[time-nuts] LPRO-101 Heatsinking

Didier didier at cox.net
Mon Jan 12 20:03:05 EST 2009

I run mine with a 20V laptop power brick and it runs quite cool, just warm
to the touch with a heatsink, resting flat on a table with no forced air
flow. Even after a couple of hours, the LPRO was just warm. I have not
checked spurs (I expect the switcher to produce some, even though it is FCC
approved), but it would be easy to make a power supply filter, and as soon
as I get around to it, that will be next on my ToDo list.

The thermistor/fan controller is a good idea, it can't hurt the long term
stability to regulate the temperature. I sense another project coming up, as
soon as I have finished integrating the Thunderbolt with a distribution
amplifier and my GPS Monitor:



> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Neville Michie
> Sent: Monday, January 12, 2009 2:21 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] LPRO-101 Heatsinking
> Hi,
> The LPRO is shown to run down to 18 volt supply which reduces 
> the power dissipation, see the graph in the manual.
> Like Mike I put one on to a heatsink and used a tiny 
> under-run 12V fan to cool it.
> I placed a thermistor on the heat sink and controlled the fan 
> to keep the heat sink to about 37C.
> I insulated the assembly so it can handle low temperatures.
> It hold this within +or- 0.05 degree, which is a tremendous 
> assist to the non-ovened XO.
> It also reduces the power demand to about 7 or 8 watts.
> There is a small burden on the MTBF specs, but in my book 
> quite acceptable.
> When I finish building some more gear I will get the improved 
> performance data, cheers, Neville Michie

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