HF PackerAmp V4, Construction Manual

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TX - Transmit
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On/Standby – TX Enable
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LPF – Low Pass Filter
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XCVR - Transceiver
The IPS signal passes the PSU voltage to the
MOSFETs through the IPS electronic switch U5. The PSU
signal activates the DC-DC converter on from a standby state.
The IPS device acts as a power switch and a over-current
sensor to protect the DC-DC converter IC, U4. The U5 device
purposely heats up rapidly to provide a thermal time constant
circuit breaker if the current exceeds 5A. After the U5 device
cools, the circuit breaker automatically resets.
A TEST jack, H3, provides a means to set the bias
current. A jumper is provided to activate during calibration. CW
and SSB post delay time is an automatic function. If the amp
senses you are operating SSB, the post delay time is
optimized for SSB. Revert to CW mode by cycling power. A
front panel switch through J5 sets the AMP for ON/STANDBY.
In STANDBY, the transceiver signals are routed directly to the
antenna jack via J4.
Preparation
You may have purchased a fabricated cable set or the
fabricated coil set. Skip over the sections that don’t apply. The
most important preparation step before building is to
completely and thoroughly read this section of the manual.
This will familiarize you with the circuitry, building requirements
and components.
After reading this document and prior to assembly you
should do an inventory of parts (Appendix A-C). In the unlikely
event that you appear to have missing parts, duplicates or
wrong parts please first double check for the parts in all bags,
recheck the inventory and if this fails please contact the project
organizers. This might also be the time to re-acquaint yourself
with how to identify resistors and capacitors by the standard
coding (Appendix E), if you have forgotten.
Construction Techniques
It is a fact that 90-95% of problems with completed
electronics/radio kits are due to either component
misplacement or soldering faults. We cannot stress highly
enough the importance of double checking component
installation before soldering and then good soldering technique
in order to have a working amplifier at the end of this project.
Other builder faults are active component damage due to over-
heating and damage to circuit board pads and tracks caused
by poor de-soldering, too high a wattage of soldering iron or
carelessness. It is very rare to have initially faulty components
or printed circuit boards (PCBs).
Good Soldering Technique

use a 12-25 watt soldering iron with a clean, non-
corroded, well-tinned, fine tip

keep the tip clean by frequently rubbing it along a wet
sponge

keep the tip tinned