Attach your security device (1) tajima solution

1. Turn off the machine and unplug it for safety.
2. Locate the Angle Indicator Plate near the main shaft.
3. Align the plate correctly according to the machine's specifications.
4. Tighten any screws or fasteners securing the plate in place.
5. Ensure the plate is firmly attached and doesn't wobble.
6. Power on the machine and check if the plate remains in position during operation.
7. If needed, make further adjustments or seek professional assistance.

Question edited for clarity and typos.

Did you try replacing the motherboard battery.

https://www.google.com/search?q=Tajima+tmex-c901+error+3d6

and

https://www.google.com/search?q=Tajima+tmex-c901+software

..

Question edited for clarity.
Email address removed. You don't need our 11 million annual viewers to have it.
Question moved to Sewing Machines.

The maker has a contact form

Tajima group official site - Embroidery machine manufacturers

Tajima Embroidery Machine https://www.tajima.com This is the website of Tajima Group, the leading manufacturer of embroidery machines. Introduction of TAJIMA's multi-headed embroidery machines and ...

Check the Motherboard battery.

https://www.t-shirtforums.com/threads/reinstalling-firmware-on-a-tajima-tmex-c1201.576273/

Repeated here for C1501

http://www.digitsmith.com/tajima-tmex-c1501-software-75796.html

Video may help?

Error 12 on a Tajima TME-C612 embroidery machine typically indicates a problem with the machine's control panel or its communication with the machine's control board. To troubleshoot this issue, you should first check the connections between the control panel and the control board to ensure that they are properly connected and secure. If the connections appear to be fine, you may need to perform a firmware update on the machine to resolve the issue. The firmware update can be found on the Tajima website or you can contact Tajima support for assistance.
If the problem persists, it may be necessary to have a technician check the machine. The technician will be able to diagnose and repair the issue.
It is important to note that Error 12 can have multiple causes, and it is recommended to consult the machine manual or to contact the manufacturer support for specific troubleshooting steps.

If the color change motor on your Tajima embroidery machine is making noise but not moving, it could be due to a few different issues. Here are some troubleshooting steps you can try:

1. Check the connections: Make sure all the cables and connectors that attach to the color change motor are securely connected and not damaged.
2. Check for obstructions: Look for any obstructions that may be preventing the motor from moving freely. This could include thread or debris that has become tangled in the mechanism.
3. Lubricate the motor: If the motor is making noise, it could be due to lack of lubrication. Try adding a few drops of oil to the motor shaft to see if it helps.
4. Replace the motor: If none of the above steps work, it may be time to replace the color change motor. You can order a replacement part from Tajima or a Tajima dealer.

Note: If you're not comfortable with troubleshooting and repairing your embroidery machine, it's best to contact a professional technician for assistance.

http://www.tajima.com/productinfo/2014082711571877.html
follow this link see if it is what your looking for

I went google and typed in --workshop manual for tajima tmex c-1201 sewing machine -- and found many pages with pdf downloads for repair manuals and workshop manuals
do that and find the right site for you and down load the workshop manual and that may be a way of fixing your machine

Which model number.
Hirsch Support Tajima Embroidery

Error codes are listed here.
Tajima TME DC Electronics

how to remove error 3d7 for tajima tmfd machine

I have had a couple of Tajima units with what sounds like the same problem. I found the motor which drives the X axis had bad solder joints where the windings join the circuit board which the cable attaches to the motor. I resoldered the connections and they worked fine. If you don't have the soldering skills, or know someone who does, you may just need to replace the motor which is fairly expensive. It will probably take about 1 1/2 hours to take the motor assembly in and out, and about another hour to repair the solder joints.