Re: {Collins} 75A2 opereration



Sometime ago, The ham club was donated from a SK's Estate an older xcvr (not
Collins). It transmitted fine, but the rcvr was so weak that you could put a
signal into it and put your ear up to the speaker with af and rf gains wide
open and hear it faintly in the background and tune across it, just as John
described. We tried checking the tubes (all within range) and voltages (all
ok) and cleaned and exercised all the variable controls and switches but it
just wouldn't come around. We were ready to give up and feed it to the
dumpster and one of the guys took it home, put in his shack, and turned it
on with the af gain down and left it (we had already determined that it
probably wasn't going to explode). He came back several days later and it
worked fine, We all puzzled over that result and no one has yet figured it
out. The only times it had been on for up to 15 years was the few Saturday
mornings when many of us get together at the clubhouse. The theories
centered the reforming of something, a coupling condenser perhaps. While all
the advice you have gotten so far is excellent and probably, in the end,
will yield you the result you desire, I would suggest that you also leave it
on (again assuming that your are not concerned about it catching fire or
some other catastrophe) Can't hurt. Gud luck with the project, the A-lines
are great rcvrs. 73, Bob K9ING

-----Original Message-----
From: Brian J. Henry [mailto:bhenry@xxxxxxxxx] 
Sent: Sunday, July 17, 2011 10:22 AM
To: John King; Collins@xxxxxxxxxxxxx
Subject: Re: {Collins} 75A2 opereration

John,

I don't know if this will help, but when I first acquired my 75A-3, I found
the small wires that connected the RF input to the input of the 80m-10m
input transformer had burned up due to the application of high level RF to
the receiver RF input.

Brian Henry, WB6QED

> -----Original Message-----
> From: John King [mailto:k5pgw@xxxxxxxxx]
> Sent: Sunday, July 17, 2011 7:24 AM
> To: Collins@xxxxxxxxxxxxx
> Subject: {Collins} 75A2 opereration
>
>
> Thanks to Charlie, Darryl,Ted, and Steven for their email and suggestions.
>
> Since my first post, I have hooked a signal source (antenna
> analyzer) to the coax connector on the 75A2 and have gotten a
> faint signal through the receiver from the antenna analyzer. Not
> enough signal to move the S meter, just audible as noise.
>
> The PTO seems to be working because I can tune across the signal
> from the analyzer. All controls have an effect on the noise
> coming from the speaker. The BFO doesn't impress me as working.
>
> Still looking. Thanks and 73, John, K5PGW
> _______________________________________________
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_______________________________________________
SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
http://www.collinsradio.org/membership/

 NETS: Tues & Thur: 3.805 MHz-2000 Central + Fri: 3.895 MHz-2000 Pacific
  SUNDAYS: 14.263 MHz-2000 UTC  +  AM Net: 29.050 MHz-1200 Central
  1st Wednesday AM Net 3.880 MHz-2000 local (ET, CT, MT, PT)

The Collins Reflector reserves the right to refuse access to anyone.

LIST HELP?  ADMIN EMAIL:  collins-owner@xxxxxxxxxxxxx
This ONLY goes to the list admins and does not post to the group!








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