EQ5 Motor Controller

Hi

I have a Helios 8" on an EQ5 mount with dual motor drive.
Unfortunately the motor controller has given up the ghost. Long term
I might invest in a more sophisticated controller like the LittleFoot
(http://littlefoot.rajiva.de/littlefoot/indexs.html) but for now I
just want the simplest cheapest single motor sidereal rate controller
I can find - but I'm having trouble finding anything at the simple end
that will 'just work' with the EQ5.

Any suggestions? A simple circuit, commercial product or second hand
item are all options...

Cheers
Kev

wrote in message
oups.com...
Hi

I have a Helios 8" on an EQ5 mount with dual motor drive.
Unfortunately the motor controller has given up the ghost. Long term
I might invest in a more sophisticated controller like the LittleFoot
(http://littlefoot.rajiva.de/littlefoot/indexs.html) but for now I
just want the simplest cheapest single motor sidereal rate controller
I can find - but I'm having trouble finding anything at the simple end
that will 'just work' with the EQ5.

Any suggestions? A simple circuit, commercial product or second hand
item are all options...

Cheers
Kev


Why not look into getting it repaired , if otherwise it will be so much
junk,
assuming its an electronic failure rather than mechanical and not totally
epoxied in its casing. Is it just controlling 2 stepper motors with gearing
for 2 degrees of motion or is there separate feedback posistional signals
integral with the mounting.
To me they generally usually seem to need visual sighting onto a nearby
guide star , allowing for any backlash error, and then passing over to pc
control and not absolute positional control.
Whats the weight for sending by post?
Any reason for failure, water or condensation , excessive wind etc?
Is there (when working) any manual over-ride to the drive or is it only pc
control?
I've repaired control system kit like plotters/ sign cutters before ,
some past repair briefs, CV if you like
http://www.divdev.fsnet.co.uk/repair4.htm Repair Briefs- Test Gear,
Industrial & Boating Gear, Domestic, Miscellaneous, Computer
and repair, repair2 and repair3 files

A valid email address for me is on that URL, not whatever this posting
throws up

Otherwise the nearest I've come to astronomy kit was advising
Dr John Mason of the South Downs Planetarium on trying to replace a blown
"Sirius" and equivalent relays for the German ones on one of the projector
control boards.

On 5 Feb, 08:33, "N Cook" wrote:
wrote in message

oups.com...




Any suggestions? A simple circuit, commercial product or second hand
item are all options...



Why not look into getting it repaired , if otherwise it will be so much
junk,
assuming its an electronic failure rather than mechanical and not totally
epoxied in its casing. Is it just controlling 2 stepper motors with gearing
for 2 degrees of motion or is there separate feedback posistional signals
integral with the mounting.
To me they generally usually seem to need visual sighting onto a nearby
guide star , allowing for any backlash error, and then passing over to pc
control and not absolute positional control.
Whats the weight for sending by post?
Any reason for failure, water or condensation , excessive wind etc?
Is there (when working) any manual over-ride to the drive or is it only pc
control?

Hi

Thanks for the suggestion, I am reasonable at electronics my self but
have been unable to figure out what is wrong.

When you power the device on about 1 in 20 times it will drive both
bipolar stepper motors, the other 19 times it will do nothing (or
power the single dual colour LED to different shades of brightness).
When it does power on 1 in 19 times all the buttons work correctly
including the 2x, 4x, 8x switch but with no buttons pressed it drives
the correct motor at sidereal * 2 (or something about that) instead of
sidereal * 1!

The device is based around a microcontroller with I believe firmware
stored in it, the only other chip is a voltage comparator, a small smt
transistor, lots of larger transistors and diodes driving the motors.
Nothing is visually damaged.

More information he http://www.tejraj.com/EQ5_Dual_axis.pdf

The unit is I believe probably damaged by excess voltage being
applied, I plugged a 12v power pack into it instead of a 6v pack.

Thanks
Kev