I'm sure you could invent many ways to protect these parts (gas tubes, sacrificial TVS diodes, fusing, etc.). The best way, of course, is to disconnect it (which of course I did not do). These are low voltage parts on the receive side path so I don't know if a gas tube would be appropriate here... Someone with more experience with them can chime in here.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ email: b...@wjschmidt.com -----Original Message----- From: CUTTER DAVID <d.cut...@ntlworld.com> Sent: Saturday, June 5, 2021 10:46 AM To: b...@wjschmidt.com; Elecraft Mail List <elecraft@mailman.qth.net> Subject: Re: [Elecraft] KPA500 receive loss Would a gas discharge tube save the sensitive parts? David G3UNA > On 05 June 2021 at 16:20 "Dr. William J. Schmidt" <b...@wjschmidt.com> wrote: > > > This happened with my backup amp at the contest station on J6. I left > it connected by accident overnight (too much rum) and we had some > static storms. Took out the pin diodes (well, more accurately the > diodes that act like PIN diodes). When put in operate, the receive > drops by 30+ dB but still transmits fine. A simple replacement of the > four diodes and three (?) transistors solved the problem. Dirt cheap. > You can make these measurements at the test-points to confirm: > > > TP2= RX 13.1, TX 0.8 > TP4= RX 3.9, TX 13 > > > Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ > PJ2/K9HZ > > email: b...@wjschmidt.com > -- This email has been checked for viruses by AVG. https://www.avg.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 Message delivered to arch...@mail-archive.com
