EQ4 mount problems

[Sharnbrook]

I have managed to solve one of the problems that I mentioned in my recent post, and I now have my EQ4 "working". The only problem is that it runs backwards, as it is a northern hemisphere version, and doesn't have a reversing button for antipodean use. Can anyone point me in the right direction for fixing this? I have done a number of web searches, but can't find any helpful instructions. Thanks for any help.

[davewaldo]

I don't actually know if this will work... but seeing as it runs of a DC battery, would it work if you switched the polarity of the wires on the battery, or if you use multible batteries, could you put them in backwards?

I don't know if this would work or if it might damage the unit. So best to confirm with someone else before tying it....

:)

[[1ponders]]

Do you have a brand or similar description of the motor setup Mike so we can check out the details? Have you opened up the hand controller and had a look in there? I know that Losmandy do silly things like that, putting the N/S switch inside the digital drive :mad2:

[Sharnbrook]

Davewaldo, Hmm, that's where I went wrong first time round. I thought that it would be OK to reverse the polarity and drive it backwards. That action fried the innards, so I won't try that again. In fact, I have had a fail safe installed, so it can't happen again. Thanks for the suggestion, but no thanks.;)

Paul, whole unit was supplied by Zhitong, and I have written to them to ask what to do. Whilst they have acknowledged my email, they have as yet offered no advice.

The controller says it is a "QHY STEP MOTOR CONTROLLER VER 1.3" and the stepper motor is an "EM ST30/ 12VDC, EVER MOTOR, 500 ohms".

I have opened the controller box, and there is no switch inside, (that probably means it isn't a Losmandy in disguise;))

I have attached a few shots of the equipment, in case it means anything to anyone, but I can't see that it's likely to help much.

Thanks for the suggestions though, keep 'em coming.

[[1ponders]]

Hm, not so simple then. :(

I'm intrigued though, what does the function button do?

[mill]

The only way it can be done is in the pic chip or reverse the wires of the stepper motor.
Is it unipolar or bipolar ?
Can you make a photo of the wiring that comes out of the motor please?
Steppermotors work by energizing the coils one after the other and if you turn the coils around it will run backwards.
After a search on the www for this motor it looks like i can't find any specs for these motors :(
Are there 4 wires coming out or 6 ?

[Terry B]

Could this have been made by the same QHY that now makes CCD cameras. It might be worth asking him. He is very helpful and can be found via http://qhyccd.com/

[Sharnbrook]

Well Martin, in answer to your first question, I don't know, and what's more, I don't know how to ascertain this. Maybe the answer to your second question will help, but I suspect it won't be of much use, because it has 5 wires, not 4, and not 6. A shot is attached, but as the motor is a crimp sealed unit, I cannot show the internal wiring. Thanks for your help so far.

[Sharnbrook]

Terry, Thanks for your suggestion. I have emailed QHY to see if he is the manufacturer, and have explained the problem. I shall let you know how I get on.

[Sharnbrook]

Hi Paul,



I don't have instructions to hand, although I think I can locate them somewhere. I did work out what it was for, but can't remember offhand. I shall try to work it out by trial and error. (Probably lots of error)

[mill]

Mike one wire will be the common wire and the other four go tothe coils.
http://www.doc.ic.ac.uk/~ih/doc/stepper/others/
See above website.

[Sharnbrook]

Thanks Martin, I have also received a reply from QHY, and he says that he was the manufacturer, and says much the same as you,

"Hello,
This EQ4 is designed many years before. To reverse the direction.You can modify it as the follow method.
The step motor has five wires.
1 Common pin
2 driver A
3 driver B
4 driver C
5 driver D


You can exchange the pin to :

1 Common pin
2 driver D
3 driver C
4 driver B
5 driver A


Or
1 Common pin
2 driver B
3 driver A
4 driver D
5 driver C

But I am not sure which method is right.You need have a try."

So thanks to you all for your very helpful advice.

[Terry B]

Good luck with it.

[Sharnbrook]

I have now managed to re-wire the motors, and it seems to run OK. It definitely runs the correct way, but whether the timing is right, I shall have to wait for some clear skies to find out. It's raining in Brisbane at the moment.

Later, I have driven it in the shed for an hour, and it has turned 1 hr on RA, so it is as good as I can expect.

In case anyone else ever has the same problem, for the Zhitong drive, the RED wire is the common wire
ORANGE is drive A
YELLOW is drive B
PINK is drive C, and
BLUE is drive D
This is for the NORTHERN hemisphere.

The sequence that seems to work for the SOUTHERN hemisphere, is to alter the connections so that the outside
RED wire is still the common wire (which does not move,) and is next to the
BLUE wire (drive D) which is next to the
PINK wire (drive C) which is next to the
YELLOW wire (drive B), which is next to the
ORANGE wire (drive A) which is the other outside wire.

Thanks to all those who helped get this sorted for me. Much appreciated:):):)