Z-axis fubared

[D. Joe]

I have reached the limit of what I'm comfortable messing with, in terms of
the Z-axis operation.

It continues to behave the way it was last night, mostly: The Z-axis motors
will move things up, but not down.

I thought just making sure each of the four wires in the connectors at the
board were pushed all the way in would solve the problem, and it seemed to
be doing so, last night. But that doesn't seem sufficient, now. I don't
know if there's something else has gone wrong with the connectors, or not.

My impulse would be to plug the Z-axis motors into one of the other axis
controllers, and to plug one of the other axis motors into the Z-axis
controller, to cross check the controller, headers, connectors, and cables.
But, if a short has fried something in the controllers, I don't want to fry
additional controllers.

So, I'm going to leave it as is, for now.

--
Joe
man screen | grep -A2 weird
A weird imagination is most useful to gain full advantage of
all the features.

[Brian Boucheron]

Okeydoke. If, when the axis travels up, it's smooth and "normal", not
jerky and weird, that would suggest to me that the stepper controller
is still fine. If, when you attempt to move down it just does nothing,
and not some herky jerky weirdness, I would be further confident that
this is an endstop issue.

I don't recall if the endstop is normally-open or normally-closed, so
unplugging it may either fix or exacerbate the issue. Either way it's
not a long-term solution of course, but it could be handy to narrow it
down to a loose connection 'round those parts.

-B.

ps: just a head's up when troubleshooting... so we avoid further
troubleshooting: most connectors are fine to diddle with "live" when
the machine is on... but please don't plug/unplug the stepper motors
when the unit is powered. That's a no-no. I have two or three spares
we can swap in if we indeed need to troubleshoot that particular part.

[D. Joe]

On Thu, Jun 21, 2012 at 07:21:29AM -0400, Brian Boucheron wrote:

> ps: just a head's up when troubleshooting... so we avoid further
> troubleshooting: most connectors are fine to diddle with "live" when
> the machine is on... but please don't plug/unplug the stepper motors
> when the unit is powered. That's a no-no. I have two or three spares
> we can swap in if we indeed need to troubleshoot that particular part.

Ah, that's what I was looking for. I remembered Alex said something like
"you can't really hurt anything, except for one thing: Whatever you do,
don't cross the streams".

But of course, it wasn't "don't cross the streams" it was something else.

I guess "don't plug/unplug the stepper motors when the unit is powered" was
what it was, instead.

Sorry, you did mention the endstop Tuesday night, I should have remembered.
I got all fixated on the idea that it was the individual wire termitions
coming loose in the connectors.

A much more disturbing behavior I've also seen is when the two Z-axis
stepper motors turn in *opposite* directions. Now, it may be that that is a
wiring fault in the connector, but because I'm screwing with them trying to
fix what might be an end-stop issue?

Anyway, thanks for the reminders. That gives me more to go on, when next I
get a chance to get in to try something.