Keithley 213 quad voltage source nvram

[cncjerry]

I picked up a keithley 213 quad voltage source out of curiosity.  It's capable of pretty accurate voltage sourcing up to +/- 10v and can be used as an 8192 point voltage step generator as well.

At power on it indicates a 'ram' failure.  It uses a socketed common ram chip with battery backup.  It also had a rom for programs.  I assume the ram lost battery power.  The startup checks the ram, rom, and then the ram checksum.  If it lost battery backup, I would assume the last test (checksum) would fail.  I don't know how they test the ram.  The question is if they can detect the ram has failed other than a checksum, I assume they read a known location for valid data?   if that is the case replacing the ram and battery won't do any good, correct?

I opened a case on eBay as the seller's picture had only the power light lit indicating a good power on test whereas it fails when I power it on with blinking lights.  So I expect to return it unless a new ram (without an image) will fix it.

Any experienced 213 users out there?