Don, Thanks for your reply. It's great to get feedback here so quickly, especially as I managed to delay my question until a weekend.
I understand the section of the manual regarding 10 volts at TP5. What I meant to indicate is that I cannot get anywhere near 9 or 10 volts at TP5 following the normal alignment procedure, regardless of whatever setting the input attenuator is at. I've followed the procedure by the manual, carefully, many times. Despite repeated passes through the peaking process (many more than three or four, I'm afraid), I cannot get over 15 watts output or over 7.5 volts at TP5 regardless of the input attenuator setting. I've since checked the coils to be sure I have the correct ones in the filter. K3 is set up for 1.00 power out, as instructed. The fact that the overload LEDs are lighting up at the high end setting of the input attenuator leads me to believe that the IF in from the K3 is ok, and that both pre-filter amplifier stages are working as intended. Adjustments of FL1 and FL2 are smooth and have a clearly identifiable peak, leading me to believe those are ok. I'm not seeing any voltage changes elsewhere in the transmit chain, and the rest of the device voltages look good. I made several attempts at alignment since your email, with no more success than earlier. As I am concerned that the PA module may be flaky, rather than fry the thing by continuing to tune, it's going back to Elecraft on Monday for them to have a look. I'll follow up here with the results. Thanks again for your quick response. 73, Don Appleby W3MW w...@earthlink.net ----- Original Message ----- From: "Don Wilhelm" <w3...@embarqmail.com> To: "W3MW Don" <w...@earthlink.net> Cc: <elecraft@mailman.qth.net> Sent: Saturday, August 06, 2011 5:15 PM Subject: Re: [Elecraft] XV432 Issues Don, The manual doesn't state that you must adjust for 10 volts at TP5. Please read that section again. It does say that you should not exceed 10 volts at TP5 during the bandpass filter tuning. If the output goes above 10 volts, use the input attenuator R22) to bring the voltage down - perhaps in the vicinity of 5 volts, and then continue to look for the peak tuning point for each inductor that is to be adjusted. Go back over the peaking procedure 3 or 4 times. After you have peaked the bandpass filters, you will then adjust the input attenuator to produce the correct output (use an external power meter which is accurate at 432 MHz) while your selected maximum drive level is applied from your transceiver. After that (and while the transverter is producing 20 watts), you adjust R10 (Power CAL) so the LEDs indicate 20 watts. These 3 steps must be done in order - do not skip ahead or you will end up with frustration. Also, do not drive the transverter for too long at a time - particularly during the final power adjustments. Give enough "break" time to let it cool between adjustment trials. 73, Don W3FPR On 8/6/2011 3:27 PM, W3MW Don wrote: > I've just finished assembly of the XV432 kit, interfaced to a K3, and ran > into two issues during alignment in Part VI, Filter Alignment. > > First, during CW key-down, the voltage at TP5 peaks immediately, then > slowly drops off until it is a volt or more lower than peak. Immediately > re-keying gets a somewhat higher voltage than at un-key, but not at the > peak. Letting it sit a minute or two, then re-keying, gets the original > peak voltage back. Output power does the same fade. > > Second, the 28 MHz filters don't seem to be aligning properly. I've set > the cans at the set-points in the manual, but L15 and L16 seem to peak > with the slugs out of the cans. L17 appears to peak ok, and the 432 > filters both seem to peak fine. At the best point of alignment, I am > getting less than 7 volts at TP5, vs, 10 required for full output. I've > checked the K3 output, and the BNC cables, both are fine. The input > section of the XV is easily able to overdrive the input to the 28 MHz > filters, as evidenced by D10 and D11 lighting up at roughly half setting > on the input attenuator. Max output from the PA is around 15 watts > without lighting up D10 and D11. I've pulled and checked the five caps > around the filters, all are within tolerance. Oscillator alignment was > fine, 3v at TP1. I've tried re-aligning these three cans several times, > including bottoming out the slugs and working back up, with no change. > > I'm on the air with it at the moment, and it seems to be working other > than the low power output. > > Any thoughts? > > Don W3MW > ______________________________________________________________ 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
