*Jon,*
* The first thing that I would do is replace PIN Diodes D-1 thru D-8
.... These diodes were a very common problem " Back in the Day " You could
also measure the forward voltage drop on these diodes and see if one of
them is leaky or shorted but, I would just change them all. That is what we
do here. They are responsible for the Transmit/Receive Switching. I sure
hope that we have helped.*
* 73 from
Wade/KJ4WS*
On Mon, Oct 5, 2015 at 9:40 PM, jon greenwood via TenTec <
tentec@contesting.com> wrote:
> Hope some of the good troubleshooters on here can point me in a direction.
> I have a Corsair 2 that is very weak on receive. I have checked transistor
> voltages on IF/AF board 80984, the Osc/mixer board 80975, and the RX mixer
> board 80987. All seem good or very close to specs in manual, except Q6 on
> RX mixer 80987.
> I am reading 11.5 volts on base emitter and collector in receive mode. In
> Transmit these all read correctly base emitter and collector zero volts. I
> replaced the 270pf cap C24 as well as C25 5-25pf variable cap. No change. I
> removed the Q6 transistor and the radio receives exactly the same. I
> replaced with a new transistor with no change. So my thought is a bad a
> component around Q6 but at this point I am stumped on what it is. I also
> checked D7 and D8 pulling them off the board and just checking with my ohm
> meter. Flow in only one direction on each so they seem good.
> Any thoughts/ test procedures would be much appreciated. I have a 100mhz
> digital scope and an older Fluke DMM that I have to work with.
> Questions/Thoughts? Jon N8MUS
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--
*Living one day at a time with Jesus as my Savior. But, still having Fun.*
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