HF PackerAmp V4, Construction Manual

Page: 38 / 76

HF PACKER
AMP
V4R6 Page 38
•
Connect for Current Measurement on the 10A scale.
•
Online/Bypass Switch placed in Bypass position.
•
Connect to a DC 12V source and Power Up. The
current is less than 30mA.

If the Meter reading is negative, reverse the meter leads.
If your meter does not have high resolution, you may have to
use a smaller scale to measure mA.
There can be a current
surge when power is first applied that can blow the low
current fuse in your meter
. Use a jumper across the meter
during turn on to shunt the current around the meter. Remove
the jumper after a second or two.
•
LED should be OFF. Record: _______mA
•
Use small screw driver to short TEST pins. The LED
should light.
•
Current is about 85 mA while the pins are shorted
together and the LED is on. Record: _______mA .
RF Signal Testing
•
Switch the Online/Bypass Switch to ON. Key the
XCVR. The LED lights. (1W RF drive)
o
If Fan option, fan is ON. Current = 0.25A.
o
Else, Current = 90mA
•
Release XCVR KEY. The LED is OFF and the FAN
turns off after the hold time expires.
•
Measure from case ground to the right side of R18.
Key the XCVR. The voltage switches from 0.0VDC to
about 29.5VDC.
•
H4 no longer has function. CW/ SSB selection is now
automatic. See description in section six.
•
Tap the key on XCVR. Note the time that the LED is
ON and that the fan runs.
•
Tap the key on XCVR. Note a longer LED ON time and
fan runs.
•
Rig a toggle switch and RCA plug to test the PTT
function. Plug into the RCA Jack.
•
Close the PTT test switch. The LED lights and the fan
runs.
•
Open the PTT test switch. The LED is off and fan stops
running.
DC Current Test and Bias Adjustment
•
Insert the jumper plug over the TEST pins of H3.
•
Start with either potentiometer and turn clockwise while
measuring current. You may have to turn the pot screw
about 15 turns CW before the current starts to climb. It
will climb sharply when the MOSFET begins to
conduct. Adjust the current to increase the current by
100mA. New current reading: _______mA.
•
Turn the other potentiometer clockwise to increase the
current by an additional 100 mA. New current reading:
________mA.
•
Remove the jumper plug from H3.
Voltage Test
•
It is handy to have a second multi-meter to make a
voltage measurement s while monitoring current. If a