[TenTec] Replacement Titan 425 Relay

[Dave Bowker]

Several have asked if a replacement relay is feasible.  I have successfully
swapped out the original 12 VDC K41C relay with a 26.5 VDC HC-1 relay ($35
in surplus circles) and have run it extensively in long contests and almost
nightly at full power on all bands thru 28 MHz with a matched load.  If you
look at the photos in the manuals accompanying some of the older Titan 425's
you will see a relay that looks remarkably like the HC-1, rather than the
K41C, even though a K41C is installed in the amplifier!

The HC-1 slips into the same grommet as the K41C, but requires removal of
the 68-Ohm/2W series resistor on the relay board.  The HC-1 is far quieter
than the K41C and has a bit faster operate time, but a slightly lower
contact rating  than the K41C.  I can provide modification instructions,
specifications on both relays,  and JPEG photos of my installation via email
to anyone interested.  This modification should apply to any Ten-Tec amp
which uses the K41C relay.

As a side note, I did some investigation into the specifications of the K41C
relay versus the HC-1, and in my humble opinion, the K41C is being used in
an application for which it was NOT intended by the manufacturer.  The
manufacturer's specifications rate this relay as a "MAKE AND BREAK LOAD
SWITCHING" relay, which means that it must see some current flowing through
the contacts on make and break to keep them properly conditioned (cleaned).
This is not the case in the Titan 425, because the interlocks with the
transceiver (OMNI-VI+ in my case) prevents hot switching.  The HC-1 is rated
as a "NO LOAD SWITCHING" relay, which means that the contacts are
specifically designed to switch loads which have no current flowing on make
and break and still maintain the contacts conditioned (cleaned).

73, Dave, K1FK
Fort Kent, ME

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