Thanks Don. Having looked at it again it does actually look as if the output from the K2 transverter socket is missing or very low. I got a bit confused about levels (as well as making typos) and I should most definitely be able to see the 1mW on my scope (632mV p-p). I did have to tighten up the locknuts on the phono sockets at the K2, maybe there is an open circuit or short circuit there as well. Will take the K2 apart again later and check, but the XV50 is probably OK.
73 Dave G3YMC On 20 Nov 2015 at 14:28, Don Wilhelm wrote: > Dave, > > Be cautious with conclusions when probing with a 'scope probe in the 50 > MHz section of the XV50. The probe can pick up RF and produce false > output indications. The fact that you can induce output by probing C48 > does normally indicate that U6 and U7 are capable of producing a signal. > Check the LO signal. If that is good, then the problem may be in the 28 > MHz bandpass or the mixer. > > I am puzzled by your reference to 5mW. The K2 with the K60XV has 1mW > output - was that a typo? > > If you want to probe the 28 MHz IF in the XV50, you can re-plug the > transverter for up to 5 watts input and you should be able to follow the > signal path through the 28 MHz bandpass filter - all the way to the > mixer input. > > If it works with the high level input, then try the low level input > again - the 1mW input removes the attenuator and adds the gain of the Q6 > stage. > > 73. > Don W3FPR > > On 11/20/2015 11:22 AM, Dave Sergeant wrote: > > My XV50, which worked fine for this summer's sporadic E season, has > > suddenly gone faulty and has no output in either CW or SSB. The input > > from the K2 is present, although of course 5mW is pretty hard to > > measure accurately with my scope. There is also no signal at the input > > of the power amplifier module, but if I connect my scope probe to C48, > > at the output of the bandpass filter, and key the rig I have more or > > less correct output and a good 50MHz sinewave on the scope - as soon > > as I remove the probe the output disappears again. So the output > > module is fine and the fault would seem to be related to the U6 buffer > > or the bandpass filter. I am a bit mystified and need to sit down and > > work out what is really happening. > > > > > http://davesergeant.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
