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 > -----Original Message----- > > I read 12098.20 down to 12084.54 at TP3 in the PLL Reference Oscillator > Range test. > > I checked the windings of T5 very carefully, as well as the resistances > between pads - they appear correct. > > The soldering at T5 and Q18 looks good. > > The RF Voltages at Q18 are all zero :-( ... Dead? > > DC Voltages at U3: > Pin 6: 4.02 > Pin 7: 8.02 > Pin 8: 0.00 > > RF Voltages at U3, Pin 3 & 6 are all zero :-( > > On Tue, Nov 14, 2006 at 07:24:04AM -0500, Don Wilhelm wrote: > > David, > > > > Do you read a proper frequency at TP3? Does the PLL Reference Oscillator > > Range test produce the correct frequencies? (see the manual page 60). > > > > If the answer to the above question is YES, then check the > winding of T5. > > Be certain the turns are correct and the leads are inserted > into the correct > > holes. Check the tinning and soldering. Check the soldering in the > > vicinity of T5 and Q18. What are the RF Voltages that you read > at the gate > > and source of Q18? > > > > Check the DC Voltages (compare to chart in Appendix E) at U3. > What are the > > RF Voltages at U3 pin s 3 and 6? > > > > 73, > > Don W3FPR > > > > > -----Original Message----- > > > > > > I don't know. Must be asleep at the switch. > > > Here's what's what so far this end. > > > The probe verifies -- it did read correctly in step 3 on page 46. > > > The leads are correct. > > > > > > I have replaced the suspect diode but the probe will not read anything > > > at TP1. > > > > > > I have constructed the RF Probe and connected it to my DMM. > > > It reads voltages at certain points, but sees nothing at TP1. > > > > > > > > > > -- > David Dawson > _______________________________________________ > Elecraft mailing list > Post to: [email protected] > 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 > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.409 / Virus Database: 268.14.5/533 - Release Date: 11/13/2006 > > _______________________________________________ Elecraft mailing list Post to: [email protected] 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
