I think I've had as many shorted-out tants as dried-out electrolytics. It's just that they appear in 80s gear instead of 60s. Then there was the flood of high-esr electrolytics from when - early 2000s ?
On Sun, Feb 24, 2019 at 1:10 PM Rice, Hugh (IPH Writing Systems) < [email protected]> wrote: > Several people have asked about the Len Cutler ban on Aluminum > Electrolytic Capacitors in HP Frequency Standards. Rick Karlquist could > shed more light on this too. The legend of the ban was passed along to > me, perhaps by Lou Mueller, who liked to tell stories of the old days. In > 1985, we were not taking the ban literally. For example, the 2400uF main > power supply filter capacitor was AL-Electrolytic, as were a few other > smaller capacitors on the power regulator. I sidestepped the capacitor > issues on my simple battery charger by not having a filter cap after the > transformer/full-wave-bridge, and just used 120 Hz pulses, since the > battery didn't care about DC vs. pulsed DC. (I thought it was pretty > clever to leave out the main filter cap.) Where possible, Tantalum > capacitors were used. For the few places where AL caps were used, they > were heavily de-rated, operating at 50% of rated voltage for example. > > As one reader pointed out, back in the 1965 when the 5060A was developed, > AL-Electrolytic caps were likely a lot less reliable than in 1985 when I > worked on the 5061B. > > > From: time-nuts <[email protected]> On Behalf Of Rice, > Hugh (IPH Writing Systems) > Sent: Saturday, February 23, 2019 8:49 PM > To: [email protected] > Subject: [time-nuts] HP Stories: An architectural view of the HP 5060/5061 > and awkward oscillator adjustments. > > Hello Time-Nuts, > > .... Stuff deleted ..... > > > It was fantastically reliable. Only linear power circuits, with robust > heat sinking of all power devices. The legendary Len Cutler ban on aluminum > electrolytic capacitors. 5060s were still in use in 1985, after 20 years of > constant operation. Likewise, 5061As were abundant in time standards for > 25+ years until they were replaced by the 5071A in the 1990s. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
