[TenTec] Corsair II, PTO output level

[Thomas Kuehl]

Hi Jerry,
 
The Corsair II fold-out shows the PTO output routed to the 80975 Oscillator-Mixer board. The signal splits at that point going to U1, the TL442 mixer IC, for all bands except 20 meters, and then to a 270 ohm/150 ohm divider for 20 meters. That divider consisting of 420 ohms total resistance and is likely the majority loading for the PTO output. I do think all of the other impedances seen by its output are much higher.
 
Interestingly my mixer IC is not the rare TL442, but instead an MC1496. I heard long ago that the TL442 had a limited production time and Ten Tec scrambled to retrofit the MC1496 into the mixer role. It is still very available today, while the TL442 is past history. My mixer board doesn't have any of the silkscreened component numbers, or outlines. 
 
'73, Thomas - ac7a
 

________________________________
 From: Jerry Haigwood <jerry at w5jh.net>
To: Discussion of Ten-Tec Equipment <tentec at contesting.com> 
Sent: Monday, March 24, 2014 7:11 PM
Subject: Re: [TenTec] Corsair II, PTO output level
  

Hi Steve,
    What was the load impedance?
Jerry W5JH
"building something without experimenting is just solder practice"

----- Original Message ----- 
From: "Steve Hunt" <steve at karinya.net>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Monday, March 24, 2014 3:34 PM
Subject: Re: [TenTec] Corsair II, PTO output level


> All four of mine measure close to 1.2v p/p
>
> Steve G3TXQ
>
>
>
> On 24/03/2014 20:06, Thomas Kuehl wrote:
>> Hi,
>>   Does anyone know what the correct peak-to-peak output level is for a 
>> properly working Corsair II PTO?
>>   Any assistance is appreciated.
>>   '73, Thomas - ac7a
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>>
>
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