View Single Post
  #13   Report Post  
Posted to sci.electronics.repair
Jeff Liebermann Jeff Liebermann is offline
external usenet poster
 
Posts: 4,045
Default the importance of truly clean contacts

On Wed, 11 Apr 2012 10:41:38 -0700, "William Sommerwerck"
wrote:

The following might be of interest. More likely it will provoke a "Duh. I
knew that." response.


I know everything.

A fair number of phones use an 18 pin connector:
http://pinouts.ru/pin_CellularPhones-A-N.shtml.

As a side biz, I resell used cell phones. The most common problem
with the big wide 18 pin connector is pocket lint, dirt, and general
crud in the telephone end of the connector. The telephone end has
gold wire contacts, which are easily buried under the crud. A blast
of air, and a stiff acid brush with some alcohol or 409 cleaner is
usually sufficient. The charger end also gets dirty, but since it's
less likely to be carried in the pocket or used to stir crud, it tends
to remain cleaner than the phone. Same fix as the phone. Use an acid
brush and some cleaner.

There is also the problem of the contact wires getting bent out of
line. These wires are held loosely in place by a plastic frame. The
problem is that walls of the frame are rather flimsy and can be
trashed by inserting the connector backwards, stepping on the charger
connector, or trying to fix the connector with a blunt instrument.
Once the wires are bent, it is rather difficult to return them to
their original position.

You can usually tell if it's clean enough with a big magnifying glass,
microscope, or USB closeup camera.

The moral of this? I guess it's that because the bottle's label reads
"contact cleaner", doesn't mean it really cleans contacts.


Rub and scrape please. Your clothes don't wash themselves by simple
immersion. I would not expect connectors to clean themselves by
simply applying some magic cleaner. You need to rub, scrape, and
agitate the cleaner over the connector. Your clothes also don't stay
clean if you forget to rinse afterwards. Try to blow out as much
cleaner as possible, and then add more to rinse out what's left. Most
cleaners just soften the goo, which must then be removed.

On the other foot, any phone that uses an 18 pin connect has to be at
least 10 years old. I can see why the Sprint people didn't want to
deal with it. The average lifetime of a cell phone is about 18 months
(30 months for a smartphone). You might want to consider an upgrade.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
#
http://www.LearnByDestroying.com AE6KS