I've seen the thread about hot versus not so hot soldering irons and will
relate my experience in specific terms:
I use Weller soldering irons, they are blue and the tip can be replaced.
I've used the 40 watt irons with a 'screwdriver tip' about 1/8 inch across.
They were too hot for circuit board work (for me) but worked well on bigger
solder lugs with big wires attached.
I prefer the 25 watt model Weller with a screwdriver tip 1/16 inch or
slightly smaller for circuit board work.
These Weller things may be long gone from the market place, but watts is
watts.
NOTE: Your mileage may vary.
73 and good luck,
Mike Hyder -N4NT-
----- Original Message -----
From: "Paul Harker" <paul.r.harker@gmail.com>
To: <tentec@contesting.com>
Sent: Monday, October 14, 2013 17:28
Subject: [TenTec] Omni C + new Ham = Oops.
I am a new member of the amateur radio community, and my first HF rig is an
Omni C. I was attempting to tune an antenna with a MFJ949E, with the mode
select switch (SSB-R / SSB-N / CW / LOCK) switch in the LOCK position, and
DRIVE set just high enough to allow tuning.
Suddenly the antenna tuner needles dropped to zero, and it appears I no
longer have RF output. The Model 255 power supply did not shut down, and
the receiver is still functioning. I am assuming that I managed to blow
the
MRF458 output transistors due to doing _something_ wrong. Maybe just a
matter of fiddling too long and letting things get too hot. I don't know.
Measuring the MRF458 with a meter suggests they might be bad, but it isn't
a case of a dead short, and in the past I've found that power transistors
can be deceiving when doing an in-circuit test.
So... I looked for any sign of a fusible link or other protective circuit
in the Omni schematics and didn't see any, but I thought I'd ask the
experts before pressing "sumbit" on a transistor order.
And any hints tips corrections to keep me from repeating my bungle would
also be appreciated.
Much thanks,
Paul
AC8OI
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