Telescope drive motors that don't...

[Archangel]

Turning the problem in many ways... i'm still thinking of unsufficient current AND/OR voltage at the driver output. . . .

Hi Steve, that was where I was going by asking if the enable pins were held high, as I do not understand the assembler . . . I think those ports should not be pulsed . . .JS

[mister_e]

i just had a look at L293D... there's an interesting voltage drop.. typical Vs-1.2 to Vs-1.8 v... ok ok @0.6A... but... could this be enough to lost most torque... i would think.

Probably the original design used MOSFETs, so the voltage loss was reduced to a minimum. Pure guess here.

[mister_e]

There's still some Sound-Card based Free software you could used... it's still better than nothing. Be carefull with signal amplitude and it should give you some pointers.

I already used VA (Visual analyser)
http://hacca.altervista.org/

[Dodgy Geezer]

Wow! A free oscilloscope! Thank you, Mister-e! Now I must find an old sound-card....

"Probably the original design used MOSFETs, so the voltage loss was reduced to a minimum..." - I thought I was actually building the original design. You will clearly see +6v on the original circuit diagram. But I am now inclined to think you are right, and this circuit does not actually work as specified...

[mister_e]

Well it has to work as expected with HIS OWN step motor... but how many different model is there in the world?

You can now buy a sound card under 20$ here... 1/10 of almost any decent used scope.

When i talked about the original design, i meant your previous one... not the one you found and post here.

[Dodgy Geezer]

"...but how many different model is there in the world...?"

He is using a standard chinese clock-drive for an EQ4/5 scope - so am I. I was expecting our motors to be identical....

"You can now buy a sound card under 20$ here.."

I have some separate sound cards already - I was assuming that you plugged the probes into the game port on them. But now I have downloaded VA, I see there is no info about where to connect the probes to at all. Do you connect the probe to the 'microphone-in'? If so, I can connect it to the built-in sound card on the motherboard of the system I am using. It is odd that there seems to be no information about this vital point...?

"When i talked about the original design, i meant your previous one.."

Sorry - I misunderstood. In fact, I still have the original handcontroller. My problem is not that it was broken, but that it drove the motors at the correct speed for an EQ4/5 mount (1/10 rpm) and I wanted to use it for an EQ3-2 mount (1/11 rmp). Those are the final speeds - there is a gear train of approx 200:1 between the scope and the stepper. The original controller used an Amtel micro, directly driving an array of 8 transistors. They could well be MOSFETs.

[mister_e]

you plug your probe to in Line in, make sure you set your Soundcard Mixer properly as well.

In VA, Click on Settings>> In/Out Device to confirm your setings.


Trent, i can't tell, it worked for me awhile back, not sure about the current one...

EDIT seems that I had the same version... doesn't seems to bug here.

[T.Jackson]

Trent, i can't tell, it worked for me awhile back, not sure about the current one...

EDIT seems that I had the same version... doesn't seems to bug here.

Try resizing some of the windows. Maximize the main GUI then restore, then manually adjust it. Sometimes messes real bad. Same problems with the tool windows too, like for the voltmeter.

[T.Jackson]

There's still some Sound-Card based Free software you could used... it's still better than nothing. Be carefull with signal amplitude and it should give you some pointers.

I already used VA (Visual analyser)
http://hacca.altervista.org/

That GUI is real buggy on my machine.