Thanks, Here's the measurements. Note: the transistors are quite close to the board, so I had to figure out which adjacent pad to tap; I think I have measured correctly.
The DC Voltages at Q18 are: Point Measured Chart ----- -------- ----- Gate: 0.00 -1.0 Source: 3.19 2 to 3 Drain: 8.02 6.3 ! Q16: Point Measured Chart ----- -------- ----- Emitter: 0 0.0 Base: 0 0.6 Collector: 7.98 2.2 !! T5 is correct according to the diagram on page 55; leads 1 and 3 come from the top of the core and leads 2 and 4 come from the bottom, and I think that being so, the green winding cannot be reversed. On Tue, Nov 14, 2006 at 03:56:31PM -0500, Don Wilhelm wrote: > David, > > The PLL Reference is apparently OK and your problem is in the VCO itself. > The lack of RF voltage says the circuit is not oscillating - but we cannot > declare Q18 dead just yet. > > OK, next step is to check the DC voltages at Q18 - compare with the DC > Voltage chart in Appendix E. > > Double check T5 against the diagram in the manual page 55 (leads 1 and 3 > should come from the top of the core and the green winding must be in the > same direction as the red winding) - if one of the windings is reversed, the > oscillator will not oscillate. > > Check the voltage at the drain of Q17 and compare with the DC voltage > chart - measure the gate and source while you are at it, and just for a bit > of additional information, check the DC voltages at Q16. > > Tell us what you find. > > 73, > Don W3FPR David Dawson _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
