K1 Power Supply Melt Down

[Tom Johnson]

I just completed my K1 RF Board through to the DC Voltage Checks section.  I
plugged into a 12 V Battery Pack and did not get any smoke from the board
when I turned on S1.  But I did not get a voltage reading from pin 15 on P1.
I did get a reading between 3.8 - 4.2 on P1 pin 16.  I went back to trying
to get a reading from P1 pin 15, and then noticed my battery pack (8 1.5 V
AA) was bubbling and melting down - very HOT!  

Does anyone have any clues as to what went wrong?  My only guess is if RFC1
(33 uH RF choke) and RFC4 (100 uH RF choke) are directional, I may have them
reversed: I thought like resistors they are not directional.

73



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[Bill K9YEQ]

Chokes are not directional.  Check your board for solder bridges and let us know what find.   Since the board is mostly discreet parts, start looking at the battery connection and work your way into the  circuitry. Is a part blackened, or very dark?

73,
Bill
K9YEQ

________________________________
From: [hidden email] <[hidden email]> on behalf of Tom Johnson <[hidden email]>
Sent: Thursday, March 14, 2019 8:34:47 PM
To: [hidden email]
Subject: [Elecraft] K1 Power Supply Melt Down

I just completed my K1 RF Board through to the DC Voltage Checks section.  I
plugged into a 12 V Battery Pack and did not get any smoke from the board
when I turned on S1.  But I did not get a voltage reading from pin 15 on P1.
I did get a reading between 3.8 - 4.2 on P1 pin 16.  I went back to trying
to get a reading from P1 pin 15, and then noticed my battery pack (8 1.5 V
AA) was bubbling and melting down - very HOT!

Does anyone have any clues as to what went wrong?  My only guess is if RFC1
(33 uH RF choke) and RFC4 (100 uH RF choke) are directional, I may have them
reversed: I thought like resistors they are not directional.

73



--
Sent from: http://elecraft.365791.n2.nabble.com/
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
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This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html