Re SB 102

[Glen Zook]

When the meter is in the plate function, the meter
shunt is provided by several 10 ohm resistors in
parallel off of the 6146 cathodes.  This is true in
the SB-400, SB-401, SB-110, SB-110A, as well as the
SB-100, SB-101, SB-102, HW-100, and HW-101.  Often
these resistors have changed value (sometimes going
high and sometimes going low).  This will cause the
meter to read improperly.  If they have gone low in
value, then the meter will read less current than is
actually going through the finals.  If they have gone
high in value, then the meter will read more current
than is actually going through the finals.

The "fix" is to replace all of these 10 ohm 1/2 watt
resistors with new 1 watt carbon film resistors.  The
new 1 watt resistors are about the same physical size
as the original 1/2 watt resistors.  Use those
resistors with 5% tolerance.

I had to do this with both my SB-110A and SB-401 when
the meter readings didn't agree with the power output
readings from my Bird wattmeter.  Of course, the input
power is more than the output.  However, the
relationship of input to output was known and the
readings just didn't "jive".

Glen, K9STH


--- "Bob, WB2UJD" <BobbyTrip at AOL.COM> wrote:

As for the S-meter, I don't know much about it's
function in xmit, but problems with the meter in the S
meter position are almost always related to R107
(100K) drifting high.  R106 may be a problem as well

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