[ICOM] IC761 problem

[Alan]

Hi Gary,
Well I have run my Grid Dip Oscillator across the band(20 metres) which 
it is switched to at the moment and can not pick up a signal from the 
GDO. The noise increases when I hook a wire to the antenna terminal 
which suggests the RF stage is partly working and also turning the 
preamp off and on changes the noise level, and the RF gain control also 
controls the noise and the meter.
I believe that I am picking up a signal from the gdo around 70Mhz (my 
gdo is homebrew and not calibrated up there)but it is untuneable making 
me think that the ocillator to the first Mixer is not operating, and 
according to the book that is coming from a PLL circuit, so I wanted to 
be sure that the same PLL wasnt also involved with driving the digital 
frequency read out which is functioning correctly
Alan ZL3KR




On 20/05/2010 00:13, Gary P. Fiber wrote:
> Alan,
>
> What are the problem symptoms? No Transmit or receive at all? Dead spots
> when you tune through the bands?
>
> The display is a readout no oscillator from the display helps operate
> the PLL for the IC-761.
>
> On 5/18/2010 9:47 PM, Alan wrote:
>    
>> My IC761 sounds like it is running without frequency control (like a PLL
>> oscillator is not running)
>> but the digital read out is working perfectly where it tunes and
>> switches bands without a problem.
>> Does the PLL oscillator that produces the 70Mhz signal for the 1st Mixer
>> also in use for the digital frequency display or are they seperate?? I
>> am trying to get some idea of where maybe I should start to look for the
>> problem.
>> Any advice appreciated
>> thanks   Alan Z:L3KR
>>
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>>      
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
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