Embroidery machine retrofit.

No eBay APP ID and/or Cert ID defined in Kunena configurationIm willing to try with the signal generator. And while I am gonna have printer cables I highly doubt I have a non standard centronics cable laying around.

What do I need to do with the signal generator? (If it helps I also have a pokit pro multimeter/oscilloscope.) Just feed a signal in on 2 and see if it comes back out on 4 or ?

EDIT:  From looking at this I do not believe there is any other connectors so I bet power feeds through the centronics connector as well. Don't recall if thats a thing on normal ones or not.

Janome is still around, maybe it's worth it to contact them and ask for data sheets on either the board itself (716- or the driver IC:s (SI-7200J)? A long shot, but getting data sheets would make things much easier.

I think pin 2 and 4 was assuming a standard 36 pin Centronics connector? Given the 50-pin port, I think you have to do some reverse engineering before hooking up a signal generator. Some things to start with:

* Which pins are connected to GND? (Measure continuity between pins and the PCB ground plane, marked as GND in lower right corner of pictures).
* Which pins are connected to power? (Power supplies and cables are not visible in the pictures; I assume that these are on the other side of the steel plate and connects to the underside of the board?) Find any external power supplies that connect to the board and measure the voltage(s) they supply, then see if you can find additional power regulators on the board. I.e. identify the power rails that exist on the board, and map out pins on the Centronics connector that connect to these.
* Which pins connect to pins on the driver IC:s? These are the ones you might want to hook up to a signal gen to see if you get motor movement. It might be tricky though if there are e.g. enable inputs that needs to be activated.

Ha! A search for Sanken 7200 gives a few results:

A - pin 7
/A - pin 6
B - pin 12
/B - pin 13
Power down (active high) - pin 9
GND - pins 8, 3, 6
Motor coils - pins 2, 4, 17, 15
Vcc - pin 10

Pin 11 seems to be some kind of clock input? Connects to a 555 circuit in the data sheet. Maybe for a high side charge pump? Anyway, finding which pins connect to A, /A, B, /B and figuring out if the disable input needs to be deactived through some Centronics pin should do the trick!

Im gonna see if I can clean off a table to work on this tomorrow. Tailgate was only good for a quick teardown.
There is a white box and transformer on top that is visible in the video in the first post. I will try and get measurements on the output tomorrow. (Assuming the white box is the power supply. Small chance it is a variable speed controller for the main motor.

The issue with reverse engineering it is while I have the ability to do a fair bit hardware side I would assume there is a protocol involved. If I had the controller it would be different as I have access to a multi channel oscilloscope that I could use to reverse engineer said protocol.

If I go linuxcnc (Or grbl or the like) I would need to get a pair of stepper controllers, Probably a variable speed controller for the main motor and that should be it. Maybe a lpt breakout board as I don't think I would need a mesa for this.

Ive got a stack of old 2008 era cash registers that should run linux cnc. (Pretty much a standard pc but they have like 4 serial ports and a parallel port as well as a touch screen.) If they don't work I have others but they are the handy ones.

Hmm, the above pinout is for Sanken 7200M. I see now that 7200E has a different pinout. I have not been able to find a 7200J datasheet. So caveats apply! But looking at the M/E datasheets should help give an understanding of the kinds of pins you are looking for at least.

Thanks. I made the mistake of looking for janome instead. Now that I looked for sanken instead I see the same datasheet.

I will see if I can hunt those traces down tomorrow.