Good idea...I'm at that stage where I need to check parts and try to isolate. The receiver and all works well. Thanks, Chuck, KE9UW
---- Original message ---- >Date: Wed, 21 Oct 2009 08:42:52 -0400 >From: Don Wilhelm <[email protected]> >Subject: Re: [Elecraft] KE8UW Re: Just finished K2 and finals look to be >oscillating at 450KHz... >To: [email protected] >Cc: elecraft <[email protected]> > >Chuck, > >Since you have a 'scope, I would suggest you remove the PA transistors >from the picture and see if the oscillation persists. You can easily >de-solder T3 which will remove voltage from the PA collectors. >If you still have the oscillation at the base of Q7/8 (or at the >collector) of Q6, then you can more easily troubleshoot it without fear >of damaging the PA transistors. >Q6 can similarly be taken out of the operating condition by removing a >choke or resistor. I don't have the schematics with me while on >vacation, so you will have to find out which one on your own. > >73, >Don W3FPR > >C. J. Hawley wrote: >> Yes the W6 point gets 8 volts either thru the diode D2 or D6 depending on >> whether in receive or xmit. I think I have an oscillator at Q5-Q6. I am >> checking all the feedback chokes and capacitors. I may need to unsolder C118 >> and see if it is infact a capacitor inside the shell and maybe also C120. >> RFC6 checks ok, R49, R470, etc. >> Thanks for the interest and help. >> >> Chuck, KE9UW >> >> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
