[Collins] 75S-1 CW non op question

[Dr. Gerald N. Johnson]

Without the CW filter ever having been installed, there is also no 
crystal for the BFO in the CW mode so the product detector has a huge 
signal loss. The only gain working to the speaker is in the two audio 
stages, the detector is one signal break and the lack of filter is a 
second signal break.

73, Jerry, K0CQ, Technical Adviser to the Collins Radio Association.

On 9/30/2016 12:25 PM, Rodger Singley wrote:
>
>
> Chris,
>
> Nothing is wrong with your 75S-1, it MUST have the CW filter installed
> to work with the emission switch in the CW position. Without the filter
> use either the USB or LSB position to receive CW.
>
> Many receivers are configured this way where a certain mode setting will
> not work without the required accessory filter also installed.
>
> Rodger WQ9E
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
> *From: *Chris Kepus <mailto:ckepus at comcast.net>
> *Sent: *Friday, September 30, 2016 12:06 PM
> *To: *geraldj at netins.net <mailto:geraldj at netins.net>;
> collins at mailman.qth.net <mailto:collins at mailman.qth.net>
> *Subject: *[Collins] 75S-1 CW non op question
>
> Hi all,
>
> I am in the process of bringing a 75S-1 back to life. At the moment, it is
> playing USB/LSB and AM nicely. But....No CW. Note: It does not have a
> CW filter installed and appears not to have ever had one installed.
>
> When I turn the Emission switch to CW, the radio goes "dead". Power stays
> on but that's the only indicator that there's power to the radio.
>
> I've studied the manual and am now going to trace out the circuitry switched
> in/out with the Emissions switch.
>
> Sure would appreciate any tips that would expedite my trouble shooting
> efforts.
>
> 73,
>
> Chris
> W7JPG
>
>
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