Posted by
Don Wilhelm-3 on
Feb 15, 2007; 5:04am
URL: http://elecraft.85.s1.nabble.com/No-power-out-on-K1-tp443796p443797.html
Cathy,
Definitions first - RF IN and RF OUT are designation of the RF Bandpass
filter only - on transmmit the signal goes in as RF IN and comes out as RF
OUT - however, on receive the path through the RF Bandpass is reversed, so
'in' is 'out' and and 'out' is 'in' <G>.
Since you have a scope, I suggest you use it for peaking the Premix Bandpass
filters and the RF Bandpass filters on transmit. Just read the RF Voltage -
no exotic 'scope functions here - start with all the trimmers set near
mid-position - put the probe on Filter Board P1 pin 6 while adjusting the
Premix filters and simply adjust for maximum RF voltage on the 'scope. If
you have the 4 band board, follow the band adjustment order - 30 meters
before 40 and 15 (17) meters before 20 meters. If you have adjusted the
trimmers for a peak on receive, you should not have to move the setting very
far.
Once you have the Premix Bandpass filters set, then do the RF Bandpass in
the same manner - put the 'scope probe on P2 pin 8 and adjust for maximum RF
voltage.
After adjusting the filters for maximum RF voltage, you can try other
things, trusting that the filter board is adjusted properly. Actually there
is little more to be adjusted that will change the power output. You may
need a bit of 'finger training' to enter TUNE without changing the power
output level. Once in TUNE, you can tap one button to raise the power and
the other to lower it.
I cannot say where the extra voltage at J1 pin 1 is originating at the
moment - it may be coming from the output of U9 - check U9 pin 6 to see how
the voltage there compares with the voltage at J7 pin 1.
73,
Don W3FPR
> -----Original Message-----
> ...
> Sadly, the transmitter has not been so kind. Any attempt to put the
> unit in transmit mode (by pushing WPM+ and WPM- together) resets the
> power out to 0.1 watts, which is confirmed by the external wattmeter.
>
> All of the resistance checks on p45 have passed with the KFL1-4 removed
> and the jumper set to K1 (not KAT1). With the KFL1-4 in place and
> 14.38V at the input jack, a few of the voltage test points on p46
> indicate 0.1-0.2V above the quoted range, which is presumably a result
> of the input voltage being a little higher than recommended. (I can
> stick a diode in the power cord if this is a real problem.)
>
> However, J7 pin 1 shows 7.8V instead of the quoted range of 5.1-6.7V.
> What, if anything, does this indicate? R9, D14, and D5 are all
> connected as measured by the ohm-meter.
>
> I've looked at the schematic, and I don't understand the RF-out path
> well enough to see what the obvious culprits might be. I have the RF
> probe that I built with the K2 plus a Tek scope. Any suggestions before
> I dive into the transmitter signal tracing on page 6 of Appendix E?
>
> A few pointers would be helpful before I disappear into the deep water!
>
> Cathy
> N5WVR
>
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