OK gang, I don't know what to do at this point and you're my last line of defense before sending this rig back to Elecraft engineering for analysis.
I'll sum it up briefly: This is rig #2730. I bought it in kit form, and assembled it myself. It has a sub receiver, 100w amp, KDVR3, KAT3 tuner, transverter, plus a full complement of filters on both receivers. I also have a single general coverage receive module installed on the sub receiver. This is the problem: I've noticed that when I'm tuning around 4.8 MHz to 5.3 MHz, I can hear EMI in the form of a motorboat sound whenever I turn a front panel knob. It's most apparent when spinning VFO A or VFO B knobs, but also occurs when turning the filter knobs. If I don't touch anything, no noise occurs. I can also hear this noise faintly when I'm around 3 MHz. There is no front-panel generated noise anywhere else from .5 to 54 MHz other than 3 and 5 MHz. Also, if I don't have the sub receiver on and I'm only listening to the main receiver, the EMI noise isn't as loud when the pre-amp is on. If I turn the pre-amp off, the EMI generated from spinning knobs increases in volume. When I spin a knob and hear this noise, I can also see the S-meter move in correlation with the noise; spiking at S-7 from time to time. This tells me that this is locally generated interference, and occurs somewhere within the K3's circuitry. Turning the pre-amp on or off has no effect on the sub-receiver; the noise is still present. Here's what I've done: I've replaced the SUBIN board because I thought it was only the sub-receiver being affected at one time, but it didn't help. I've also swapped mixers and synthesizers with no positive result. I've disassembled and reassembled the entire front panel 4 times already, and cannot find anything wrong. I've traced circuits on the sub receiver and SUBIN boards and everything checks out. I've also swapped TMP cables around with no improvement. I've also removed just about every module except the transverter and KAT3 hoping to eliminate a problem module, but the problem still remains. I've also checked every screw and washer throughout the radio, and they all match the assembly instructions. I'm starting to think that there may be an isolation problem with the main RF board at this point. BUT, since I was not able to test the rig without the KAT3 tuner or removing the transverter board, I cannot be 100% sure. Is there anything else I can check before sending the rig back to Elecraft??? Apart from this problem, I have not experienced any other issues with this radio. In fact, it works PERFECTLY well.. I should probably tell myself to live with this noise, but after spending 4k, I don't want too. Suggestions people? Please help a fellow ham out. 73, James KC2UEE ______________________________________________________________ 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
