With many thanks to a forum member who today met me half-way to do some test fittings, I expect to confirm later tonight that the cause of the problems is a very simple assembly error. 6 out of 8 kits worked and another 2 returned kits now work, after having previously had their wires tugged and pulled trying in vain to find the faults. I suspect that when soldering loom wires to the base of the connector header pins on the circuit board that wire insulation has been sufficiently softened by the heat to allow it to be inadvertently pierced by an adjoining header pin when pressed into position. The proof will be to detect a short in each of the 2 failing kits at the connector then find the pierced wire under the circuit boards.
Edit: A comprehensive loom test jig is being developed but in the meantime continuity checking between adjacent connector pins should prevent any further faulty kits from being supplied.
Another edit: Yes, source of problem has been confirmed - a different pair in each module though. Moving again...
August 9th: A loom tester has been developed which will detect any crossed or joined wires and any wires incorrectly positioned in the connectors, which will prevent assembly errors from going unnoticed.
Last edited by LLAMS; 09-08-2015 at 04:43 PM.
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