Funny thing about all that..
Several years ago I noticed on my O-565 that the white housing surrounding the
+ pin in the Molex-style cable connector had turned brown from the heat over
the years, which was odd since I operate mostly cw and never any RTTY or other
high duty cycle modes. So I replaced it with power poles according to the
procedure outlined by several folks and it worked fine. Later I had a need to
send the radio in for repair for an unrelated problem and when I got it back,
my power pole mod had been un-done and returned to the original configuration
with a new white Molex connector. The reason given was that they couldn't
warrant any work done on a "modified" radio.
Not wanting to repeat the un-soldering process again, I left it alone and went
back to the original connector design (new connector on the cable). Now after a
few years of very little use, I notice the same discoloration on the + pin
again. So now I'm in the process of repeating the mod again back to power poles
on a pigtail (I don't like rigid "things" mounted to a PC board protruding thru
a cabinet).
I'm not sure I understand yet why its just the + lead that's having the heat
problem, but it won't anymore! It made me wonder if some of the DC current was
finding another path back to the power supply besides the power connector, but
that's highly unlikely.
73, Art N4UC
________________________________
From: TenTec <tentec-bounces@contesting.com> on behalf of Ben Antanaitis -
WB2RHM <wb2rhm@wb2rhm.com>
Sent: Saturday, November 5, 2016 11:36 AM
To: tentec@contesting.com
Subject: [TenTec] Power Connectors
FYI-
From a 2009 posting to another group:
>>>>>>>While I love the performance of my Orion............
The thing that disturbs me the most about the DC
connector problem, (and before I looked into it,
I had replaced the 'stock' parts 4 times), is
that for years Ten Tec advertised "100% Key Down
operation" when the optional fan unit was
purchased and attached to the heat sink on the
rear of the 565 and they supplied a DC power
cable (and a replacement connector and pins).
Well, if you read the specs for the 565 you will see:
"The ORION transceiver requires a source of
well-filtered and regulated DC voltage. The
supply voltage can range from +12.8 to
+15.0 Vdc but +13.8 Vdc is the optimum
value. The voltage source must be capable
of supplying 22 amperes continuous duty.
We recommend using the included DC
power cable (P/N 86095). We have also
included spare connector pins (P/N 41020)
and a spare 2 pin power connector shell
(P/N 35165) (Tyco/AMP Mate-and-Lock) for building your own cable.
The power supply plug will attach in only
one direction to the polarized two-pin DC
connector on ORION's rear panel. Use no
less than #14 gauge (#12 recommended)
stranded wires for three-foot long <-- note 3 foot cable
connections to accommodate the required
current demand during transmit. Use
heavier gauge wire for longer power supply
leads."
BUT, if you read the Tyco/AMP Mate-and-Lock specs
for the socket, plug, and pins...... (Tyco
documents 108-1031 and 114-1010 and 108–1053).
You will see a 15 amps max current capacity for
normal product use on the socket and the plug,
and 20 amps as the product absolute limit for the
221 degrees temperature for the plug housing.
Note that that 20 amps max is only 90% of the Ten
Tec specified Power Supply minimum constant DC
current requirement. No safety factor margin here.
Is this sloppy engineering, bad engineering, or cost of part engineering?
Now, for example, if you are a high duty cycle
mode operator, and I am a RTTY contester and RTTY
is almost 100% duty cycle under contest
conditions.... the pins overheat and then the
housing overheats and that leads to total
connector failure over time.......... smelling, smoking, burning, oh my!
I have been told that the connector, pins, and
socket are specified correctly...... I just don't think so!
I have removed them all and run #14 wire directly
from Power pole connectors to the PC board.
Haven't had a problem since. <<<<<<<<
2016, still running same 30AMP Power Poles and
#14 gauge wire with no problems on the power
source side. (Had to do the A9 total replacement, but that is another topic)
73,
Ben WB2RHM
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