[time-nuts] R: HP 5328A fan - suspected issue

[iovane at inwind.it]

I had five 5328A, three military and two normal, and still own three. The fan 
runs whenever the unit is turned on and never stops. In the military version 
the fan is much noisy.
Antonio I8IOV


>Da: breree at gmail.com
>Data: 18/01/2014 0.03
>A: <time-nuts at febo.com>
>Ogg: [time-nuts] HP 5328A fan - suspected issue
>
>Hi all,
>
>This is my first post to this list. I recently acquired three HP 5328A
>counters and have been using one in my shack. They all seem to have fan
>issues, with the fans not running in two of them and in the third unit a
>resistor near the fan starts to smoke if I turn it on. All of the fans look
>identical, being 110V AC units.
>
>So, I have some questions:
>- should the fan run all of the time or is it on a thermostat
>- does the smoking resistor mean that the fan is seized
>- can I replace it with a 5V/12V computer fan. If so, can I safely tap DC
>off the power supply and will the fan introduce any electrical noise? I am
>240V here so sourcing a fan 110V fan locally may be difficult
>
>The counter I have running seems ok without the fan running. It is the pick
>of the bunch with the OCXO, 525MHz and DVM option. Being the best
>oscillator I have currently, I have checked it against WWV and it seems ok.
>I also used it as an alignment  reference for a funcube dongle receiver
>(with tcxo) and am receiving WSPR spots on frequency, so I think it is
>good. I am slowly getting the time-nuts bug and am building a GPSDO with a
>Morion MV89A ocxo ...
>
>Many Thanks es 73
>Brett VK6EZ
>
>
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