[time-nuts] Ebay FE-5680A Rb I see the price has gone up for these

Peter Gottlieb nerd at verizon.net
Tue Dec 20 12:33:47 EST 2011


A milled flat surface and/or thermal paste is not required for heat transfer, it 
just makes it better.  There must be some removal of heat; consider that to 
reach thermal equilibrium the heat flow out of the unit must match the power 
absorbed.  It seems that about 12 watts is going in, so eventually 12 watts must 
be flowing out if the temperature is to remain steady.

I would not want mine to run at 60C, I would rather it be at a more reasonable 
35-40C on the baseplate, just for the electronics.

I am going to mount mine to an existing aluminum panel in my target unit using 
the provided mounting holes and be done with it.

Peter


On 12/20/2011 12:18 PM, John Howell wrote:
> Agreed 340mA seems too high, mine takes 87mA. There has been much
> comment on [time_nuts] about the temperature of these units varying from
> 'let 'em get hot' to 'must heatsink'.
>
> In my experience items that require a heatsink have a milled flat surface
> to mount to a sink, not a thin case that would only touch in places.
> Furthermore I didn't think fiberglass circuit board was famous for its heat
> conducting properties. No sign of any heat transfer compound either. So
> do I conclude they need a bit of cooling?
>
> I agree with you Pete and would really like to know what the  makers say
> about all this!
>
> Best wishes,
>
> John.
>
>
>
> On 20 Dec 2011, at 16:22, Peter Bell wrote:
>
>> 340mA seems really high - all the ones I've seen take about 90mA - and
>> I would strongly recommend putting in on a heatsink, or at least
>> bolting it directly to the chassis.  In my experience, they don't
>> actually malfunction when operated without one, but the housing gets
>> very hot (and, presumably, the insides get hotter still) - after 24h
>> running sitting on a foam mouse mat open to the air, the case hit
>> about 59c - I can't help thinking that isn't going to be good for the
>> long-term health of the unit.
>>
>> Regards,
>>
>> Pete
>>
>>
>> On Wed, Dec 21, 2011 at 12:03 AM, Chuck Forsberg WA7KGX N2469R
>> <caf at omen.com>  wrote:
>>> Mine requires the 5 volt supply at 340 ma.
>>>
>>> Are there nay manufacturer's instructions about mounting, ventilating,
>>> or heat sinking these units?
>>>
>>> My current thinking is to mount it on standoffs on the back of the chassis
>>> that houses my Thunderbolt.
>>>
>>> Perhaps I should place it where it can warm up Princess.
>>> (Notice the magnet on top of the oscillator.)
>>>
>>>
>>> On 12/20/2011 07:13 AM, Roy Phillips wrote:
>>>>
>>>>
>>>> --------------------------------------------------
>>>> From: "Rex"<rexa at sonic.net>
>>>> Sent: Tuesday, December 20, 2011 1:10 PM
>>>> To: "Discussion of precise time and frequency measurement"
>>>> <time-nuts at febo.com>
>>>> Subject: Re: [time-nuts] Ebay FE-5680A Rb I see the price has gone up for
>>>> these
>>>>
>>>>> FWIW. I just hapened on this power supply in an ad. You might find a
>>>>> fixed voltage one somewhere cheaper, but the price seemed ok, so here it is
>>>>> for consideration...
>>>>> http://www.mpja.com/email/12-13-11.asp?r=284759&s=2
>>>>>
>>>>> Still need the 5 V somehow, so not a complete solution for the 5680A.
>>>>>
>>>>>
>>>>> On 12/19/2011 3:06 PM, GandalfG8 at aol.com wrote:
>>>>>> In a message dated 19/12/2011 22:27:22 GMT Standard Time, caf at omen.com
>>>>>> writes:
>>>>>>
>>>>>> This  thing requires plenty of current to get started.
>>>>>> My Tek CPS250 1.2 amp  output (A+B parallel) only gets 7.5 volts.
>>>>>> Now to scrounge something a bit  bigger.
>>>>>> ---------------------
>>>>>> The 15 volts to pin 1 starts off needing to supply around 1.7 Amps,
>>>>>> eventually falling to somewhere between 700 and 800 mA.
>>>>>>
>>>>>> Pin 4 always draws around 85 to 90 mA from its 5 volt supply.
>>>>>>
>>>>>> regards
>>>>>>
>>>>>> Nigel
>>>>>> GM8PZR
>>>>>>
>>>>> Nigel
>>>>    I trust that you are aware that some models of the FE-5680A only require
>>>> the 15 volt/1.7Amp. supply.   In fact connecting a 5 volt supply to the
>>>> units that are programmable can cause damage !
>>>>    Roy
>>>>
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>>>>
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>>> --
>>> Chuck Forsberg WA7KGX N2469R     caf at omen.com   www.omen.com
>>> Developer of Industrial ZMODEM(Tm) for Embedded Applications
>>>   Omen Technology Inc      "The High Reliability Software"
>>> 10255 NW Old Cornelius Pass Portland OR 97231   503-614-0430
>>>
>>>
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