Hi Jim,
This behaviour reinforces my thought that there's something physically
wrong inside the unit. I'd be tapping it with the plastic handle of my
screwdriver while I rotated it to see if it would lose lock.
Think of it this way: Do you want to fix it now or have it fail again
in a few months when you're using it for something important?
Ed
On 2/9/2014 6:39 PM, Jamieson (Jim) Rowe wrote:
Hi again Magnus, Mark, Tom Harris, Ed Palmer et al,
Well, before performing any surgery on my tricky little beasty, I
decided to check its frequency swing limits when starting up in the
'inverted' position, and then when starting up in the right-side-up
position. Here's what I found, as before looking at the frequency with
my counter (GPSDXO 1pps timebase):
Inverted position: swings between 9,999,798Hz and 10,000,001Hz,
before locking.
Normal position: swings between 9,999,756Hz and 10,000,057Hz, a few
times.
But wait for it -- it then locked up, reliably, in the right-side-up
position!
So now I'm really confused. It looks as if whatever was wrong with it
before has somehow fixed itself, after running it for a couple of days
locked in the inverted position...
Anyway, I think I'll leave opening it up for a while (at least) --
since it's now running locked fine in the right-side-up position. I
don't want to tempt fate, while its OK. What's that old adage? If it
ain't broke, don't try to fix it.
Cheers all,
Jim Rowe
-----Original Message----- From: Jamieson (Jim) Rowe
Sent: Monday, February 10, 2014 8:05 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] How I got my FE-5680A to lock in Sydney,
Australia
Hi Magnus,
Thanks for your further comments. As you probably saw in my reply to Mark
Sims, I am proposing
to check the swing limits 'before and after' inverting the unit, to check
out the theory before I open it up and try tweaking C217.
Cheers,
Jim
-----Original Message----- From: Magnus Danielson
Sent: Sunday, February 09, 2014 7:34 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] How I got my FE-5680A to lock in Sydney,
Australia
On 09/02/14 02:57, Jamieson (Jim) Rowe wrote:
Hi Magnus,
Thanks again for those further suggestions. I do have a GPSDO, and I had
been able to use it with a counter to check that the FE-5680A was
swinging either side of 10MHz. But I didn't make sure that it was
swinging evenly each side of 10MHz . According to my notes it was
swinging between 9.999770 and 10.000036MHz -- i.e., about 230Hz low and
about 36Hz high. But it was spending more of the time below 10MHz than
above -- does this suggest to you that I should tweak C217 until it
swings by about the same amount either way?
Yes, that is exactly what I would do.
Cheers,
Magnus
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