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WARNING!
As soon as you plug in the Percolator, there is LINE VOLTAGE across some parts
of the exposed circuit board. Touching the board could shock, injure, or kill you! NEVER
TOUCH ANY PART OF THE CIRCUIT BOARD WHEN THE AMP IS PLUGGED INTO THE WALL!
Before you turn the power switch on, set your multimeter to test AC voltage. Measure the AC
voltage across the IEC power receptacle as shown.
factors, you should measure between 115VAC and 120VAC (or between 220VAC and 240VAC
if you got the international power transformer). The amplifier was designed to use 118VAC from
the wall outlet (230VAC for the international transformer), so the voltages listed in the test
procedure are based on that. If your AC voltage reading is different than 118VAC (or 230VAC),
then the voltage readings in the next few steps will be off proportionally. Theoretically, if the input
voltage from the wall outlet is off by a certain percentage then all of the rest of the voltages in the
amp will be off by the same percentage. The tolerances of the tube and the rest of the components
can easily vary by 5%, so that could cause a bit of voltage fluctuation as well.
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5.
Set your digital multimeter to read DC voltage. In this amp,
all DC voltages are measured with respect to ground, so
the black probe of your multimeter should be held at
ground potential. This amp has several places at ground
potential that are good to put your black probe. Any
of the vias (the tiny holes throughout the PCB) should
work.
Any one of the 3 square pads on the PCB
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under the IEC power receptacle will work.
also use any place on the chassis, assuming the ground lug
is making good contact with the chassis.
on any of those places while making DC voltage measurements.
Depending on several (mostly uncontrollable)
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(a wire with small alligator
clips on both ends) to clip the
negative (black) lead of your
multimeter to the grounded chassis.
That will free up one hand.
You could
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Keep the black probe
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TIP: Use a test lead
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