Bob - I'm sure you researched them ... which one did you go with?
73 Lyn, W0LEN -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bob McGraw K4TAX Sent: Monday, May 18, 2020 12:22 PM To: [email protected] Subject: Re: [Elecraft] An Unusual KPA-500 Failure - That Wasn’t ... I have installed a whole house surge protector on the main breaker panel. Thus everything in the house is protected equally. I don't use any surge protection devices at any other locations. My Justification: more connections, more items = more problems. 73 Bob, K4TAX On 5/18/2020 12:15 PM, Lyn Norstad wrote: > Bob - > > Having had to ship my 10 month old KPA500 back to Elecraft twice in its short > life, I was fearing the worst when I started reading your post. > > What a relief to hear the actual cause ... and I can well imagine it was > doubly so for you! > > 73 > Lyn, W0LEN > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Bob Witmer > Sent: Sunday, May 17, 2020 11:31 PM > To: [email protected] > Subject: [Elecraft] An Unusual KPA-500 Failure - That Wasn’t ... > > I thought the group might find a recent KPA-500 troubleshooting experience > interesting - and possibly be of help with future troubleshooting efforts. > > For reference, my station consists of a TS-890 followed by a KPA-500 and a > KAT-500, that interfaces different wire antennas depending on the operating > band. > > One Friday night after dinner, I headed to the ham shack to check out 160M. > Since it had been raining I needed to check the antenna SWR. After > completing a KAT-500 (KAT) tuning cycle at low power, I had a new tuning > solution and switched in the KPA-500 (KPA) for confirmation. I started at > low power and slowly increased the power level. At around 100 watts output > from the KPA I was rewarded with what I call the “Allen-Bradley” smell, a > slight cloud of smoke and a KPA low voltage alarm! I immediately cut power > and tried to reset the KPA alarm but couldn’t by cycling the power off/on. So > I unplugged the KPA from the AC power. After reconnecting the power and > turning the KPA on, the alarm was gone. I repeated the tuning process, with > almost the same results except the smell and smoke were more noticeable. At > this point I took the KPA completely off line, disconnecting all control and > RF connections, and raised the power out level of the TS-890 to 90 watts, > which then confirmed normal operation via the KAT. At this point I began to > think about returning the KPA for repair and wondered how long it would take > to get it back, considering COVID-19 issues. > > For some reason I decided to try the KPA500 - KAT500 pair one more time. > This time I moved closer to the KPA500 to try to get a clearer idea of where > the “smoke” was coming from. I slowly raised the power one more time and the > KPA shut down just like before, but this time I noticed the “smoke” was > coming from what looked like the rear of the amp. I moved the KPA and > noticed the smell was still very strong - and at the rear of the KPA. It was > then I noticed that the AC line surge suppressor the KPA was plugged into, in > a wall socket directly below the back of the operating table with the KPA, > was the source of both the smell and “smoke”. I bypassed the suppressor and > was relieved when the KPA returned to normal operation. > > Somehow, when the current draw through the suppressor reached a certain > level, failing internal suppressor component(s) overheated and presented a > line voltage drop to the KPA500 sufficient to trigger the internal low > operating voltage alarm. With the suppressor located directly behind and > below the KPA, it seemed like the smell and smoke were coming from the KPA - > and the KPA was failing since the KPA low voltage alarm activated. > > So of course, always check to make sure the equipment you’re troubleshooting > is actually “plugged-in” (following troubleshooting safety guidelines) - but > also check to make sure any in-line power surge suppressors are working > correctly. > > 73, > > Bob, W3RW > ______________________________________________________________ > > ______________________________________________________________ > 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 > Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
