Same parts but with a 5 instead of a 7 at the beginning). Much better temperature stability, ceramic cases, etc.

[@CornelisJoh]

The official name of the manufacturer was Hollandse Signaalapparaten, often abbreviated to Holland Signaal or just Signaal. Between 1956 and 1990 the company was owned by Philips, and then sold to the French company Thomson-CSF. Later the Defense division of Thomson was renamed Thales. For company history search for "Thales Nederland" on Wikipedia.

[@JoodAbbas-n9m]

Its made in holland ??

[@CornelisJoh]

I suspect so.

[@BGTech1]

Great piece of equipment

[@TeslaTales59]

Fab assembly! mil-spec for sure.

[@angelasangel6275]

I can't stop

[@TeardownOZ2CPU]

please dont stop

[@TheMovieCreator]

Mil spec is very typically conformal-coated indeed. I've seen it sometimes in really expensive older lab-gear too, but it's not common.

[@douro20]

Those "connector savers" are far more precisely made than a standard gender changer and can cost $200-300 apiece nowadays. Of course there are cheaper ones but no one in a serious lab would want to use cheap ones unless they have to, especially on avionics.

[@cursedvillager6931]

Very cool find, Signaal (now Thales NL) is mostly known for their excellence radar systems. So maybe that unit was used for radar or something?

[@Dustycircuit]

Holy ppm's Batman!

[@paulpaulzadeh6172]

Make reverse engineering we shall see how much you can