It would also be very helpful if you can find the cause of the problem inside the RS-20A. There's probably more of those particular supplies and their family than any others. I'm fairly sure they use the old reliable "723" regulator that has been around since it seems, Hertz experimented with sparks.
As an old sage used to offer a useful piece of advice....."It's probably a resistor or a capacitor or something". 73, Charlie k3ICH -----Original Message----- From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> On Behalf Of Mike K8CN Sent: Sunday, March 10, 2019 8:25 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] [K3] Spontaneous HI CUR, audio reduction in RX mode - UPDATE I may have found the cause of the anomalous HI CUR warning in **receive** mode, thanks to my big orange Maine coon cat, Mr. Opie. In rubbing his chin on the VFO B knob while I was listening last night, he rotated the control to the 12V DC bus voltage display, which I then noticed was oscillating between 13.6 V and 12.7 V. When I checked the DC bus current display, it was oscillating between 0.4 A and 2.1 A - clearly something was amiss. Tonight I checked the terminal voltage on my Astron RS20-A linear supply, and found it to be stable at 13.7 V with no load (K3 turned off), but then it dropped to 13.4 V with the K3 'on' in receive mode. I again checked the K3's internal volt/ammeter readings and found the same periodic oscillation in each one. Curious to know if the oscillation was due to an interaction with the supply regulator, I swapped out the RS20-A for my Astron SS-30 SMPS, which I normally use with my K2/100 setup. Lo and behold, the DC bus oscillations ceased! I have not yet spent enough time listening using the alternate power supply to know if the HI CUR warnings will also cease, but will do so over the coming week. Fortunately, I don't have to watch the K3 display because the HI CUR condition also reduces headphone audio substantially, which gets my immediate attention. Kudos to Mr. Opie for his uncanny sense of what might reveal a potential cause of the spontaneous HI CUR warnings in receive mode. 73, Mike, K8CN -- Sent from: http://elecraft.365791.n2.nabble.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 ______________________________________________________________ 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
