Sadly, I have some conflicting info about the 42-23. I asked on the "timenuts" reflector about: Ovenaire OSC 42-23 2.5"x1.5"x3.25" box with pinouts on bottom (674-0010-000) 6 pins in a row Brian Davies replied: Yes the one I spoke about is OSC 42-23 the HP number is 08430-60064 which has now been changed to 0960-0718 and the cost is 1700 UK pounds. It was used in HP generators type 8340. Hope this is a help Pin 1 +20 volts for oven. Pin 2 Oven ground Pin 3 HOVC Pin 4 Case ground Pin 5 +22 volts oscillator Pin 6 Shorted to pin 5 Out put on SMA connector this is how HP used it in there 8340 series signal generators. How this is a help All the best Brian I share this info, but in my case, there is no SMA output. Also, pin 4 doesn't seem to be ground. I'll admit that 5 and 6 seem shorted together. Later: Someone asked on "time-nuts" for info about a Ovenaire model # is OSC 49-68 (out of a gigatronics siggen). The reply they got was about the OSC 42-23 "I don't have this particular OAM Unit - I have a model 42-23 - but I do have the pin-out for it, and it sounds very similar to what you describe, so maybe this will be helpful. Viewed from above - ie as you would look down on it when on a board, with the pins to the left of the unit, they read from top to bottom as: 1 EFC IN - feedback from 10k trimpot for manual adjustment of Freq out 2 EFC REF - source voltage for 10k pot, hot end - cold end left open. 3 VCC +12v -heater supply? 4 GND 5 RF Out 6 VCC +10v - Osc supply?