Thanks for the quick reply, John. > From: [email protected] > Okay, 12V on the oscillator (pin 3) and 20V on the oven (pin 14). How much > on the oven controller, pin 8?
+12V. The oscillator uses the same supply as the filter, with the addition of a 10mH inductor + decoupling caps. > Are pins 2, 4, 5, 9, and 15 grounded? Pin 6 (EFC) should be grounded for > initial testing. Yes and yes. Upon looking further, something jumped out at me: the output is 2.2V RMS into 1000 ohms instead of the 1V RMS spec'ed in the datasheet. So I suppose the problem might be in the AGC circuitry, instead of the output emitter follower. It doesn't look as though the AGC in this oscillator contains a trimpot, like the 10811 does. I'm using the schematic at http://www.leapsecond.com/museum/10544/10544-3.gif, but I don't have a good idea of how that AGC works. --n > From: [email protected] > To: [email protected] > Date: Fri, 15 Jan 2010 15:06:42 -0500 > Subject: Re: [time-nuts] HP 10544A with dodgy output? > > Okay, 12V on the oscillator (pin 3) and 20V on the oven (pin 14). How much > on the oven controller, pin 8? > Are pins 2, 4, 5, 9, and 15 grounded? Pin 6 (EFC) should be grounded for > initial testing. > > John WA4WDL > > -------------------------------------------------- > From: "Nick Foster" <[email protected]> > Sent: Friday, January 15, 2010 2:53 PM > To: <[email protected]> > Subject: [time-nuts] HP 10544A with dodgy output? > > > > > Hi all, > > > > I've just built a GPS-disciplined oscillator built around a 10544A, > > somewhat in the style of the Brooks Shera unit, just to use around the > > shack. Problem is, now that it's wired up, I notice the output is heavily > > distorted. It's clipped on the negative side of the waveform, like an > > emitter follower without enough headroom. The more I load the oscillator > > output, the heavier the clipping. When I load the oscillator output with > > 1000 ohms, spec for this unit, almost 30% of the waveform is clipped on > > the negative side. If I don't load it at all and just put a probe on the > > output, it looks OK, but still some flattening of the bottom half of the > > waveform. > > > > I've got it wired up according to the datasheet, with +12V on the > > oscillator and +20V on the heater. The grounds for the > > oscillator/amplifier, oven controller, heater, and output are all tied > > together. > > > > I know these are old units, and I'm wondering if this is a problem (for > > instance in the output emitter follower amp) that others know about, > > before I tear into it looking for a solution. > > > > Thanks for your time, > > Nick > > > > _________________________________________________________________ > > Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. > > http://clk.atdmt.com/GBL/go/196390709/direct/01/ > > _______________________________________________ > > 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. _________________________________________________________________ Hotmail: Free, trusted and rich email service. http://clk.atdmt.com/GBL/go/196390708/direct/01/ _______________________________________________ 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.
