I also want to see inside the 197, to compare it to the 197A. So please teardown for all to see
I've got a 197A which has an EL backlight already, but it was extremely dim when I bought it off eBay.
So I did a repair to replace that, but I wasn't happy with the result:
1) the new EL panel was narrower than the original, and it doesn't cover the entire LCD panel top to bottom
2) it has a light blockage in the upper left corner where the electrode is. This blocks the word "AUTO".
3) I asked for a white EL panel, but got a weird turquoise blue color instead .. ugly.. (it looks brighter and better on camera then in real life. In real life it's very, very dim. Almost not worth having there. I have not experimented with different voltages or frequencies to try to make it brighter, but since I don't like the color anyways, I never bothered )
Now, I think I will try to get a larger orange EL, to get a look similar to the Agilent U1270 series DMM or the U8000 series PSU's (second picture below). I don't know if the Agilent PSU's use LED backlights or EL panels.
[click for a bigger image]
I also have another Keithley 197A that is in need of repair. It doesn't take a stable reading (measurements are all over the place and won't settle down). I'll post that repair when I get to it