[time-nuts] Temex LPFRS-01

Sat Mar 17 16:58:17 UTC 2012

Yes, trichloroethylene is banned but not tetrachloroethylene that was used
when the first was banned.
Fluke.l has other LPFRS but beware: they are much worst than the one in the
picture, usually they go on auction so try to stay low should you ever want
to bid on one.
Actually item 29068516928 is on auction at $1.75 due on the 27th.

On Sat, Mar 17, 2012 at 5:20 PM, Mark Spencer <mspencer12345 at yahoo.ca>wrote:

>
> This is interesting.  I have two temex units one which works and one which
> has similar issues to yours.  The performance of my working one is quite
> good.   (If you want any specifics let me know and I can provide more
> details in a few days, but I recall it is notably better than either of  my
> 5680's.  I found the performance was best with a fan blowing air over the
> heat sink.)
>
> I'm glad you were able to get a refund for yours.  I gave up debating with
> the seller of my defective unit and wrote it off to experience (also I
> figured since it did put out a signal and locked up from time to time that
> it  wasn't entirely dead.) I probably should have pushed harder with the
> seller.
>
> I'll leave my busted temex in the projects pile for now.
>
> With the benefit of hindsight the picture I saw on ebay of the non working
> unit was not very confidence inspiring and I wish I had bought a second
> unit from the original source.
>
> The first unit was very clean and came with an attached heat sink and
> worked fine from day one.
>
> I've been contemplating building a system to periodically adjust the
> frequency and I want a second working unit before I put any time and effort
> into sorting out a pic tic micro controller solution.
>
> Please excuse typos and top  posting sending from pda.
> ------------------------------
> On Sat, 17 Mar, 2012 10:58 AM EDT Azelio Boriani wrote:
>
> >Yes, correct. The problem is that I have no deionized water nor a suitable
> >oven. The use of the tetrachloroethylene has simplified the procedure for
> >me (after all I was refunded, should the Rb fail it is not a money loss).
> >Anyway I'll try to locate a supply for high quality deionized water, the
> >oven can be built... I have one item to process more carefully.
> >
> >On Sat, Mar 17, 2012 at 3:21 PM, Bob Camp <lists at rtty.us> wrote:
> >
> >> Hi
> >>
> >> If it is water immersion damage, wash it in soap and water. Then rinse
> it
> >> in hot deionized water (above 10 mega ohms if you can get it). After
> that
> >> bake it at 80C with good air flow for > 24 hours. It still may rust, but
> >> most of the guck from the water will be gone.
> >>
> >> I once spent a lot of quality time with many truck loads of flood
> damaged
> >> gear....
> >>
> >> Bob
> >>
> >>
> >>
> >> On Mar 17, 2012, at 10:10 AM, Azelio Boriani <azelio.boriani at screen.it>
> >> wrote:
> >>
> >> > LPFRS from fluke.l? OK, then open it up and clean it, the LPFRS from
> >> > fluke.l suffers from high humidity/water immersion and usually are
> very
> >> > rusty inside. I have received one that was very bad but after cleaning
> >> with
> >> > tetrachloroethylene (translated with google) it is working properly,
> >> maybe
> >> > it will fail soon but now works. I complained with fluke.l and he
> >> refunded
> >> > me without asking to ship back the LPFRS.
> >> > TIP: handle with extreme care an opened LPFRS, there is a flexible PCB
> >> that
> >> > holds the DB9 connector that can tear in the corners.
> >> >
> >> > On Sat, Mar 17, 2012 at 10:59 AM, MailLists <lists at medesign.ro>
> wrote:
> >> >
> >> > Hello all,
> >> >
> >> > a friend purchased from the bay a <subj.> in the LPRO configuration.
> >> After
> >> > some problems encountered during the first power ups, he asked for
> help
> >> -
> >> > I'm passing the questions further...
> >> > After about 9 minutes of warm-up from room temperature (22°C) the lock
> >> > signal goes low, but after a short time starts to switch low/high with
> >> > decreasing low periods, until it remains high with short low pulses,
> >> spaced
> >> > at about 2 seconds. After power-down, and sufficient cooling time, the
> >> > cycle repeats.
> >> > First step was to reapply the thermal interface to the integrated Al
> >> > radiator, which helped a bit, the time during which the unit is locked
> >> > growing slightly.
> >> > Next step was forced cooling, which helped more, so the lock loss
> could
> >> be
> >> > attributed with high probability to elevated operating temperatures.
> The
> >> > temperature of the base plate (integrated Al radiator) at which lock
> >> gets
> >> > lost is about 40°C, so for a reasonable operation it should not pass
> >> about
> >> > 36°C, at which the power consumption raises to about 17W. That also
> >> means
> >> > that for a 1°C/W heat sinking - obtainable with a larger passive HS or
> >> > active cooling - operation above 30°C ambient gets practically
> >> impossible
> >> > (except refrigeration, Peltier, etc.).
> >> >
> >> > Any further help or suggestions are welcome.
> >> >
> >> > Regards,
> >> > bbg
> >> >
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