Counter pron. HP 5384A check out.
Went really well - nothing wrong with it at all I can find.
Good first sign - original HP stickers still covering the screw holes. And oh yes it did have four actual HP feet which I have already removed here.
Insides - nice neat and tidy. Date codes point to late 1992 as the build date
Quick look towards the display
Hole ready for something better than the built in oscillator. I have taken measurements. Distance between the three pins is 0.3". Distance between the three and the single one is 1.5". Bounding box is 2"x 1.25" centred. Will knock a board up in Kicad for this and a footprint for the OCXO I have ordered.
10MHz "standard" oscillator. 3.6 Roentgen Not Great Not Terrible. Will be removed when the above is done...
Bottom of the board. Nice HP design, clearly Zukon output though as always
Close up
I'm really liking this. It's fairly small and it'll do 11 digits over 10s which is plenty. 11 digits only between 1.0 and 1.299 multipliers apparently. Assume that's a register or buffer limit but fine for standard 1/10MHz references