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Re: LA1K LDMOS died while operating 10M


 

Sorry to hear that Frank. Not sure. I have a lot of contest hours on my amp and been rock solid knock on wood. I made over 1500qso¡¯s on 15m past weekend with full 1kw out and usually run the ssb contests this way rock solid amp. However, I have had a capacitor go on mine with 200w out scenario similar to yours. Hard to say what it is without further diagnosis, but I will say with solid state amps that are fairly new, things can happen. I have an Anthem solid state home theatre amp that lost its front channel for no real reason other than it being new. It went during the first year of use, luckily was under warranty. Sometimes things just happen for no good reason. My belief is, use the new piece of electronics as much as you can while under warranty as an old rule of thumb is, if something is on the edge, it will go within the first few hundred hours of use. If it doesn¡¯t go, then chances are it is a solid unit with all the ¡°bugs¡± worked out and anything that was weak would have shown its true colours. That¡¯s the layman¡¯s non technical theory I have for whatever it¡¯s worth.

The good thing is, your shipping cost to the repair depot won¡¯t cost as much as I had to deal with. (Being a Canadian and our dollar is weak at this moment). So you have that going for you. And since my repairs on both units, many hours on them since and hoping I¡¯m past that break-in sort to speak with many more hours of rock solid performance. Hopefully it won¡¯t be anything more serious. Keep us in the loop as to how it goes for you. I have had nothing but good things to say about Palstar and their group of people. They have been good to me. Best of luck.

73
Barry
VE6UM

On Mon, Oct 28, 2024 at 18:41 Frank W4TG via <fstein=[email protected]> wrote:
I was operating the CQWW SSB contest yesterday on 10M.? My SWR is fine on that band, as shown my by almost 100 Q's before having a problem.? Then it just went into bypass mode and when I reset it to operate, it put out perhaps 200 watts.? This has happened before and Palstar replaced one of the LDMOS.
My antenna is a fan dipole up in the trees and the wind was blowing, so conceivably the swr could vary over time, but the amp has high swr protection that would cut off xmit if the SWR went above 2:1, I would think.???
Anyone else have an LDMOS failure and what did you determine caused this problem?? How did you prevent it from happening again??
I'm new to solid state amps, so wonder if this is to be expected compared to old tube amps.
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Thanks,
Frank
W4TG
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