> Hi
>
> A failed ( = cold) oven on either a normal OCXO should give you a
"tens of ppm” sort of frequency error. At 10 MHz that would be over 100
Hz. Fractions of a ppm are less likely to be oven issues.
> Bob
Bob,
You're completely right about the ballpark of a total failure..
Anyhow, I
Hi
A failed ( = cold) oven on either a normal OCXO should give you a “tens of ppm”
sort of frequency
error. At 10 MHz that would be over 100 Hz. Fractions of a ppm are less likely
to be oven issues.
Bob
> On Nov 5, 2018, at 1:01 PM, Dr. Frank wrote:
>
> Walter,
>
> did you check on both
Walter,
did you check on both failing oscillators, that the ovens work properly
afterwards, or that the cases still get warm?
I once had a failing 10811, where the NTC was defect, maybe also after a
longer unused time.
As the heater draw an excessive current on turning on, (about 500mA for
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-Original Message-
From: time-nuts On Behalf Of Glenn Little
WB4UIV
Sent: Saturday, November 3, 2018 7:10 PM
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts] hp 10544A and 10811A ovenized oscillators
I had to "fix" a HP Cesium standard
I had to "fix" a HP Cesium standard oscillator while on an SSBN.
The problem was a failed op amp in the control circuit for the crystal
oscillator.
Due to lack of parts, the "fix" was to run the standard open loop with
nothing controlling the crystal oscillator.
Using an oscilloscope to compare
HI I have had experience with two 10811 oscillators which turned out to have
the same problem.
Inside there is a gold plated ferule mounted in teflon at the junction of the
tuning diode and
the transistor, obviously considered a very high impedance point, or may be
just sensitive to leakage.
Hi. I don't have a good answer to why both of your oscillators would have
drifted at once after the power cutout. However, I would be very interested in
taking a look at the bad 10811A. I have always been fascinated by these and
have wanted to take one apart (and try and understand/fix it) for
Hi
The change is suspiciously close to the electrical tuning range of a typical HP
OCXO.
The answer may be a failure of the bias on the EFC line …..
Bob
> On Nov 2, 2018, at 2:51 PM, Walter Shawlee 2 wrote:
>
> I have several of these as the -010 high stability timebase options
> in my
