Re: No output QCX 40 output drains show 1.6 watts in receive


George Korper
 

Hi Alan,
Game over as I don't have a replacement for IC3.
I did order another 40 QCX and i will take all the experience
and now with skills at voltage checking, do better next time.
Again thanks and best 73's
George

On Wed, Dec 11, 2019 at 2:53 PM Alan G4ZFQ <alan4alan@...> wrote:
> CLK 1
>     goes from 1.7 on receive to zero on transmit.

George,

That's enough to tell it is going to TX mode.
You need to remove IC3 and test the voltages on it's pin 4 and pin 12
pads, RX and TX modes.

IC3 can be removed by carefully cutting each leg then removing each leg
separately.

73 Alan G4ZFQ
>
>         IC3 looks as if it has failed. If pins 1,2 are high then pin 1
>         should be
>         low.
>         What are the voltages on Q1,2,3?
>
>         Also it looks as if IC1 is not sending a TX signal to IC3 and
>         that Clk2
>         is not turned on for TX.
>         Is it going into TX mode? Does IC1 pin 3 go low when the "Key"
>         switch is
>         pressed?
>
>         



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