[time-nuts] E1938A oscillator pinning
SAIDJACK at aol.com
SAIDJACK at aol.com
Mon Aug 27 20:13:28 EDT 2007
Hi Bruce,
I got it to work, it even locks to -5Hz within 5 minutes and the Amber LED
goes off.
The problem was that I had only applied GND to the shield of the connector.
I added a wire to the EFC pin to EFC return, and connected the three GND pins
of the connector, and magically it started working.
Seems one of those "GND" pins is actually a "heater on" type of pin.
Now I will do some experiments, it seems EFC should be 2.5V for the output
to be on frequency (not 0V).
Another interesting observation: my unit has 2.532V on the reference output.
I could probably try to locate the reference, and replace it with something
more modern and stable.
Lastly, the unit seems to have a slow 2-4 second sinusoidial drift in parts
to the -11 when measuring it's output on my 53132A after about 10 minutes
warmup. Wonder if that's the oven heater control loop...
bye,
Said
************************************** Get a sneak peek of the all-new AOL at
http://discover.aol.com/memed/aolcom30tour
More information about the time-nuts
mailing list