AUTOSTAR INFORMATION Last updated: 10 April 2001

Motor Unit Failure on Power On

Sent:	Sunday, April 8, 2001 11:38:00
From:	rseymour@wolfenet.com (richard seymour)
[This message was in response to a situation where the Autostar would
display a Motor Failure error message right after displaying the Sun
warning.  Previous to this the AC power supply had been interrupted.]

Before trying a download (which will require an hold-the-keys on
 powerup override), try:

Test steps i'd try: (and -did- try, when mine fried)
Plug in the "default hand controller"... 
When you power up, it sits there blinking all of its lights.
Tap any slew key.
It'll try to move both the Az and Alt axis a few degrees, CW and UP.
(it's performing a Calibration step). 
If it can, and it gets good feedback, it'll simply stop and wait for
 you, with (most likely) the top light illuminated.
If that's what you see, then the scope electronics and motors are
probably happy.

If it encounters problems, it will blink all of its lights, and may
start repeatedly trying the calibration moves.
*Exactly* which symptom you'll get varies with whatever failure you're
experiencing.  Mine started circling clockwise, with no Alt motion.

Assuming the ETX passes the handcontroller test, suspect the Autostar.

Next thing: have you surpressed the Getting Started message?
The error message you're getting is probably from when the Autostar is 
attempting to perform a "deep reset"  motor calibration step.
(if you've never done one, it inserts it between the "Sun Warning" 
and the "Getting Started" messages...)

If it -is- attempting a calibration, it should display
"Testing Motors" on the display (perhaps very quickly).

It sends commands to move the Az CW, and then the Alt UP, and then
checks the values it gets back... if either test returns "255" 
(or minus one, depending upon interpretation), it declares a 
motor fault.  That "255" can arise from the motor circuits, or
a failure to communicate.

In v2.0h, it also locks that "bad" value into the "send next time"
memory location, so subsequent power-ups may also have problems.
I'm going to dig into that further... it might be a bug...

During normal powerup, the Autostar sends the Calibration info -to-
the ETX base.  There's no motion, it's merely sending the values it
attained back when you -did- a calibration.

After a full download, across a version jump (i.e. v2.0 to v2.1),
the locations in the Autostar's memory where things are stored during
power-off times changes... so if you install v21eK, you do have to
perform a RESET (or the Updater should do it for you... the current one
doesn't) to guarantee that things get placed in the new locations.
Wild rides are the consequence of not performing at least one RESET.

There are two forms of RESET: the one you can command from your Keypad,
and the one which the Updater can command.  The Updater can command
a -deeper- RESET than the keypad... the "deep' reset starts with a
 1-Jan-0000 (or 1990?) date, and automatically does a calibration.

When my ETX fried, the Autostar didn't declare a fault until after
setting date and time... only the Alignment step finally noticed that
the beast wasn't happy.

Now: the caveats: I suggest opening up the base and looking -closely-
for mechanical damage: the yanked power cord could have hurt the little
circuit card with the power plug (and RJ45 jacks) on it.
If i'd done that -before- trying my hand controller, i wouldn't have
damaged it, too (my problem was the RA clamp cutting thru the Alt
 wires... shorting lots of things together).

If you're handy with wiring, you could create a power-only cable for
the Autostar, and test it -without- the scope present at all.
All it takes is two wires into an rj45 jack, and that plugged into
the Autostar.  +9v (or higher) goes to the edge of the connector
closest to the rs232 jack, ground is the other end of the connector.
(so that's pins 1 and 8 getting power, all others unconnected).
Be careful, check your wiring and the final product with a voltmeter
before attaching, and you can run your Autostar without any Motors
to cause faults.

Ahh... did you participate in the Great Unplugged Autostar Experiment?
(i.e. turn on your telescope with -no- controller plugged in)
IF so, does the current behaviour differ from the past behaviour?
(-what- a scope did is almost random: some sat quietly, some ran
 at moderate speeds, with pauses, in circles and ascending barrels).

Good luck.
--dick

Return to the top of this page.

Go back to the Autostar Information page.

Go back to the ETX Home Page.