Hi, Greg,
Lacking a schematic for the Pegasus, I wonder if it wouldn't be prudent to
discuss the grounding of the pin 2 with Ten-Tec first. From previous posts, my
understanding is that the speaker audio output jack ground is floating also.
There may be some problems generated as a result of grounding pin 2 to chassis.
73,
dale, kg5u
-----Original Message-----
From: Greg Hodsdon <k7kj@teleport.com>
To: Dale L. Martin <kg5u@hal-pc.org>
Cc: tentec@contesting.com <tentec@contesting.com>
To: <tentec@contesting.com>
Date: Thursday, December 09, 1999 18:59 PM
Subject: Re: [TenTec] RF & Pegasus
>After noting that my modified D-104 mic stand (with a preamp from recent QST
>article) with PTT bar would not key the Pegasus but does fine with the Omni 6
plus,
>I started wire checking the circuit. The Pegasus measures 4.99vdc across pins
2
>and 4 on the mic jack using a Fluke dvm. The other interesting item is that
the mic
>jack (threaded section on the panel) is not grounded and, in fact, is
floating.
>This is not the situation on the Omni 6 plus, where pin 2 is grounded and the
mic
>jack is grounded by virtue of its being mounted to the aluminum chassis. Also,
my
>recollection is that the voltage on pin 4 on the Omni is well over 8vdc. I
called
>TenTec on this issue and all was confirmed. My plan is to tie the Pegasus mic
jack
>to ground and raise the voltage on pin 4.
>
>An interesting thought: With the mic jack ungrounded, this means the mic cable
>shield could be floating, depending upon how the connector is wired. Could
this
>possibly be a reason for some people experiencing RF in the audio with some
>microphones?
>
>Using the 705, I am getting good audio reports from the Pegasus.
>
>73 de Greg, K7KJ
>Portland, OR
>
>Dale L. Martin wrote:
>
>> My 705 schematic shows pin 4 and the + terminal of the battery each feeding
>> through respective steering diodes (1n4148), then directly to pin 14 of the
>> 14013 (a CMOS Dual D type Flip-Flop). CMOS typically works across 3 to 15
>> volts. After the .7 volt hit through the steering diode, any 4.5v source
would
>> be very close to the hairy edge. I'm betting it's better than 4.5 volts
across
>> pins 2 and 4 of the Pegasus mic jack--more along the lines of 9+
volts....the
>> Omni VI derives it through a 470 ohm resistor from +REG (13.8v?).
>>
>> Someone, please, measure the Pegasus pin 2/pin4 voltage. Settle this issue.
>>
>> 73,
>> dale, kg5u
>>
>> -----Original Message-----
>> From: JEFF S JOHNSON <aa8ve@juno.com>
>> To: tentec@contesting.com <tentec@contesting.com>
To: <tentec@contesting.com>
>> Date: Thursday, December 09, 1999 15:35 PM
>> Subject: Re: [TenTec] RF & Pegasus
>>
>> >
>> >I checked my Omni-V and the output for the mic is 8.6 volts. I wonder
>> >why they now supply only 4.5 volts? Is anyone running a 705 off the
>> >Pegasus with any problems? Perhaps 4.5 is enough to run the 705 from
>> >anyway. What is the voltage out in the mic jack on an Omni-VI anyway?
>> >
>> >73 Jeff aa8ve
>> >
>> >On Thu, 9 Dec 1999 13:22:19 -0400 (AST) David McClafferty
>> ><at060@chebucto.ns.ca> writes:
>> >>
>> >>
>> >>
>> >> On Thu, 9 Dec 1999, JEFF S JOHNSON wrote:
>> >>
>> >> >
>> >> > I should hope Pegasus has DC voltage out for the Mic. so a battery
>> >> is not
>> >> > needed.
>> >> >
>> >>
>> >> I did not have a battery in my 705 when I used it with the Omni V.
>> >> When I
>> >> got the Pegasus the LED on the 705 base would only glow very dimly
>> >> and
>> >> the rig was obviously not being fully modulated, so I had to put a
>> >> battery
>> >> in. The manual says it provides 4.5 Volts for electret mics.
>> >> Appearently
>> >> that not enough for the 705. I hope that we will get schematics
>> >> someday so
>> >> one could look into modifying such things. I hate batteries, they
>> >> leak and
>> >> ruin a lot of good gear.
>> >>
>> >> 73, Dave, VE1ADH
>> >
>> >
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>> >
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>
>
>
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