HF PACKER
AMP
V4R6
Page 43
Do’s and Don’ts for Successful Operation
•
Do set the band switch to match the XCVR band
•
Do not exceed 5W drive
•
Do tune the antenna only in the BYPASS position
•
Do not touch up antenna tuning in the ON position
•
Do not operate with an SWR > 2.0:1
Maintenance Issues
•
If your power drops to near zero or the TX LED does
not light during transmit or you hear a squealing noise
from the amp, you have probably blown a MOSFET
Warning, the surface mount chip, U5, can be hot to the
touch if you short a MOSFET. The hot U5 chip purposely gets
hot acting as a thermal controlled circuit breaker for the DC
power to the MOSFETs.
•
Replace both MOSFETs: Always replace both. Spares
are available from Radio Shack or HF Projects.
•
Remove the four top screws and two MOSFET Socket
Cap screws to allow the circuit board to be removed.
Also disconnect the two flag terminals for the 12VDC
input.
•
Unplug the cables to the board. Remove the circuit
board from the case.
•
Clip out the MOSFETs and remove the pins remaining
in the board. Tweezers and soldering iron works.
•
Remove excess solder. Clean up flux.
The most important issue is to save the board circuit
connections by carefully removing the old pins.
•
Follow the installation procedure outlined in Section
Four
•
Re-install MOSFETs using the non metallic 6-32 x 5/16
cap head screws.
CW/SSB Auto Selection
The amp has auto switching between CW and SSB hang
time delay.
CW hang time is 0.15 seconds while the SSB hang time
is 0.50 seconds.
The amp powers up in the CW mode. To switch to SSB
mode, key the amp for greater than 2.5 seconds. It
will remain locked in the SSB mode until you cycle
power.
Normal CW keying will typically not exceed a
continuous carrier of greater than 2.5 seconds.
Normal SSB use will exceed 2.5 seconds of carrier in
normal conversation at some point.
If you hear the relay chattering between syllables it
is still in the CW mode. No harm done because the amp
switches on and off without missing a beat. To
activate into SSB make one continuous sound (such as
Helllllloooo
) and it is now locked to SSB.
In CW, you will have to be aware that holding the key
down > 2.5 seconds will switch the mode to SSB.
The H4 posts on the amp where you could put a jumper
is no longer assigned any function.
If you are using PTT, CW/SSB selection is not active and
timing is solely dependent upon the PTT signal.
Summary of Contents for PackerAmp V4
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