Re: {Collins} Collins 75A2 receiver operation



OK, we know it's working a little, that's a good thing.
I would take it out of the case and do a very careful visual inspection of 
the wires and components to make sure nothing is burnt or loose, then clean 
all the switches carefully with deoxite and make sure all the screws in the 
chassis are tight. If that doesn't fix the problem I would swap tubes 
starting with V-9, then V-8, then V-7, then, then V-6, then V-5 and then 
V-12.
Good luck,

Steve

J. Steven Cochrane W7JSC


----- Original Message ----- 
From: "John King" <k5pgw@xxxxxxxxx>
To: <collins@xxxxxxxxxxxxx>
Sent: Saturday, July 16, 2011 1:21 PM
Subject: {Collins} Collins 75A2 receiver operation


> Several years ago, I bought a CLEAN Collins 75A2 receiver but did not put 
> it on
> the bench for a check out until today.
>
> Upon plugging it up and connecting a speaker, I get the rush of receiver 
> noise,
> but no signals through it.
>
> There is no Crystal Calibrator crystal in the socket and no nbfm adapter 
> in that
>
> socket. I fired up my HF station, in the house next door to the shop, and 
> could
> receive  no signal on 75 meters or 10 meters from my main station rig.. It 
> acts
> as if something is not hooked up within the receiver.
>
> Yes, I have the switch in the B+ on position and do get receiver noise 
> through a
>
> speaker.
>
> Have I overlooked anything that might be the problem. The S meter moves up 
> and
> down as it should with the change in RF gain control setting. The AF gain
> control varies the receiver noise as it should. When I switch the power 
> switch
> from filament to B+ there is a pop in the audio output.
>
> Any ideas or suggestions as to what might be keeping signals getting from 
> the
> antenna input to the audio stage because of the way i have it hooked up or
> because there might be an overlooked jumper or the rear chassis?
>
> The benefit of Your experience and knowledge of the 75A2 will be greatly
> appreciated. Thanks and 73, John, K5PGW
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