[time-nuts] Re: TEMEX LPFRS-01 LPRO repair

[paul swed]

Dave I agree on the sweeping. If the units not doing that there is some
other failure.
A way to check that would be let the system warm up as usual. Then unplug
wait 10 sec. Then repower.
You should see the sweep.
Two things will happen it sweeps and stops as it finds the signal and then
locks.
Or it locks to some low noise crud that doesn't allow the lock to trip.

Paul
WB8TSL

On Wed, Apr 24, 2024 at 10:53 AM VE7HR via time-nuts <
time-nuts at lists.febo.com> wrote:

> I have been having lots of enjoyment out of my TinyPFA. It’s so small,
> easy to carry and quiet compared to my HP 5370B.
>
> I am testing it out on my existing pile of frequency sources. One of them
> is a LPFRS-01. It no longer locks. It locked for a few minutes when I first
> powered it up.
>
> Looking in the archives there has been a long standing thread on repairing
> these devices with several people in the same spot I am in on a used to
> work LPFRS-01.
> It no longer locks.
>
> Output from Serial port on mine is
> 8A 1C C3 8A 7C 86 A7 DC
> The 4th column is the VCO control voltage that should be sweeping when
> unlocked. So that is what the other threads seem to indicate.
>
> There are some nice teardown pictures of a unit at
> https://egidy.de/temex_lpfrs_lpro/
> With similar data output.
>
> I don’t think I have found any service information yet. If I have missed
> it please point me in the right direction.
>
> I have not pulled my unit apart bit I am not seeing the trimmer cap that
> has been speculated to be the fix in the pictures.
>
> Can anyone shed any light on what to twiddle?
> If I get it fixed I promise to post my results. It’s somewhat puzzling
> that there is a common question but no answer. Does this mean not one has
> fixed it or just not one has told us they have.
>
> Dave
> VE7HR
> Sent from my iPad
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe send an email to time-nuts-leave at lists.febo.com