What was the root cause of the oven failure in your case? -- john, KE5FX
> -----Original Message----- > From: [email protected] [mailto:[email protected]]on > Behalf Of Chuck Harris > Sent: Friday, March 19, 2010 9:58 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] HP 5065A rubidium lifetime > > > When my 5065A had its oven failure, it got so hot that it melted > all of the > solder joints on the lamp board. I resoldered the joints, > rewound the oven > winding, and foamed the unit with some spray can urethane (Great > Stuff), and > had it working again for a couple of years. Then something else failed. > > I'd sure like to fix it, but Scott McGrath, representing himself as an > employee of Harvard University, borrowed my manual more than a year ago, > and refuses to return it. Oh well! > > -Chuck Harris > > John Miles wrote: > > One big favor you can do your 5065A is to check the ESR of the > electrolytics > > on the A11 oven driver board. C23 and C24 were open on mine, as was the > > other instance of the same 20 uF cap on the battery-charger > board, and the > > lamp driver assembly had experienced overheating to a point that was > > sufficient to char a resistor and crack it open. I'm not sure > how, or if, > > those two caps would cause total control-loop failure, but there was > > apparently nothing else wrong with this unit that could explain the > > overheating. > > > > -- john, KE5FX > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
