The picture, if attached, did not come through.
Probably it was stripped off by the mailing list software.
I did located what I believe you were speaking of.
A small white donut placed in the circuit board which
was an attachment point for the trimmer and a smaller
fixed capacitor and the blue
I have had two 10811 with EFC problems that turned out to be lack of soldering
of one internal joint.
This is a large PTFE ferule with several leads including the varactor and
trimmer going into it. For many
years the leads all contacted but finally one lead developed an oxide film. A
Maybe that is my problem. I definitely have a problem.
I am able to get the EFC to work on some occasions.
Usually it will work if I run the trimmer all the way
out and toggle the power. I can then adjust the trimmer
and get things working. But if I give the box a rap
the frequency jumps and
I have found a pic of the dry joint,
this one was just a dry joint with resin insulating the connection,
the other never had any solder applied.
cheers, Neville Michie
On 17/11/2012, at 11:09 AM, Chris Howard wrote:
Maybe that is my problem. I definitely have a problem.
I am able to
You all were right, my targeting of the 50 ohm resistor
across the oscillator output does not seem to have solved the
problem. A good thing to do, probably, but not the answer.
While I was all excited about the resistor change I also
mapped out the control voltage (EFC) vs frequency change.
I
Hold the Up arrow down for 3 sec and put your counter into the 10 sec
range.
That will give you another digit of resolution. Now the LS Digit will be
1e-10 / count enough to test short term delta stability of many things.
ws
- Original Message -
From: Chris Howard ch...@elfpen.com
Hi
On a normal 10811, you should see at least +/- 1 Hz change. It should go
from 10,000,001.xx to 9,999,999.xx. That of course assumes the counter
reference is right on frequency. Since it may not be, it's the 2 Hz delta
between +5V and -5V you need to spot first.
Right now you data shows 0.1
Chris:
This says your EFC circuit is not working, and you are only
getting 0.05 Hz frequency change across the -5 to +5 EFC range.
The spec on the HP10811 is 1.0 Hz minimum.
And, yes, in a counter the EFC circuit is not used, so no one would
know if it failed.
It is very simple circuit. The
Chris wrote:
If I read this correctly, I'm looking at
9,999,999.97 Hz ?
Correct -- the small digit to the right is the exponent. As others
have mentioned, by holding the UP arrow key in for about 3 seconds,
the 1992 will switch to a 10-second gate and give you one more digit
of
On 11/15/2012 3:49 PM, Charles P. Steinmetz wrote:
.90 VDC 9,999,999.90
How and where are you measuring the EFC voltage? Are you sure the
voltage on the EFC pin of the 10811 (Pin 6) was the same as you measured?
Was the EFC return pin (Pin 5) connected to the oscillator supply return
Hi
I think I'd try grounding pins 4 and 5….
Bob
On Nov 15, 2012, at 11:15 PM, Chris Howard ch...@elfpen.com wrote:
On 11/15/2012 3:49 PM, Charles P. Steinmetz wrote:
.90 VDC 9,999,999.90
How and where are you measuring the EFC voltage? Are you sure the
voltage on the EFC pin
Chris wrote:
According to the documentation I have, pins 2, 4, and 5 are all tied
together internally
I think you may be correct. My recollection was that it needed to be
done at the connector, but I may be mis-remembering. Worth a check, though.
If you have Pin 6 ranging from + 5 V to -
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