If the “723” doesn’t fix it, call Astron. They don’t have much of a customer service department, but the guy who answers the phone will sell you a replacement “control board” for $20.00 plus $7.00 shipping. Assuming the diodes and caps are still good.
Sent from my iPhone ...nr4c. bill > On Mar 11, 2019, at 8:04 AM, Charlie T <[email protected]> wrote: > > 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: [email protected] <[email protected]> On > Behalf Of Mike K8CN > Sent: Sunday, March 10, 2019 8:25 PM > To: [email protected] > 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:[email protected] > > 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:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
