[Collins] Collins RF Mixer

[Chris Kepus]

Thanks for the replies.  A set of pictures for this unit are still on eBay -
item # 181293735908.

After it's in my hands, I'll draw the circuit and share.

As was mentioned, given its "RF Mixer" nomenclature combined with "test
equipment" markings, I also speculated that it could be anything from a
means to allow testing of proposed miniature mixer tubes in an octal tube
radio to possible product detector applications....

It was too intriguing to pass up. ;-)

73,
Chris
W7JPG

-----Original Message-----
From: Dr. Gerald N. Johnson [mailto:geraldj at weather.net] 
Sent: Saturday, January 11, 2014 8:24 AM
To: Francesco Ledda
Cc: 'Chris Kepus'; collins at mailman.qth.net
Subject: Re: [Collins] Collins RF Mixer

ALL Collins part numbers refer to a drawing, from wire to nuts to radio
systems. If the family begins with 5 its a drawing of a part or a unit bill
of material or a manual designed by Collins. All other families identify the
type of the part by the family, like 745 for carbon composition resistors
for which there IS a specification drawing. Before about 1963 the -00n was
usually shown as without the n but the drawing included a number 1 to 5
which designated the paper size of the drawing,
1 being 8-1/2 x 11, 5 being something like 30 x 36, the size of the standard
drawing board, a big sheet. A specification drawing for say 1/2 watt carbon
composition resistors would have maybe 100 four digit part numbers all
ending in -001 on letter size paper. As new parts were added it was noticed
that there weren't all that many four digit numbers left so when I had a new
specification written for 1% carbon film precisions resistors to include all
the 1% values that I needed for metering circuits (the existing
specification included only every other value) that it came with that family
number (I don't remember it now, doesn't matter), and ONE 4 digit number and
used as many suffixes as needed to show the individual values.

In the original inquiry and the picture the .00 suffix does not fit the
rules for numbers as I understood them, should be a -00. Searching for the
first two groups gets many a phone number, isolating it by adding the words
Collins Radio Mixer gets two wrong hits in google. Adding the
-00 gets no hits with the part number in quotes. Most search engines treat -
as a space and so use the three number groups independently unless forced by
the quotes to make a phrase.

I can only surmise that the unit was made for production or service center
testing. It probably allowed testing a vintage radio with an octal based
tube that needed a mixer to get along with the standard frequency range of
test equipment by adding the auxiliary mixer with its coaxial input. If it
was needed for repairs in the field it should have been mentioned in the
operations/service manual for that unit and so if that manual has been
scanned and put on line somewhere google would know about it. My guess is
that the tube is a 6BE6 or 6BA7 and the coax goes to the mixer grid while
the octal base matches a 6SK7 or 6SA7 but with an external oscillator signal
on the coax, any amplifier tube will mix with the LO signal applied to the
signal grid, screen grid (unusual) or cathode so my guess can be off by any
amplifier tube in the tube manual. 
The case could hold a product detector, indeed could be a product detector
for some receiver with a 6SQ7 already. Show me the internal circuit and I
can have an opinion.

73, Jerry, K0CQ, Technical Adviser to the Collins Radio Association.

On 1/11/2014 7:54 AM, Francesco Ledda wrote:
> My 1982 Rockwell Collins Preferred Standard Part List says:
>
> Family 599
> - Test Equipment Drawings 9000 Series Newport Beach
> - Test Equipment Drawings 4000 and 8999 Series Cedar Rapids R&D
>
> Therefore, the number on the part is not a CPN, but refers to some
drawing.
> That drawing will tell you what the part is.
>
> If you can, email me a picture of that part. I may recognize it.....
>
> KF5RXV
>
> -----Original Message-----
> From: collins-bounces at mailman.qth.net
> [mailto:collins-bounces at mailman.qth.net] On Behalf Of Chris Kepus
> Sent: Saturday, January 11, 2014 2:11 AM
> To: geraldj at weather.net; collins at mailman.qth.net
> Subject: [Collins] Collins RF Mixer
>
> Jerry and David,
> Before I send out an email blast on this, I thought I should give two 
> Collins experts first crack at helping me identify a component I 
> bought that showed up on eBay. Please see the pictures attached.
>
> My thinking was to use this "package" and repurpose it as a plug in 
> product detector in one of my old boat anchors.
>
> But before I modify this I want to see if I can find out what it was 
> originally designed to do.  I was unable to locate any info on the 
> internet (much to my surprise) using the Collins PN of 599-2554.00.  Any
ideas??
>
> Thanks,
> Chris
> W7JPG
>
>