HERCULES

From: KN4IM@N4CII.#CHS.SC.USA.NA

DC POWER INPUT MODIFICATION TO TEN TEC HERCULES II 12V LINEAR AMPLIFIER

I purchased a new TenTec Hercules II linear for my car.  I run a full
cross-band 600W packet node KN4IM-8 with KN4IM-12/T and KN4IM-10/B on
"Network 105" 14.105 Mhz.  Upon receiving this otherwise outstanding
amplifier, I noticed TenTec cheapened out by putting 100 amps of DC
through a cheap Molex connector that is only popped-in to the back
panel.  I looked up the connector and found it only rated at 15A per
pin.  TenTec uses 4 pins for + (4-#12 housewires are the biggest that
will fit in the pins) and 4 pins for -.  This is not only unsatisfactory,
but is over the limit of the manufacturer of the connector and probably
a fire hazard after the cheap pins corrode (as all Molex connectors do).

I set out to correct this defect in design with a visit to my local
car stereo shop.  These kilowatt "boom box" stereos with their heavy
switching power supplies and big current drains look to be the neatest
thing that will happen to mobile ham radio for some time.  The quality
of the high current parts and nice looking fine-stranded power cables
is outstanding.  I selected 2 "power blocks" for my refit.  The positive
cable, a #4, bright red, fine stranded, very flexible fits just fine
into a dual 50 amp, gold plated fuse block with genuine Stinger gold-
plated fuses.  This Stinger brand fuse block has very heavy allen screws
in the large blocks to clamp down on the wires.  I tinned the #4 wires
before insertion to protect the strands from breakage in clamping.
The negative lead, another fine stranded, #4, black cable goes into
a Stinger brand terminal block that provides 4 connections to this
negative lead.  As there are 4 negative wires to the 4 amp sections
in the Hercules II it is a perfect match with immeasurable resistance.

The amp was disassembled and after looking at the cheap crimp-on push-on
terminals (the kind you would use for audio speaker cables), I decided
there was no use trying to salvage this corrosion prone method of
making assembly fast and easy.  All push-on terminals were cut off the
Molex connector in the back except the wiring used for remote power
control.  As I had no intention of remoting the amp, I made 2 jumpers
in the unused molex plug TenTec provided for the original power cables.
Just copy the jumpers in the power plug they give you to hook amp to
their power supply.
CONTINUED IN HERCULES.1