I went to use my CS-152 yesterday. Flick the power switch on with a loud chunk. Dial the knobs to all 9's and an X, Set the current multiplier to 100mA. And...
nothing. Check the fuse, it worked last month. Check the 10v output(mighty convenient), nothing.
Lets open up the reference.
Well, there's your problem. The ground lead became disconnected(broke off)
Spurned on by Pigrews tear down, lets go further.
Looking at the back of the reference we can see a few wires. The 2 heats hrunk white wires lead to a 1Meg thermistor. This thermistor bead is sitting in a tunnel that is filled with sillicone. The 2 red wires go to the heater. The Blue/purple wires connect to the black thermal cutoff. This is used to shut of power to the heater, in the event of thermal runaway.
From this angle we can see the voltage reference in a metal can. The whole board is wrapped in a layer of tape. Helps keep the wires from getting pulled out, and makes it easier to slide in. You can see how there was a cutout machined inside the case to allow fitment of the wires. Very nice. I will give NH some credit. They can do a really good job on machining.
Drum roll please.
Presenting the voltage reference.
…
..
My phone decided to delete 4 pics of the board when I uploaded them to my computer
Well here is the bottom of the board.
The voltage reference is a 0.005% accurate, 2ppm%/C Burr Brown REF101, made in the USA!!!
I will not tear down that voltage reference board again.
REF101JM specs
http://pdf.datasheetcatalog.com/datasheet/BurrBrown/mXqxxqw.pdf