Posted by
David Woolley (E.L) on
May 28, 2007; 12:00pm
URL: http://elecraft.85.s1.nabble.com/K2-8A-Control-Resistance-2-72-to-3-50-depending-on-R1-tp448215.html
Hi,
I've assembled the control board (and most of the front panel. In
doing the control board resistance checks I've got an apparently out of
range value for the 8A value. With R1 at the low resistance end of the
track, it is 2k72, which is below the minimum of 3k0, in the manual.
With R1 at the high resistance limit, it is 3k5. Do I have a problem?
In particular, does the spread given in the manual account for the R1
settings (I would have declared a pass if R1 had been set high enough
initially).
I've checked lots of things without finding a problem. The resistance
is not obviously polarity sensitive, although it shows a slight positive
dependency on the temperature of the 8V regulator (50R when it was
warmed with an iron set to 75 deg C), so some of it is leakage through
the regulator.
The resistances from the bases of Q1 and Q2 are the approximate 3k9
higher that you would expect if both FET's were cut off.
Do I have anything to worrry about, or should I wait to the first stage
test?
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