On Sun, Apr 18, 2021 at 5:02 PM <[email protected]> wrote: > > "When I engage OPER the input signal is attenuated by ~20 dB." > > Thanks to all for the prompt and informative replies. Apparently the culprit > has been found. Several reported the exact same issue, one as recently as > one week ago. According to one reply, an Elecraft Tech told him, "This is a > known failure mode." (Not very encouraging!) > Here is a copy of an Elecraft repair report: > > Reported problem(s): > Receive signal is attenuated when in operate. Receive signal is normal when > in standby. > > Problem(s) found: > Confirmed problem. Found that D8, D9 and R7 in the T/R circuit had failed. > > Repair(s) performed: > Replaced D8, D9, and R7 on the LPF board. > > Looks like my KPA500 is in for some "belly up" treatment! > One thing has me a bit puzzled though. If this is a known weakness, why > hasn't Elecraft designed a "beefed up" mod? My amp had 5 updates / mods done > while it was at the factory. This "known failure" was not one of them.
There definitely has been "beefing up" of the T/R circuit over the years. I don't know about dates. You might find this interesting (although I think your failure is different - I've been "lucky" enough to experience both, and more): http://ok1rp.blogspot.com/2017/02/elecraft-kpa500-lpf-tr-switch-rework.html Mine when back in late 2019, and had the following performed (amongst other fixes and updates): "Replaced Q5, D7, R3, R9 and R24 for Transmit/Receive MOD (Improves robustness in Transmit/Receive circuitry)." Good luck getting a response from Elecraft support now. Apparently they don't respond to email any more (mine from April 5th has been ignored so-far, and I've seen similar reports from others here). 73, ~iain / N6ML ______________________________________________________________ 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]
