Topband: YCCC 9 Circle preamp failure

[lloydberg at charter.net]

I'm running the YCCC RX array. I had to add 100K carbon resistors
between the input terminal and ground as a static drain or the input
caps would puncture and burn out the Integrated Circuit.
73
Lloyd - N9LB 

	-----------------------------------------From: "VE6WZ_Steve" 
To: "topband"
Cc: 
Sent: Friday September 13 2019 2:10:48PM
Subject: Topband: YCCC 9 Circle preamp failure

 After 2.5 years of flawless operation, earlier this summer my YCCC 9
circle rx array started to develop some strange inter-mod noise, and
random junk showed up on 160m when using the array.

 I isolated the problem to be the .1 uF coupling capacitors on the
input of the amps. This happened on 4 of the 9 amplifiers.
 The most likely cause is from TX overload because this array is only
about 125’ from my parasitic TX array. (the TX antenna is detuned
when on RX and presents no issue on receive).
 At first I suspected a nearby lightning strike, but the 4 failed amps
happen to be the closest to the TX array, nothing else in the amp was
damaged, and there was no other evidence of a lightning event at the
station.

 Here is a link to a YouTube video I made showing how I isolated the
problem. Using my scope I show how the output from the damaged amp has
significant phase and amplitude distortion, and using the multimeter
the failed caps are evaluated.

 https://youtu.be/t6oux3MStDw [1] 

Links:
------
[1] https://youtu.be/t6oux3MStDw
[2] https://youtu.be/t6oux3MStDw>
https://youtu.be/t6oux3MStDw>
 /> 
 If you have one of these arrays, I show how it is very easy to test
the pre-amps in the field using your multi-meter to confirm if a
similar fate has occurred in your system.
 
 73, de steve ve6w
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