[Collins] s line trim rings

[Dr. Gerald N. Johnson]

On Sun, 2008-11-23 at 19:14 -0600, Carey Lockhart wrote:
> hello drake collectors,
Well, there might be some Drake collectors here, but most of us are
Collins collectors and users.
> 
> my name is carey. my call is kc5gtt. i am located in boerne texas. i
> have just traded for my first collins s line. as i had expected they
> are going to need some tlc. i have cleaned up the chassis of the 75s1
> with 409 and washed residue off with water. this worked very well.
> there is a mod that has been done. there is a 6ba6 added between L4
> and T1 does any one know what that may be for? would it be better to
> remove it or call it good?

Probably for more IF gain. But in my 75S-3B, I lowered the gain at that
point once I put in a very low noise second mixer to enhance the strong
signal handling of the receiver. The second mixer is a weak spot for
strong signals and contributes considerable receiver noise.

Its unlikely that you can make the receiver exactly original unless that
tube was mounted on thee accessory plate and you can find another
accessory plate (place for Q multiplier or noise blanker).

> also i have two different trim rings around the faces of the 75s1 and
> 32s1. one is sort of white and the other is grey. should they be
> different?

The trim ring should be gray but a lighter color than the case.

> one last question is about adding photos to our post. is this ok or
> should i just add a link to photos. sometimes a picture make it easy
> to get the point across, especially when you haven't a clue what your
> taking about. hihi any help will be most appreciated.

Most mailing lists these days won't pass a photo or large attachment
because spammers would kill off the users with large spam, virus, and
trojan horses. Its best to post a picture to a publicly accessible
server and send the link to the picture. Then those of use with slow
dial ups won't sit here wondering about taking half an hour to get our
e-mail.
> 
> Carey Lockhart, KC5GTT
> kc5gtt at gmail.com
> www.kc5gtt.com
> 
In general, the 75S-1 will need the black beauty oiled paper capacitors
(C8, C97, C50, and C102) replaced with orange drops. Those old
capacitors are leaky and upset the receiver operation. They are
cylindrical, molded black plastic, with color code stripes. Then all the
electrolytics are even more suspect unless replaced which is not easy
for the ones in cans.

Then switch contacts need cleaning with a quarter drop of DeoxIT each.
All the tube socket and ground lug mounting screws need to be tightened.
It won't hurt to clean tube and crystal pins with minuscule bits of
DeoxIT also. Alignment of trimmers may prove to be difficult from them
sticking. DeoxIT applied to their rotation connection underneath the
chassis can help them work, if they will turn. They will be the weak
point of the receiver after fixing the papers and electrolytics.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer