Hi Don and everyone else who responded,
The current readings @ 5W and 10W are now at the upper end of normal levels.
T4 was reversed and needed to be turned around. The power wire is also on
the thin side, 16g or 18g. I'll find a replacement tomorrow.
Two new interesting problems have cropped up as well:
a) 20m band, tuned Zepp: The S-meter is pegged on +40dB when the preamp is
on. With the preamp off, the meter settles down to around S5 (S5-S9 when
copying a signal). On 40m, antenna tuned, the LED reads +40dB with preamp
and +20dB without. Tried following the S-meter setup instructions in the
manual, including those on the XG1 mini-kit, but nothing seems to prevent
the LED from locking into the upper limit when the preamp is on. Is this
normal? The AGC can be switched on and off as well as set fast or slow. With
AGC off, the S-meter drops to zero.
b) The gain drops intermittently from an S-meter reading of +40dB to S2 with
preamp on. The audio also diminishes in intensity at the same time. The last
time it did this, I tapped the left side of the radio a couple of times and
it stopped dropping out. This sounds like a loose component, bad connection
or bad solder joint. Where should I begin my search? The IF stage? Could it
be a toroid with a bad solder joint?
Thanks,
Kathy
------------------------------
Message: 43
Date: Sun, 25 Dec 2005 01:44:48 -0500
From: "Don Wilhelm" <[EMAIL PROTECTED]>
Subject: RE: [Elecraft] K2 Alignment and Test, Part III: High current
To: "K.Kishimoto" <[EMAIL PROTECTED]>, <[email protected]>
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset="iso-8859-1"
Kathy,
I suggest that you tackle the voltage drop problem before investigating
the
current draw. What size wire are you using for the power wiring? - it
should be 16 guage or larger. Next check all the connections from the
power
supply to the K2 - they should be tight or well soldered. If no problem
is
discovered in the power supply wiring itself, measure the voltage at the
power supply output terminals under the load in transmit - compare to the
K2
display. The K2 display should show about 0.3 volts less than the power
supply output due to the protective series diode.
Lastly, check the soldering in the K2 12 volt path to be certain there are
no high resistance solder joints.
Once you get the voltage drop under control, the current should fall in
line
with what is expected. You receive current draw is about normal.
73,
Don W3FPR
-----Original Message-----
Power supply: SEC 1223 (23A)
Unit type: K2, no options installed
Passed Alignment and test, Part II
Passed all resistant checks
Baseline voltage and current (backlight on)
13.5v, 0.24A
Transmit voltage and current into Elecraft 20W Dummy load (Using TUNE
function)
At 5W: 12.7v, 1.84A
At 10W: 12.1v, 2.98A
The current draw seems far too excessive given the suggested range in the
manual. What components could potential cause this problem? The
voltage drop
seems high as well given the capacity of the PSU.
Thanks,
Kathy
*Merry Christmas!*
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