I think if you could go back and check, you would find the serial number of
your IC-781 was less than #1300. Prior to #1300 the 781's had a very poor power
supply design and when you ran full 150 watts out, the power supply pass
transistors could not dissapate the heat that was being generated in the power
supply and would subsequently shut the rig down until it cooled off.
I now own one whose s/n is in the 2300's and that problem is no longer present.
I run my 781 at speeds in excess of 60 wpm, at 140 watts output, and with full
QSK. And there is no problem!
As with any solid state radio, you can always help yourself and your radio by
adding a small outboard 12vdc fan directed on the rig's heatsink. I do that for
both my Omni 6+ and my IC-781. A semiconductors greatest enemy is HEAT!
At 08:26 AM 8/28/97 -0700, you wrote:
>You guys want to hear horror stories about the Yaecomwoods?
>
>I once used one of the Coast Guard's IC-781 on field day back in 1993. I was
>QSK CW running 20 meters on a VERY hot streak when the radio suddenly shut
>off! Aparently it will not take CW duty cycle on full (150 watts) output!!
>We had to wait for it to cool off with ice packs and cold sodas until the
>finals would come down in temperature to let me turn it back on again.
>
>That's why there are no CW radios in my opinion that don't use tubes in the
>P.A. Stage. They may not be QSK, but they can take the heat and come back
>smiling.
>
>The TS-520 is a good example of this.
>
>Have fun and GL,
>
>Adam
>
>
>Adam McLaughlin KD6POC
>QRG: 7037 Kcs & 7014 Kcs (DX Only)
>kd6poc@jps.net
>www.jps.net/jmclaugh
>
><< >
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Chester Alderman
<color><param>0000,0000,ffff</param>W4BQF -- Tom
</color><color><param>ffff,0000,0000</param>chestert@pressroom.com
</color>
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