Richard (Rick) Karlquist
richard at karlquist.com
Tue Oct 2 12:03:20 EDT 2007
The labels may or may not be significant. If the frequency
is indeed -2.94 Hz at 2.5V EFC, you could probably get it back
to 10 MHz by increasing the EFC voltage. You can also decrease
the bridge capacitor to bring the frequency up if necessary.
The factory was supposed to choose the capacitor to get 10 MHz
in the center of the EFC range. If this is not correct, the
oscillator is usually perfectly OK , and they just
goofed on the capacitor. The capacitor installation process
had a lot of problems. Should be safe to power it up and see
what the status is.
Jeroen Bastemeijer wrote:
> ); SAEximRunCond expanded to false
> Errors-To: time-nuts-bounces+richard=karlquist.com at febo.com RETRY
> Dear All,
> After some shipping time, my E1938 arrived today! :-) :-) :-)
> Thank you Rick!
> First thing was examining the board, oscillator and the HP-test
> notes/labels. Most of the specs mentioned there are logical and numbers
> are very reasonable. ;-) However, one spec drew my attention: "Hz off
> freq. after warm up: -2,94". Does anyone know what it means? Is this the
> offset after warm-up without EFC applied?
> The unit hasn't been powered up. Whit the hardware at hand I first want
> to read some docs to be sure about what I'm doing. For comparison, what
> other numbers are around for the "Hz off freq. after warm up"-spec?
> Final result of the HP-test was: PASS. So, I assume this number is OK.
> What is your opinion? Looking forward to your reactions.
> 73 Jeroen PE1RGE
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