N_Cook wrote in message
...
Bob AZ wrote in message
...
Got a call to fix an Outdoor LED School Sign. Never worked on one and
need to get smart about them.

The sign is outdoor of course and has a computer to program it from
inside in the office. Apparently the computer and monitor works well
but the sign is only half there. Not sure which half. Sign is 4 years
old.

Any input will be appreciated.

Thanks
Bob AZ


I tried repairing one where damp air had got inside and corroded pins ,
mainly on the data line expander chip , inside the sign. So parts of
letters
were missing. Removing the big chip , abraiding pins, and soldering to an
intermediary turned pn socket worked for a year or so and then corrosion
got
down inside the encapsulation - could not find a direct pin for pin
replacement, but with some research a functional replacement could
probably
have been found.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/




By expander I think it was something like expanding 8 data lines from the
serial
receiver up to 96 lines for 80 columns and 16 rows or whatever the matrix
was, so sometimes column/s would be missing and sometimes row/s missing


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/