About the HP5370 please got o see my solution to: http://www.timeok.it/files/hp_5370a_temperature_solution.pdf
Luciano timeok see : www.timeok.it On Fri, Jun 14, 2013 at 4:26 PM, Mark C. Stephens <ma...@non-stop.com.au>wrote: > Talking of Cooling HP 5370's, I have a 12V fan Gorilla taped to mine fed > from a wallwart. > > Not elegant, but it has reduced the heat sink temperature dramatically. > > Is anyone else concerned about the heat sink temperature on the 5370? > Has anyone done a fan modification they would care to share? > > Also, my 8566A RF section pass transistor heat sink gets awfully warm too, > does anyone have a sensible solution? > > > -marki > > > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of David Kirkby > Sent: Friday, 14 June 2013 7:14 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] HP and other equipment failure > > On 14 June 2013 05:48, Perry Sandeen <sandee...@yahoo.com> wrote: > > > There are two long standing truths about electronic equipment. One > > you can't have too much filter capacitance. Two, you can't cool too > > much. (Please spare me the liquid nitrogen or submarine battery > > comments.) > > > > Regards, > > > > Perrier > > Well, I have to disagree with both comments. > > More filter capacitance in a standard linear power supply means the diodes > take more current for a longer period of time. For any given diode, that > puts more strain on it. At very high levels of capacitance, the amount of > stored energy is huge, and can be dangerous. In the event of a fault, > higher stored energy has the potential to do more damage than lower stored > energy. Once you have sufficient capacitance, which includes calculating > the effects of reduced supply voltage, minimum capacitance of device with > tolerances, and some safety factor, I don't see what more capacitance does > other than increase costs, weight, and the potential for more damage in the > event of a fault. > > Whilst it is well known that increasing temperature gives rise to shorter > component lifetimes, more cooling also requires more noise, and so a > compromise has to be met. I have here an Air Control Industries VBL9 > blower, which I want to sell in fact. That will move about 1000 cfm at 6" > of water pressure. It happens to take 2.8 kW from the mains, the startup > current is too large to not blow a normal mains fuse in a plug here in the > UK, and the noise is enough to get neighbours wondering what the hell it > is, despite I live in a detached house, some 50 m from the nearest > property. So while a HP 5370B needs far more cooling than provided, I think > the VBL9 would certainly provide too much cooling air. > > Engineering is always a compromise. HP usually got that balance about > right, although in some instances, like the 5370B, that is not true. I know > mine got pretty damm hot, and I'm quite near sea level. I would imagine for > someone at a high altitude, it would be even worst. > > I have to agree with you about the serviceability of older HP equipment > though. It is much more serviceable than modern equipment. > However, you would have to go back a long way before finding equipment > which one could guarantee one could keep going, as most things I'd > contemplate buying will have a ASIC and/or some other specialist component > which if it failed would be impossible to get except by taking one from a > similar piece of equipment. > > Dave > _______________________________________________ > 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. > -- Luciano Timeok visit : www.timeok.it _______________________________________________ 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.