Scott,
I blew the final transistors on the previous model, the 509.
Sounds like you know what you are doing but I'm going to throw in something
anyway that we all know and keep trying to forget:
"IF YOU BUY CHEAP, YOU BUY TWICE."
Gud Luk.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Scott Zastoupil
Sent: Friday, February 25, 2011 10:32 PM
To: tentec@contesting.com
Subject: [TenTec] Argonaut 516 Transmit into a short - stupid
Hi All. I just did something real stupid by forgetting that my antenna was
grounded and transmit my Argo into a dead short. Now the power meter just
slightly wiggles at a power setting what once was 5W. I'll open it up and
try to trouble shoot the voltages up to the power amp and scope the driver
input and output to see if that is blown. The ALC LED does not light
either on TX with a CW key. Not sure of the criteria for that to light up.
It is very likely I toasted the 2SC3133 output transistors. I went to
RFParts.com and they call for a replacement of using a matched pair of
2SC1945. The price is a little more than I was expecting. My question is
do they really have to be matched pairs? It seems just adjusting the bias
voltage on each would be sufficient. I'm not exactly sure where they should
be biased besides have an equal collector current at idle. I see some on
ebay, but kind of leery of those being gray market parts since they're
coming from Hong Kong.
Any thought/suggestions on repair and alignment?
Scott, KB0KFX
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