Re: [TenTec] Omni C + new Ham = Oops.

["Mike Hyder -N4NT-" <Mike_N4NT@charter.net>]

My Wellers are the models WP-40 and WP-25. My 'screwdriver tip' on the WP-25 
is probably 1/32 across the rounded tip.
Mike -N4NT-

----- Original Message ----- 
From: "Mike Hyder -N4NT-" <Mike_N4NT@charter.net>
To: <tentec@contesting.com>; <paul.r.harker@gmail.com>
Sent: Friday, October 18, 2013 18:31
Subject: Re: [TenTec] Omni C + new Ham = Oops.


> 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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