[time-nuts] Temex LPFRS-01

[Bob Camp]

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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