Eric Webner <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- Someone once told me that it is easier and less expensive to replace a transistor in a crystal oscillator circuit than it is to replace expensive crystals that won't oscillate.
I think you are on the right track. 73, Eric KA8FAN --- neil <[EMAIL PROTECTED]> wrote: > > neil <[EMAIL PROTECTED]> made an utterance to the > drakelist gang > ---------------------------------------------------------------------- > Dennis Monticelli wrote: > > > > "Dennis Monticelli" <[EMAIL PROTECTED]> > made an utterance to the drakelist gang > > > ---------------------------------------------------------------------- > > Normally, I would not expect a small-signal > transistor to experience > > much drift in its characteristics with time. It > is possible but not > > likely. Perhaps the bias point has shifted due to > resistor drift or > > some other factor. If it is not running at the > current it should that > > could easily explain the problem. I would check > that before replacing > > the transistor. > > Thanks for the reply. > > DC voltages appeared reasonable, so lacking any > other ideas, I went > ahead and swapped the transistor. I used a > garden-variety 2N3904, which > specs seemed to suggest was only slightly hotter > than the original > 2N3394. > > For whatever reason, that seems to have cured my > problem - the > oscillator starts right up on all five crystals (80 > - 10). The RF > voltage at the mixer grid ranges from about 1.5v on > 80 meters down to > about 0.8v on 10 meters. > > I confess that in these solid-state days, I've > forgotten so much about > vacuum tube theory that I don't know what RF voltage > I should be seeing > on the mixer grid (with a scope) - any idea? > > 73 > > Neil > KX2Y > ---------------------------------------------------------------------- > Submissions: [email protected] > Unsubscribe: [EMAIL PROTECTED] - > unsubscribe drakelist in body > Hopelessly Lost: [EMAIL PROTECTED] - > help in body of message > Zerobeat Web Page: www.zerobeat.net - sponsored by > www.tlchost.net > ---------------------------------------------------------------------- > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ---------------------------------------------------------------------- Submissions: [email protected] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net ----------------------------------------------------------------------
