On 1/8/2011 10:44 PM, Brian Handy wrote: > Hi All, > > I've been working on my K2 and I'm on the home stretch. I had to dabble a bit > to find a cold solder joint in the Part II checks, but eventually got a > home-brewed test oscillator to reach through on 40m! Quite happy with things > so > far, and learning a lot. > > I still have a lot to learn about the transmitter side though, that doesn't > work. When I first hit 'tune' in the Part III checks, I noticed high current > on > the power supply, high current on the front panel, and changing the power > level > didn't help, it was always high draw. > > It didn't take much of this to zorch the PA finals and short things straight > to > ground. Nothing worked until I pulled T3, and while I had the soldering out I > took out the PAs and started looking around and reading the mail archives. > > I noted one suggestion from Don to someone else and checked the voltages on > base > on the finals - both are around 0.65V, which I think is OK. > > I realize things won't be quite the same without the PAs there and proper > feedback happening, but ... I then started going through all the voltages on > the > RF board with TUNE on. Everything looked pretty much fine except for Q24 ~ > > Leg - Expected - Measured: > G - 0V - 5.6V > S - 1.2 - 2.5V > D - 13V - 0V > > That doesn't look right at all to me. Exploring further, I started chasing > VALC > down the rabbit hole. > > Pin 2 of U8 (V PWR) seems to vary between 3.8-5V as I turn the PWR knob in > TUNE. I decided that was OK. > > Pin 1 of U10A doesn't move around a lot, only up and down about 0.1V. Finally > the emitter of Q8 (V ALC) seems stuck at 7.4V. > > I was firmly confused at this point, so went back and started checking Control > Board voltages per the page of expected readings in the back of the manual > with > CAL FCTR turned on. Everything seems turned off when I do that and I'm seeing > pretty much 0V everywhere. > > I'm a bit saturated at the moment, but thought I would ask if this sounds like > I'm on the right track, or if I have to get to poking elsewhere ... > > > > Cheers and thanks in advance, > > Brian Handy > AE7JW > Tokyo, Japan > > > > ______________________________________________________________ > 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 > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net
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