A wise man once told me, "Every time you break a wire it costs you money and
causes problems". He was right the cost of the connector and the cost of the
troubleshooting when the connector fails.
Scott
On Saturday, December 5, 2020, 7:23:10 PM CST, Gregg Eshelman via Emc-users
<[email protected]> wrote:
In the 1990's I fixed so many computer mouse cords. They'd get a broken wire
where the cord exited the mouse. Often the problem was caused by the cord being
too well restrained so it could only bend right at the exit point so often a
bit of plastic carving was done to make sure it didn't break a wire again. An
odd thing I noticed was only the cheaper mice ever used a molded strain relief
on the cord. Microsoft, Mouse Systems, etc didn't.
I even repaired the switches. The flat ones with a button on top had a metal
snap dome inside, which would crack. Some careful work with a knife and
superglue was done to transplant good domes from right switches on very dead
mice to left switches on mice with just the bad switch.
But then the price of mice went way down so it was no longer worth it to fix
them.
On Saturday, December 5, 2020, 03:51:46 PM MST, Karl Schmidt <[email protected]>
wrote:
>> Unfortunately the wiring is very simple in this machine. (It's just a small
>> sign router.) There is a main control
>> board, with a couple of daughter boards (one for coms the other is the main
>> brain) the encoder cables are plugged into
>> the main board, as are the limits, and some other misc IO. Then there are 3
>> ribbon cables one for each amp. That it.
>> I've checked the integrity of the ribbons and they all seem fine. There
>> isn't a bunch of individual wires anywhere
>> that one could come loose and cause this. The amps only have 4 other wires
>> 2 for the motors and 2 for the DC supply.
>
> You might check the states of the inhibit outputs, that seems to be the only
> way the drive signals a fault.
Most electrical hardware problems turn out to be connectors. Also - on
machines that move/flex wire - proper strain
relief is a must - and a lot of equipment is made with the wrong type of wire -
if it flexes too many times - like on a
router - wires break (usually right at the connector or some strain relief) .
There are people that make $pecial wire for robotics - but if you don't need
documentation, just use wire with lots of
strands ( I've used 22ga with 60 strands) and strain relief to limit bend
radius - the bits that matter. I used
silicone wire from bntechgo to fix a 3D printer that wiggled itself to death.
(This is the type of wire they make test
leads out of so fidgeting technicians don't create intermittent connections)
Automation Direct has some shielded high
flex wire.. (didn't have to buy a full reel).
But more important than the wire - it is where the wire meets the connector
that fails - or where the connector meets
the circuit board. ( I once made a small pile of money fixing some Chrysler
instrument panels - they would develop
cracks in the solder on the connector joints - intermittent - so very hard to
diagnose - I had to use a microscope to
actually see most of the cracks - remove and replace the solder and all was
well)..
PCB to connector joints with early no-lead solder were particularly bad ...
Most of the other wire in a machine - even if it vibrates a bit, you can get
away with MTW type stranding.
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