3458A and SNAPHATS

[Grandchuck]

My user defined key programming was lost due to a dead cell in a SNAPHAT.  Luckily, the calibration data were OK as the other SNAPHAT had a little life left.  It was fortuitous that the non-critical cell died first.




I found MJLorton's video () to be helpful.  I ordered replacements from DigiKey (part# 497-3690-5-ND).  They arrived quickly and appear to have been manufactured in 2020. 
The video mentioned 48 mAh parts.  I am wondering if that was because his unit had been repaired?  It seems that the 120 mAh parts would/should always be supplied by Agilent/Keysight?
The replacement process is straightforward ... do be sure to have the DMM powered on to maintain the calibration.

Many thanks to TiN for the information on his website and the link to the video!