Re: Roomba 570 problems

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Dan Lanciani" <ddl@danlan.*com> wrote in message
news:1348091@xxxxxxxxxxxxxxxxxxxxxx
> In article <YoWdnQaXUIu1M4LVnZ2dnUVZ_uKpnZ2d@xxxxxxx>,
ROBERT_GREEN1963@xxxxxxxxx (Robert Green) writes:

> | > I decided it was finally time to try a Roomba so I got a 570 from
> | > Hamster Schemer.

(My spell checker decided to rename your vendor and it was too funny to
correct.)

It worked for about an hour total and then
> | > one of the wheel modules seemed to lose the ability to move in a
> | > forward direction.  This made the Roomba turn in a tight circle
> | > until it gave up.  There was nothing obviously mechanically wrong
> | > with the wheel module (it turned freely by hand) and when the Roomba
> | > tried to turn it the wheel did stiffen up (as determined by my hand).
> | > Maybe part of a bridge driver had failed?  Anyway, Hammacher Schlemmer
> | > exchanged the whole package for a new one.
> |
> | FWIW, in reading up on your unit this weekend, it seems there is a
tendency
> | for hairs, especially long ones, to wrap themselves tightly around the
brush
> | and wheel shafts and trigger the motor stall sensors.
>
> I removed the wheel module; there was no obvious mechanical problem.

I suspected it wasn't your problem, but it afflicts a lot of people, and may
yet bother you.   The next place I would look would be a bad connector but
you're ahead of me in the disassembly process so it's just a hunch. One
would think that the boards are either Go/No Go and the failure point is
likely to be the assembly or shipping process.  Especially for two in a row.
Something not getting connected properly or banged loose during shipping.

> | If you put the unit on a table ledge so the cliff sensors sense "solid
> | land," you can put a wheel in each palm and guesstimate the torque.
>
> I did quite a bit of that.  When it wanted to turn the wheel forward it
> managed to tense it up a bit but nothing more.  Backwards worked.  I
> tried controlling it with the remote as well.  My first guess would be
> that part of the driver circuit had failed.

Do you think the individual units are tested during or after assembly or QC
is by random pulls?

> |
http://forums.irobot.com/irobothome/board/message?board.id=80&thread.id=2389
> | &view=by_date_ascending&page=2
> |
> | talks about brush problems.  Do you have two different size roller
brushes
> | and are they bristle or rubber paddlewheel style with four vanes?

> > One brush, one rubber paddle wheel

You've not even experienced the joy of the small bristle brush and how much
rug fringe it can eat.  (-:  They're obviously learning.  Can you return it
and get a few 4300's?  I recently saw them for $89 at Outpost (ptooey!).  I
am convinced people should get the very latest and greatest from Roomba
because of all the "slipstream" changes to firmware and hardware.  They've
made some serious advances in the ability to decelerate before colliding
with an antique table leg and knocking a chip out of it. )-:  (very low
SAF!)  They've also made changes in edge navigation - the DirtDogs get stuck
on the mat in front of the dog bed religiously but the Red 4300 does not.
They look very similar drivetrain-wise so I assume the difference is in the
processing of sensor data from the wheels.

> | It seems
> | that iRobot replaces bristle brushes with rubber flapped ones when
owners
> | complain.
>
> Apparently they replace the entire brush module quite a bit, but I don't
> think it would have helped in this case.  The motor wasn't even trying to
> turn.  I suppose it could have burned out, but again it felt like a driver
> failure.

Having recently traced a bizarre intermittent in a PC to a bad crimp in a
Molex drive cable power splitter, I'm now hitting all problems I encounter
with my "it's a bad connector" hammer.

> | I've gathered that a lot of problems surface in the first few runs of
new
> | ownership due to the typically high initial "dirt load" in the house.
>
> I would have hoped that all the drivers were protected against even
complete
> motor stalls.

They seem to be.  I perhaps should abuse the one I am about to send back to
see what happens when wheels are clamped and can't spin.

> | Let us know what happens.
>
> I have unit #3.  I haven't run it much yet; I'm sort of afraid to.  If
> things don't settle down after six months (when the free shipping stops)
> I'll probably give up...

Too bad.  I would have suggested the fleet paradigm, for reasons stated
previously and for the spare parts.  I figure for every four I buy, I'll
effectively getting six because I should be able to repair two for close to
nothing - unless, of course, it's always the same part that fails.  It's
also pretty amazing just how fast five bots can clean up a house, especially
with a human bot herder following them around with a cooking pot brush
attached to a long stick to root out corner dirt, the Roomba's Achilles'
heel.  What I really need now is a cornerbot that seeks out wall
convergences and has a specially designed proboscis for cleaning inside
corners.