[time-nuts] Fixing an HP 5370A with a missing ROM board

Mark Sims holrum at hotmail.com
Sat Jul 25 14:06:54 UTC 2009


Another weakness of the 5370 oven oscillator power supply is the use of a simple zener diode for the oscillator power regulator.  The 10811 spec shows a 2e-10 change in freq with a 1% change in oscillator voltage.

Another surprising 10811 spec is the 2e-9 change with 50,000 feet of altitude (call it a 90% change in air pressure,  probably more).  Barometric pressure here can easily change from say 29 to 31 inches of mercury (call it 5%).  If the oscillator sensitivity to air pressure is linear,  one could see another 1e-10 change in freq with the weather.  Plus the thing is also rather sensitive to humidity (1e-9 over 95% relative humidity).  Also a 6e-11 change per degree C.



_________________________________________________________________
Windows Live™ Hotmail®: Search, add, and share the web’s latest sports videos. Check it out.
http://www.windowslive.com/Online/Hotmail/Campaign/QuickAdd?ocid=TXT_TAGLM_WL_QA_HM_sports_videos_072009&cat=sports


More information about the time-nuts mailing list