Brett Welcome to the group. If you do not have a pdf of the 5328 manual go here to get a copy. http://www.ko4bb.com/manuals/index.php I had several 5328s a long time ago and they are quite nice counters. Looking at the schematic there is indeed a tstat that controls a SCR that runs the fan. Now its not clear to me what resistor might be smoking. There is a .47 ohm resistor for current sensing. If thats smoking you have a short or something. But thats speculation. Take a look at the schematic and let us know what R is smoking. That may help us a lot. To the fan 12 vdc or such it could work but they may draw a fair amount of current and do generate noise that may possibly effect low level readings. So certainly can work. Regards Paul WB8TSL/1
On Fri, Jan 17, 2014 at 6:03 PM, Brett Owen Rees <bre...@gmail.com> wrote: > 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 > > > -- > Mobile: +61 468 512095 > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.