[Collins] 75A-2 new to me

WA9VRH Larry wa9vrh at mtco.com
Wed Feb 9 04:44:05 EST 2005


Hi Larry,

In a separate email I will send you 2 schematics of the 75A-2. There were
two diffident versions with the differences in the first and second mixers
if my memory servers me correctly.  The 75A-2 manuals will be on the CCA
website soon. I am in the process of finishing the cleanup on them.

73 Larry WA9VRH
Collins Collectors Association Archive Manager


----- Original Message -----
From: "Dr.Gerald Johnson" <geraldj at ispwest.com>
To: <telegrapher at att.net>
Cc: <Collins at mailman.qth.net>
Sent: Tuesday, February 08, 2005 10:04 PM
Subject: Re: [Collins] 75A-2 new to me


> The low s-meter could be from leaky AVC bypass capacitors and time
> constant capacitors. And from weak front end tubes.
>
> Vintage receivers that tried to use paper capacitors for cathode and
> screen bypass capacitors in the RF and first mixer tend to have low gain
> on the higher bands. Sometimes replacing the papers with disc ceramics
> can make those states work much better. short leads are important at
> 30 MHz.
>
> It's possible that wiring around the NBFM adaptor is a product detector
> or an interface for one.
>
> Is there no schematic on the CCA manuals site?
>
> 73, Jerry, K0CQ, Technical Advisor to the CRA
>
> --
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.
>
>
>
>
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