On Thu, 18 Nov 2004 02:23:43 GMT,
(Jason D.) put
finger to keyboard and composed:
There are no thru-holes. All components are smt. The mechanic says an
instrument specialist told him that these flex cables are known to
separate in normal use, probably due to heat and vibration. He claims
these units are irreparable.
Here is a photo of the PCB:
http://members.optusnet.com.au/~fzabkar/pcb_trace.jpg
The connection point is above and between the two lamps. The traces go
directly to a microcontroller. Note that there are numerous test
points which look like thru-holes, but I believe these could be for
bed-of-nails testing (???).
Yes, those "bumps" are for the bed of nail test points.
Looks like the ribbon and the pads on the circuit board are good, Why
not do a low-temp soldering?
My patience and eyesight aren't good enough for this. In any case an
email from a kind gent has cleared up the mystery for me. The
connection method is 3M Scotch 9703 conductive tape:
http://products3.3m.com/catalog/us/e...er/output_html
"Tape 9703 is an isotropic, electrically conductive, pressure
sensitive adhesive (PSA) transfer tape. It is a permanently tacky
system consisting of a PSA matrix with aligned conductive particles.
These particles allow electrical conduction through the adhesive
thickness ("Z-axis"), but not in the plane of the tape."
Next time use a good older program like photo shop pro 5.x (ebay
hopefully) to crop it (this chops off the unneeded pixels) then shrink
it down to 50% to cut down bytes, 30% is minimum for smallest size
without losing too much details.
Sorry for the abysmal quality. I should have made better use of Paint
Shop Pro, and I should have taken more care with the photography.
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
--
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