On Sat, 6 Feb 2010 17:40:02 -0000, "ian field"
wrote:


"Mycelium" wrote in
message ...
On Sat, 06 Feb 2010 14:44:53 GMT, Bob Quintal
wrote:

When I look at the picture labeled chip-cap.gif, i see 2 horrible
looking solder joints. There is insufficient solder. The solder is
crystallized. There is insufficient solder in the meniscus.and it
shows evidence of insufficient heating I do not see any perceptible
bulging out of the cap at either end.

You obviously are unaware of the new solder joint acceptability spec
for RoHS assemblies.

Grainyness is the norm. Also, "modern" motherboard houses have been
using stencils that are too thin for years, so they have all been low on
solder for a long time.

There is no such thing as a clean, bright, shiny solder joint any more.
The days of 63 / 37 perfection are gone.

44780 style LCD modules seem particularly intolerant of lead free solder.

A relative, always looking out for bargains, picked up a DAB radio alarm
clock "reduced to clear" - on getting it home they found it was pretty much
unusable with the LCD not working, so they passed it on to me for the same
as they paid.

When I opened it up and attempted to pull the LCD's ribbon cable connector
from the PCB receptacle, the ribbon cable pulled out of the solder joints on
the LCD module instead.

The same relative also has another DAB radio that has an intermittent LCD
backlight, and I have a music centre with dim backlight and intermittent
display.


I still sometimes reminisce about the days of 'zebra strip' attachment
of LCDs, which made them very serviceable. :-)

I had a calculator given to me that failed due to Coka-Cola spillage,
and I took it apart, and cleaned up the strip and strip attachment area,
and reassembled it , and used it for a decade after that. It may still
be around somewhere in storage. I think it was a TI-30 or 35.

Too many solar powered now to keep old battery powered types around
anymore.