At least not a power supply cap. No change on a different PS. Do you
mean the oscillator output coupling cap?
12V for the oven because inside the outer oven lives a 10811-60158 ( see
http://www.realhamradio.com/GPS-oven-journey.htm ) that, as by the specs
sheet, is specified 12 to 30 V DC, 11 W max. at turn on (mine draws some
9 W), and Steady state power drops to approximately 2 W at 25°C in still
air at 20 V (mine draws some 1.9 W at 12 V without powering the outer oven).
Adrian
Azelio Boriani schrieb:
And, why 12V for the oven? The 10811A manual states from 20V to 30V for the
oven. 12V for the oscillator itself.
On Sat, Oct 13, 2012 at 4:34 PM, Tom Knox <[email protected]> wrote:
Sounds like another dead cap.
Thomas Knox
Date: Sat, 13 Oct 2012 14:51:54 +0200
From: [email protected]
To: [email protected]
Subject: [time-nuts] HP 10811A failure
Hi All,
both of my double oven 10811A's have been running flawlessly until now
when I noticed that the output power has dropped by about 3 dB (measures
only 4...4.5 dBm at 50 Ohm load), and the noise floor has gone up by
about 20 dB, while the frequency is still spot on.
I used them for various mesurements, so I can unfortunately not remember
what might have caused the failure. Only the 12V linear lab power supply
that fed the heaters had developed a completely dead filter cap, so the
feeding voltage was a 100 Hz sawtooth rather than DC. The heaters appear
to be still working though. I'm only using the internal heater. They
draw some 700 mA at power up and drop to around 150 mA each when warm.
So the oscillators are unlikely to be cooked inside. Something must have
happened to the 10 MHz output, possibly an ESD issue?
Before I start taking them apart, can anyone tell what has happened or
what to look for first?
Regards,
Adrian
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