After seeing EEVblog's video #1017 on the Keithley 617 electrometer I thought, wow, I need to get one of those! OK so the one I bought won't measure higher than a few Giga-Ohms. The problem is caused by this leaky relay which was hard to troubleshoot. Keithley relay part number is RL-70 but this also is COTO 1240-0197 which is long obsolete and no longer available. I found COTO 7301-05-1000 in stock at Digikey and I think it will work.
