Good comments. Indeed I will order up a new xtal from digi-key. They should be in stock any day now. I do agree with the comment on the cap in parallel. I had not thought about the series cap dropping and there is a .1uf as I recall. Need to look. The varicap seems to work very well so don't believe thats an issue. Will do some more hunting. By the way as a heads up the top and bottom cover of the xtal compartment are actually a pain to screw back together. Anyone have a sense of the Hz change per degree C? Thanks
On Fri, Jul 26, 2013 at 8:52 AM, Bob Camp <[email protected]> wrote: > Hi > > Ok, since it's moved *down* and it's about on temperature there are a > couple of likely possibilities: > > 1) The crystal leaks and there's air in it > 2) The trap coil(s) / capacitor(s) have changed value > 3) The varicap is shorted / forward biased > > Normal factory troubleshoot (after checking the varicap) would be to swap > the crystal and see if the problem follows the crystal or the oscillator. > Yes, I know, that's not very helpful in this case - sorry about that. > > Bob > > On Jul 25, 2013, at 9:32 PM, paul swed <[email protected]> wrote: > > > Well lucks not so good do have the voltage closer but as Bob C said. That > > ain't the issue. > > Darn I hate when he is right. By the way the oscillator draws 26 ma > approx > > as a reference. Reassembled everything and let the oven heat up it > settles > > at 81C 15 min after start and within a respectable range of the temps > > listed in the service manual. Measured with a K thermocouple. Freq is at > > 9.999955. or 45 Hz low > > Tuning the variable cap has 20 Hz range and the cap was pretty much > center > > range. Have not played with the varicap but that should have a very small > > effect. > > I can easily adjust the temp setting R to raise the xtal temp. But that > > seems like a jerry rig. > > Could a xtal of this quality simply go bad over time? > > Somewhat at a loss here. > > I have a spare 10544 (Would not use the z3801 outer oven)and wonder if at > > least I could use that with the Z3801. Anyone know if the efc would work? > > Regards > > Paul > > WB8TSL > > > > > > > > > > > > > > > > > > > > > > On Thu, Jul 25, 2013 at 10:28 AM, Stefan Heinzmann > > <[email protected]>wrote: > > > >> paul swed wrote: > >> > >>> I can't believe you found the transistor. When I pulled it out last > night, > >>> its actually a MPSA18!!! I had not had time to look it up but figured > it > >>> was a ebay leftover hunt. :-) > >>> At that price I may order 20 of them. Like the gain. > >>> > >>> Toshiba used to make a transistor with even higher gain, the > >> 2SC3112/2SC3113/2SC3295/**2SC4666 (same chip, different package). They > >> discontinued it recently, however. > >> > >> Cheers > >> Stefan > >> > >> > >> ______________________________**_________________ > >> time-nuts mailing list -- [email protected] > >> To unsubscribe, go to https://www.febo.com/cgi-bin/** > >> mailman/listinfo/time-nuts< > 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. > > _______________________________________________ > 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.
