Re: 7d01 with df1 garbled display

Craig Sawyers <c.sawyers@...>
 

The flat cables I
mentioned are the standard ones you'll find everywhere in older Tek
equipment. I put a picture at
http://w1.871.telia.com/~u87138090/Flatcable.jpg but it is very
difficult to visualize the difference with a picture. You'd really
need to see them both in real life and compare. The green is the bad
one and the blue is OK.
This is very reminiscent of the problem with one design of connector that
Lucas invented for Jaguar in the 1970s. The idea was that the cables were
crimped into either bullets or sockets, and these were assembled into an
array held in place by a moulded rubber housing.

Now although nominally gas tight, they progressively fail. Some stay OK,
but at random contacts can measure an ohm or two - upwards to open circuit.
This can be disastrous with ampere currents in automotive circuits. Because
housing is a moulded block around contacts it is impossible to solder the
crimp area - so the only way to solve the problem is to chop off the old
mating pair and replace with a good quality modern locking connector.

The failure mechanism might be to do with compounds in the rubber slowly
oxidising the copper, or it could be heat and humidity - or a combination.
Whatever, it is a sod to find (like the tek crimp problem).

Craig

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