A HP 3314A has been one of my bench Freq Gen - with a bit of a bug that it would only work on 100 and 120V - not our 240V line voltage. I guessed it was a transformer issue - ie too hard so never looked into it till recently. The Schematic from HP.
https://www.keysight.com/main/gated.jspx?lb=1&gatedId=805471&cc=AU&lc=eng&parentContId=3314A:epsg:pro&parentContType=pt&parentNid=-536900193.536896858&fileType=VIEWABLEis for the earlier versions that have 2 separate switches.
Mine is of the later series with "soft-touch" buttons and what I nick name the "tumbling dice" all in one IEC connector, fuse holder and voltage selection switch. There is not a lot of room in the back of a 3314A so tracing out the circuit was a PITA
The voltage selector Cam activates several (2-3) of the 5 switches contained within this unit
Photo 1 - the outside view of the unit
Photo 2 the switches - with the cam removed and my labelling of the switches A to E
Photo 3 the Cam removed
Photo 4 Rob-CAD _ the switch connections and switches that the Cam activates in which positions, approximate resistance when the Active to Neutral resistance is measured
Photo 5 the Schematic NB Switch labelled F is really switch D
The issues in my unit were
- The Black Cable wasn't connected to the assembly
- Several of the Switches weren't connecting when pressed down by the cam - a bit of judicious bending was required
Be careful not to push the cam in too hard - this flattens the switch levers - they will then either stay "ON" - pressed forward or not reach the contact when the Cam pushes - ie stay "OFF"
If I have made any mistakes - please let me know
Hope this is of some help to others
Rob
PS This unit has one of HP better Easter Eggs
Edit error in labelling switch D in schematic - labelled as F
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