[time-nuts] HP 5372A Fan

[Ed Palmer]

Now that you mention it, I don't think I confirmed that the voltage to 
the fan was higher.  I just assumed that it was.  I'll have to redo that 
test.

Ed

Pete Rawson wrote:
> Ed,
>
> From your description of the fan noise, I have one concern.
> If the fan speed seems to increase without a good cleaning 
> or change in the supply voltage, then it's likely that the airflow
> has been decreased, an obvious speed up is not good news.
>
> Pete Rawson
>
> On Mar 9, 2010, at 10:44 PM, Ed Palmer wrote:
>
>   
>> I have a question for owners of the HP 5372A (and probably 5371A) Time Interval Analyzer.
>>
>> Is the fan on the back blowing out or sucking in?
>>
>> I was looking at mine to see about replacing the fan with a quieter one and I was surprised to see that mine is sucking in.  This doesn't make sense to me for two reasons:
>> 1.  It blows hot air out the front and bottom straight at the operator.  Uncomfortable on a hot day.
>> 2.  Just inside the unit at the back on the motherboard there's a temperature sensor that controls the fan speed.  Why would you blow cool outside air over the temperature sensor?
>>
>> It would seem to make more sense to have the fan blowing hot air out the back and drawing the hot inside air over the temperature sensor.  I experimented with this configuration and found that the noise level went up because the fan was turning faster - no big surprise there.
>>
>> I can't find any info in the manual (service or operating) about this.
>>
>> Ed
>>
>>
>>
>>
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>
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