Your experience with the specs of used old Keithley staff

[HighVoltage]

Some of these old Keithley instruments are still amazing today.
I am using these on a regular basis

617 Electrometer
181 Nanovoltmeter
230 Voltage source
220 Current source

Also, I am surprised how well they stay within calibration.

I also had some multimeters before but they drifted like crazy and I sold them again.

[Alex Nikitin]

I use 617 Programmable Electrometer, 263 Calibrator/Source and two 2015 THD multimeters all the time (all of these are on 24x7 for years), though I had to repair and upgrade the lot to start with. I also have 181 Nanovoltmeter and 705 Scanner, both in need of attention.

Cheers

Alex

[The Soulman]

I also had some multimeters before but they drifted like crazy and I sold them again.

My 192 multimeter drifted up and down some 40ppm per day, it required quite some modifications to get it down to 2ppm over the course of the day (dependent on ambient temperature).

[bastl_r]

In 2v range, the specs are 0,003% of reading +/-1,5dig in 24h at 23°C
That expects 30ppm...
If you want 2ppm you should have a 3458a or similar...

[The Soulman]

In 2v range, the specs are 0,003% of reading +/-1,5dig in 24h at 23°C
That expects 30ppm...
If you want 2ppm you should have a 3458a or similar...

Yes, or many fun hours of hobby time to build a high-stability 20V V-ref and directly feeding it into the mux (originally the ref for the 20 volt range was: 7V zener->divider/buffer to 2V->10x amplifier,
a lot of areas for potential drift and errors).
I do need want a more modern/fancy dmm like the dmm6500 but I'm afraid I will disappointed by its performance and that isn't something that is "easily" modified by the lack of schematics and the highly integrated construction. Also don't like fan noise.
Last year I've tried a €4K second-hand 3458a, that certainly wasn't my idea of fun.
Perhaps one day I'll try a Hioki 7275 (is a dc-voltmeter only), that uses a ltz1000 so that's a good start and even better it is mounted on a separate pcb that could easily be swapped by something diy if need be, sadly the "calibration" (actually adjustment) procedure isn't made public so that's a bit of a bummer.
Back on topic:

I really enjoy tinkering with these old brown Keithley's mainly because of the nice well written service manuals and schematics. 

[coppercone2]

old keithley staff is pretty grumpy, the company made alot of changes since the glory days

[HighVoltage]

The 705 Scanner is the cheapest of all and can really well be used for case replacement, if something is broken on a more expensive instrument.

The 617 Electrometer is an astounding instrument for the time and totally well suited for measurements today. I also have the successor, the model 6517B (Crazy new price 12,700 € + VAT) but I find myself to use the 617 more often, because it is so easy to use.