Re: {Collins} 75A-1 deafness



MC HNY be advised TV baluns may have very small ferrite cores and are lossy below maybe 5 MHz , An old one with a fat core is ideal Ted WA8ULG ----- Original Message ----- From: "Bill Carns" <wcarns@xxxxxxxxxxxxx>
To: "'Teran Hermanson'" <twhermanson@xxxxxxxxxxxxxx>
Cc: <COLLINS@xxxxxxxxxxxxx>
Sent: Thursday, December 25, 2014 5:32 PM
Subject: Re: {Collins} 75A-1 deafness


Very good point Teran.  Should have thought of that.
The 75A-1 is designed for balanced feed (mostly) about 300 to 450 ohm feed
line. You need to use that 400 ohm to 75 ohm inline oldie TV transformer to
get a good match.  The newer ones that are designed for cable and have
better low end are better on 160 and 75 meters.

Don't know how that plays into your issue Max.

Bill

-----Original Message-----
From: Collins [mailto:collins-bounces+wcarns=austin.rr.com@xxxxxxxxxxxxx] On
Behalf Of Teran Hermanson
Sent: Thursday, December 25, 2014 5:42 PM
To: 'Max Cotton'; COLLINS@xxxxxxxxxxxxx
Subject: Re: {Collins} 75A-1 deafness

HI all and Merry Christmas from North Dakota

Max M0GHQ

The 75A-1 is a fine receiver and looks so good next to the 32V2.
I went over my 75A-1 some years back, it just seemed to be weak on receive.
After pulling it from the cabinet a few times and checking alignment and
tubes I read on here about a trick that worked for me.
I found an old 75 ohm to twin lead TV adaptor transformer and put it in line
with my 75A-1 and never looked back.
It made so much difference in receive strength both on the S meter and ears.
It equals my A-2 and A-3 now.

Good luck with the 75A-1.
73 Teran KF0HR



-----Original Message-----
From: Collins
[mailto:collins-bounces+twhermanson=stellarnet.com@xxxxxxxxxxxxx] On Behalf
Of Max Cotton
Sent: Thursday, December 25, 2014 11:31 AM
To: COLLINS@xxxxxxxxxxxxx
Subject: {Collins} 75A-1 deafness

Firstly, a very Happy Christmas to everyone on the reflector, hope you had / are having a great day. I decided to tackle my 75A-1 receiver this afternoon
as it is profoundly deaf, I have been meaning to get to this for sometime.
Swapping out some of the caps I am finding that most are fairly within
tolerance, although they maybe leaky causing the problem, question I have is
in the RF section, are the mica caps reliable as they look a bit of a
challenge to remove/replace, non look blistered or cracked, I don't want to
overdo this but am wanting to restore it to at least near to its original
receive capablities. I did try peaking it up before this and it remained
weak receive.
73, Max
M0GHQ


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