[time-nuts] 5070B once more.... (actually 5370A fans)

David Forbes dforbes at dakotacom.net
Fri May 22 17:42:15 UTC 2009


At 10:13 AM -0700 5/22/09, Tom Van Baak wrote:
>One comment, and one idea on airflow...
>
>
>I'm sure we could discuss for some time what airflow is too much
>or too little or where to place the thermal probes or how to take IR
>scans or how then interpret them. But it seems to me the bottom
>line is not what the temp is inside, but how the unit performs; how
>stable the time interval counter is. voltco; tempco; airco?
>
>
>/tvb
>

Tom,

The fans in a 5370B have nothing to do with stability; if anything, 
they make it worse.

The reason for the fans is to prevent premature failures of the 
silicon devices due to thermal degradation. The life of a silicon 
chip is halved for every 10C temperature increase, more or less.

In a world of perfect thermal engineering, the chips would be 
attached to a metal plate that is kept at a constant temperature. But 
that's impractical for cost, weight and maintenance reasons.

Given that many of these ECL chips are no longer made, keeping them 
cool for long life is of utmost importance.
-- 

--David Forbes, Tucson, AZ
http://www.cathodecorner.com/




More information about the time-nuts mailing list