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

[Razvan Popescu]

Hello,

I also had the same issue with mine and I replaced the 4 electrolytic
caps. As you see also in the teardown pictures they are rated 105
degrees C. I bought 125 degrees C version. After replacing the 4 caps it
locks in around 2 minutes and stays locked. Get high quality caps
because the physics package is quite hot and it will shorten the life of
the caps very fast if you replace it with cheap ones.

I hope that's the only problem and you can fix your LPFRS module.

73!
Razvan

On 24/04/2024 16:32, VE7HR via time-nuts 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