On Fri, 19 Nov 2004 00:27:34 GMT, (Jason D.) put
finger to keyboard and composed:

Here are the same photos with better processing:
http://members.optusnet.com.au/~fzabkar/pcb_trace.jpg (33KB)
http://members.optusnet.com.au/~fzabkar/flex_lead.jpg (19KB)
http://members.optusnet.com.au/~fzabkar/flex_lead2.jpg (17KB)
http://members.optusnet.com.au/~fzabkar/label.jpg (13KB)
http://members.optusnet.com.au/~fzabkar/instruments.jpg (13KB)

Cheers,

Wizard

I wonder if Scotch 9703 conductive tape may be a viable solution for
repairing broken flex leads?


- Franc Zabkar

That special tape will work! Key is clean both real good. Careful on
that flex cable, it is made of conductive paint printed on clear
plastic sheet. Many chemicals will attack that paint. This is same
kind of flex circuit with this printed on conductive paint.

Otherwise, there is room on PCB to drill two holes and use two thick
(say .050" to .100") strips of aluminum and screws & nuts, one thin
rubber strip from your junk stuff to pad the flex so both flex and
circuit board is squeezed together. Much better design IHMO!!

This is what 3M's 9703 datasheet has to say about "mechanical
clamping":

"To assure electrical resistance stability of tape 9703 in any
flexible circuit interconnection application, a mechanical clamp
should be considered in the design of the application. Without
clamping, over time, any shear stress or temperature excursions
applied to the bond line could result in an electrical open in the
bonded circuit. A well designed mechanical clamp will reduce the
environmental stress on the bond line and improve the electrical
reliability of the bond. Several types of mechanical clamps have been
used successfully including foam strips attached to lids or cases and
screw attached plastic clamps."


- Franc Zabkar
--
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