[time-nuts] Temex LPFRS-01

[Azelio Boriani]

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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