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

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] Omni C + new Ham = Oops.
From: "Frank A. Ellis" <w3uhf@yahoo.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Fri, 18 Oct 2013 19:14:12 -0400
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
In addition to my Metcal soldering station I have an old blue Weller 40W iron 
on a small variac at my repair bench. The variac makes the iron very flexible, 
and tips can be changed in seconds. I'm getting to where I use the iron/variac 
combo even more than the much more expensive soldering station.

73 Frank W3UHF




On Oct 18, 2013, at 6:31 PM, Mike Hyder -N4NT- wrote:

> 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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>> TenTec@contesting.com
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> 
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