HF PackerAmp V4, Construction Manual

Page: 40 / 76

HF PACKER
AMP
V4R6 Page 40
violently up in flames when grounding pin 2, the fly back
sensor to control output voltage. The voltage divider R13 and
R16 is used to tell the sensor the output voltage. The LT1270A
will try to increase voltage on pin 4 until voltage on pin 2 from
the voltage divider reaches 1.24V. This can result in
dangerously high voltages on pin 4, when pin 2 is mistakenly
grounded. Also note, that the middle pin 3 is at ground while
pin 4 carries output voltage of about 30V.
Those two pins can be easily shortened when probing. Better,
measure input voltage (pin 5) at the cathode of D5, measure
output voltage (pin 4) at the anode of D4, measure fly back
voltage (pin 2) at R13, and measure the control state (pin 1) at
R14 (converter off when at ground). Be very careful!"
RF Power Testing
•
Attach 12VDC power source capable of supplying 10A
continuous current. The 12VDC source should be
fused at 20A.
•
Monitor Current
•
Connect XCVR set for 160M and 5W setting
•
Set Band Switch for 160M.
•
In BYPASS mode, adjust the power out to 5W ______
•
In ONLINE mode and key down for a few seconds,
observe the power output and DC current.
•
Record your power output and DC current for each
band in the Frequency vs Watts vs Amps Table.
•
Plot your Power Out and Amps results vs Frequency.

If you see an unusual spike up in DC current or drop
in power, your LP filter may be suspect.
FREQ MHZ WATTS AMPS
1.9 45 7.5
3.9 40 7
7.3 35 7
10 35 8.3
14.3 35 7.3
18.7 29 8.2
21.3 30 6.7
24.9 25 5.5
28.4 20 4.5
Frequency vs Watts vs Amps Table
Frequency vs Watts vs Amps Plot

Power Input Constant at 5W set for each band
0
10
20
30
40
50
0 10 20 30
WATTS
AMPS
WATTS
AMPS