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RM Italy KL 7405V 10 meter Linear Amplifier With Fan

Had a new 7505 a while back. With proper input drive, it sounded like a raspy class c box. Maybe the bias circuit was misadjusted or faulty. And lots of RF was floating on the DC power leads flipping my Astron out. The schematic shows .01 caps but no chokes on the power leads.
 
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I have a KL-7505V with 2 fans. I had to do a fan mod so they are on all the time.I have it under the bench and it's a little better. Modded for 11 meters. works great no problems and will do 200 watts out. sounds good on ssb and am. don't over drive it. Had it for 2 years or so now.
 
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Mine is OK. I run it at 25 watts carrier and around 125 pep. It doesn't seem to need a fan. :)

Linearity starts to suffer after 150 pep so keep it below that.

That's close to how I ran my 7405. Mine will shut down until it cools off. It only does that when I flap my Jaws for extended periods. Just regular use, it works fine. I wish I'd had got the bigger one.
 
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73's I have a 7505v and i have the Temp shutdown problem. I only use it on SSB and I can't talk more than 2min and it will go on protection mode (TX LED BLINKING) the funny thing is that the amp is not even hot. I contact the company I got it from and they send me a replacement and is doing the same exact thing. It will do it with 3 different radios, 2 antennas with different coax, even with antenna tuner and dummy load. My SWR is lower than 1.2 with the AMP. Is there anything I can do to prevent the overheating protection to do what is doing, maybe re-calibrate or adjust the temp shutdown. H E L P !!!!!!!! Thanks
 
Did the place you bought it from solder in the jumper so it will work on 11m?

I would take the lid off and touch the transistors when it goes into thermal shutdown. If they are hot and the heatsink is cool they may have forgotten to put the pookie under the pills.

I don't know if the thermistor for the thermal shutdown is actually on the heatsink or laid across the top of one of the transistors. If it's on top of a transistor and they forgot the heatsink compound that would explain it.
 

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