It's an HP3437A:
https://www.amplifier.cd/Test_Equipment/Hewlett_Packard/HP_meter/3437A.html
No idea what's cool about it - it has the nice bubble display and button that might be useful as spare parts for other HP instruments.
Well spotted. Yes, it's the buttons. Specifically, that the buckling-spring switch bodies have NOT been heat-staked to the PCB. They are held in place only by the front metal plate. All three units I've bought are like that, so it was apparently manufacturing standard for the 3437A.
I don't know of any other HP instrument with those switches still having their mounting stakes intact. Which means the HP3437A is the only source of replacement switches that I know of.
Are there any other HP instruments using the same button-switch mounting scheme?
It would be good to find something that:
* Has a lot of buttons,
* Is fairly cheap and common on ebay,
* Is relatively light so shipping doesn't cost a fortune.
* Is really obsolete and useless, so stripping it isn't painful. The 3437A is quite a nice instrument.
Ideally I wish I'd find a box full of just those front panels, for cheap. Like that's going to happen.
10^-16A.
Wow. Is there any existing instrument that can measure that?
Now I want one too.
Recently arrived here (see pic.)
The Hantek DSO2D15 scope, not beautiful and tallented Korean pianist-youtuber Leezy, unfortunately.
There's a funny story about the shipping, but I'll tell it later.