Ron wrote in message
...
Eeyore wrote:


p.p.s The hairline crack around soldered joints is especially common
where the
drilled hole size is not ideal ( oversize ) for the lead diameter. I
have seen
manufacturers specify hole sizes very poorly with the inevitable
outcome. Hence my
PCB footprints often use my own estimation of the appropriate drill size
rather than
the data book one. Plenty of other people do the same.

Graham



My Dad - who taught me to solder some 50 years ago - use to say that a
good solder joint started off as a good mechanical joint.

As a teeenager, I probably spent thousands of hours wiring up
uniselectors and GPO relays with tinned copper wire and sleeving, on
every joint, the wire was either wound around the tag or passed through
a hole, if it was a lead through a circuit board, the wire was bent over
at right angles on the solder side.

We manufacturerd slot machines btw.

Ron


Very true , unfortunately assembly time/cost preclude that.
Hence the notorious guitar input socket problem. The sockets used to be
wired between the chassis mounted socket and pcb , so mechanically decoupled
from routine use of the socket. Now all soldered to the board and the
insertion/removal forces are transmitted to the pcb solder joint.

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