AD584-M.............3456A
2.50066V.............2.50061V
4.99794V.............4.99791V
7.50011V.............7.50010V
9.99691V.............9.99690V
Next up is the secondary AD584-M reference. That was checked at the factory with an Agilent 34401A at 25 C ambient. The 3456A was powered up for 9 hours and the AD584-M powered up for 3 hours. Results as follows:
AD584-M.............3456A
2.49937V.............2.49933V
5.00030V.............5.00026V
7.50042V.............7.50039V
10.00096V...........10.00094V
Based upon these results the 3456A has experienced basically zero drift on DCV since the last time it was checked.


I don't have a high accuracy ACV reference other than a 1.00VAC which I wouldn't trust beyond 2 decimal places. When applied to the 3456A it reads 1.018286V. Good enough for my needs.
Next up is resistance. Leeds and Northrup 4747. This resistance box is showing some wear and tear so I had to do a lot of cleaning and futzing with it. The 2 binding posts are corroded and initially had a contact resistance of about 0.0450 ohms. With cleaning I got it down to 0.0148 ohms. But future I'll be replacing those binding posts with high quality pieces. Also on the 100 and 1000 ohm ranges some additional contact resistance is present. The switch decks show considerable wear and corrosion that deoxit won't touch. I'm considering using some metal polish. Future project. The 3456A had been powered up for nearly 12 hours. So the results are as follows:
4747...............3456A
1.0.................1.0159
10.0...............10.0191
100.0.............100.0629
1000.0............1000.317
The 1 and 10 ohm are OK while the 100 and 1000 are a little suspect but I think it's somewhat safe to conclude that the 3456A is OK.

Tomorrow will check my 10MHz "standard".