[Elecraft] KSB2 problem status: befuddled

[W3FPR - Don Wilhelm]

Neal,

There may be nothing wrong with 40 meters after all - I had missed the point
that you were setting the Power control to absolute max.  What is your power
supply voltage?  13.8 volts is typical (13.6 on the display), and lower
power supply voltages will result in increased current draw.  What is the
voltage when you are seeing a current of 3 amps or greater?

I don't have a straightforward answer here.  Can it be that your Carrier
Balance is not correctly set and you are really generating more RF drive
with SSB than with CW?

It is not really a fair comparison to compare current draw from band to band
with the Power control set all the way clockwise.  Set it to 10 watts and
check the current drawn for each band and both CW and SSB modes.
Actually SSB mode should draw little current without audio if the carrier is
balanced because there should be little or no RF output.

73,
Don W3FPR

> -----Original Message-----
> Hi Don and all,
>
> I have spent the afternoon looking for where I could have made a
> mistake on the 40m LPF circuit. I didn't find any obvious ones, the
> toroids came from 'The guy de Toroids' but I counted them all anyway,
> and they are (luckily!) correct. Same for capacitors. Did the run of
> voltage checks and didn't notice anything really wrong.
>
> On cw, cranking the output knob to the max, the display readings for
> current are
> 80 3.22
> 40 3.36
> 30 2.84
> 20 2.38
> 17 3.08
> 15 2.84
> 12 2.62
> 10 2.42
>
> Output reads over 15 watts in all cases, usually abt 15.2. This reads
> pretty much the same with or without the SSB module installed.
>
> I take it from your comments that the fact that 40m is the highest cw
> reading, its indicative of something wrong. Looked at LPF and BPF
> areas. What should I expect on the amp readings, 2.35 on 40 and a
> gradual increase as I go towards 10m?
>
> I could reinstall the resistors and jumper and take out the noise
> blanker module as thats something put in yesterday, I take it that I
> need to do that if I want to test without it?
>
> I have boosted cal cur to 4.0 and still can get hi cur signal with
> output fully counterclockwise on both usb and lsb. I have been very
> happy working cw all week as it is (set the cal cur to 3.5 and it
> hasn't tripped yet).
>
> Any more ideas to look at?
>
>
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