Geoff,
I did try this but it didn't solve it.
What I have found is that I was wrong in believing the CW was OK - its
not - it has a very raspy signal to it. So I will try to track that
down first.
I am confused about the behaviour of U2 on the SSB board - it seems to
take a long time to ramp up if it is setting the PWR level. However,
before I worry much more about this one, I'll try and track down my
raspy CW signal first.
73
Paul
Geoffrey Mackenzie-Kennedsy wrote:
Hello Paul,
My K2/100 (with KSB2) is about the same age as yours, and some time
ago it started to act up - going as far as shutting down completely
with just the display showing the last frequency to which it was
tuned. In my case the problem was cured by removing the MCU U6 on the
Control Board from its socket, and then putting it back again. The
type of IC sockets used in the K2 do not seal the IC pin - socket
connection, and corrosion can build up causing problems. Later, and I
am not suggesting that you do this as it is a gruesome task, I
replaced the socket supplied for U6 with a turned pin type which does
seal the connection, but was not brave enough to change all the others!
Just a thought.
73,
Geoff
GM4ESD
----- Original Message ----- From: "Paul Wilton" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, November 12, 2005 3:11 PM
Subject: [Elecraft] Problems with SSB Audio
Following some reports of bad audio (confirmed by self listening), I
have been looking at my SSB adaptor in my K2.
So far I have reached the following conclusions
a) Its not RF leakage - running with a Dummy Load still creates it
b) If I monitor the RF output with my 100MHz scope, in CW the
amplitude is clean and stable and I can change its level with the
power control pot. If I inject a single audio tone into the mic
input, then the output is cleanish but keeps jumping in amplitude -
approximate a few times a second.
c) Looking around the SSB board, I make the following observations
(with the power control pot on about 10W)
The PWR CTRL line from Pin 6 on U2 slowly rises stopping at about
5.5v after 5seconds. At the end of its rail, it "jumps" a little.
The ALC THR line from Pin5 on U2 goes instantly to the correct value.
The Base of Q1 (VRFDET) jumps around
The ALC line (Pin 2 of U1) also jumps around
It looks as if I have something amiss around the level control loop
on the SSB card. It works ok on CW.
My K2 has been working fine for a couple of years now so it is
strange it has stopped. Any suggestions where to look?
73
Paul
M1CNK
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