Modifying Printer PCB board.

happyuser123

Hi,

I have a epson c88+ printer, I am trying to modify the Allegro A3977 Microstepping Driver, to move the incoming signal for the stepper motor and send it to 2 additional stepper motor drivers, so that I can run 2 stepper motors off that same signal.

I have little experience in this field and I would greatly appreciate your kind help and support in guiding me true this project.


Thanks in advance!!

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NoTime

Welcome to PF.

From the pic it looks like 4 wires going to the stepper.
Is one pin connected to the ground plane/Vcc or do all 4 go to the IC.
You probably need an oscilloscope to check the pin relations when operating or you might get the same info from the stepper motor specs if you have that.

In the first case you can probably use three transistors as switches.
in the later you will probably need to use two pins to drive H-bridges.

happyuser123

Hi,

the stepper motor that's now connected is this: http://www.shinano.com/xampp/docs/SST41D.pdf

Also, how would I power the motors? and add that second driver for the second new stepper motor??

happyuser123

If it would be possible for you to draw a quick diagram, so that I can understand your suggestion better, that would be extra greatly appreciated!!

Thanks in advance for everyone that's so kind to help me with this project!!

happyuser123

I found the diagram for the driver that I am trying to switch the signal from/currently on the board:

http://www.allegromicro.com/en/Produ.../3977/3977.pdf

happyuser123

I am looking for the most economocal option for the project.

I would also greatly appreciate if you can please also list everything else I will need for this to work.

Thanks again!!

NoTime

Ok, That's fairly complicated.
I suspect the simplest solution would be to get a couple more of these chips, replicate the chip local support circuitry, and fan out the original control lines to the new chips.

The other option looks to be designing a unity gain h-bridge current amplifier as this does not look like simple on/off step switching. Page 41 of the motor datasheet probably has more info on this, but you didn't include that page.

Good luck.