[Collins] (no subject)

[Gerald]

On Fri, 2005-12-30 at 15:52 -0500, k2qde at optonline.net wrote:
> Bill,
> Most accurate way is to look at the solder connections on C106, 
> the three section electrolytic "can" behind the meter. If the 
> connections and solder joints look like factory perfection, then 
> you may reasonably believe it's an original. NO ONE I've met 
> outside the plant can solder a joint that good and clean!

Doing maybe ten solder connections a minute, 8 hours a day, they SHOULD
get good. Collins inspectors were tough and some of my soldering did
pass. More of my soldering in Texas left in completed equipment, mostly
the D to A converter of the 821A-1. This engineer could solder alongside
production line girls and lab technicians and did.

> If 
> it is original, grab a small mirror and look for the date code 
> along the side of that cap. For example, 0466 [or 6604] could be 
> April, 1966, or the 4th week in '66. All originally install dated 
> parts, such as tubes, crystals, etc., would have the same xx66 dating.
> Other indicators would be the service bulletin history.

Not every electrolytic maker used that code. Some used letters and the
conversion was not admitted. For a long time, I've had the practice that
if I couldn't read the date code on an electrolytic or if I could and
that date code wasn't within the last year, I wouldn't buy that
electrolytic.

> For example, 
> SB-8A, but not 8B or 8C would also put it around 1966. But again, 
> that's relative to whether they are factory installed. A keen eye 
> will tell. According to Bill Harrison (of Harrison Radio fame), 
> component dates average between three to five months prior to 
> production.

Might vary according to production rates at both Collins and the
particular component vendor. Just In Time wasn't yet popular, but its
likely when there was a larger order to be built over a year that some
parts may have been bought at the beginning of the year to be used all
year to take advantage of better prices for larger quantities. Then in
time periods of low production it might not take more than a week or two
for incoming parts to be installed and shipped. Or if a vendor fell
behind (crystals or tubes especially) radios might be built ahead and
those missing parts installed for final test just before shipping the
radios. In such a situation its possible that crystals and tubes might
be used to test and align many radios in turn with new parts installed
with a touch up of alignment just before shipping.

> That should put you in the ball park.

Far closer than Rod's erroneous serial number lists.

> Stu, k2qde

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer