How do I take the battery out of an Emerson 756

DON'T cut lumps out of your machine. There will be a sequence you use to remove the parts you need to access to the gears more easily. The Youtuber you referred to sounds like they have zero knowledge when it comes to these older style machines.
'Note' Some of the gear mount nuts are on a "Reverse" thread meaning you turn them the 'wrong' way to get them off.
My limited knowledge is more on the much older hand crank and treadle machines.
Try the Youtube link below for a channel called 'Andy Tube'. He has a good reputation for correct repair methods. The link is for a 758 but they're both Touch and Sew machines.
You could also try the Facebook group 'Vintage Singer Sewing Machines' as they have loads of knowledge about loads of different machines.
https://www.youtube.com/watch?v=zxd5hKjGBlE

You can find your solution here :
How to Set the Default Download Location to an SD Card

Hi John:
Click opn this link
https://www.google.ca/search?q=John+Deere+755+service+manual&rlz=1C1GGGE_enCA468&oq=John+Deere+755+service+manual&aqs=chrome..69i57j0l5.888j0j8&sourceid=chrome&ie=UTF-8

sounds like internet connection, check your internet settings, and possibly reboot your wifi router

I t is behind teardrop shaped cover below r ight hand brake drum.

I haven't worked on Paxar products, but the manual directions seem reasonably complete, with drawings. (PDF pages 17-22 provide the basic directions; the following pages give directions for special media types and options.)


Error #756 = "Load Supplies"

I deduce from this that somehow you missed the paper detector when you loaded the supply strip. This is probably the "die cut sensor" referenced on page 2.3 (PDF page 19, shown in drawing on the next page). Make sure the strip feeds through the detector slot.

Are you sure it's not a 756 error? 756 is a supply error, basically saying that you ave no supplies loaded. A 956 is an unspecific generic error code, saying you have a mother board failure.
The display on the 9820 is difficult to read. I'd say you have a 756 error.
Double check your dip switch settings and make sure they match the type of supplies you have loaded.

The CA 756 doesn't really have any matrix capabilities. If you're looking for a keystroke method for inverting a matrix or finding its determinant, for example, this calculator won't do it. The closest the CA 756 comes is allowing you to use a series of memory registers as a vector (one-dimensional array).

That probably wasn't the answer you wanted to see, but there it is.

Follow this link; http://asia.optoma.com/Product_User_Menu/EP757UserManualEn.pdf Gives the manual for the EzPro 757 which may help you out. There do appear to be quite a few similarities and differences between the models, but unfortunately if a manual is available online for the 756 then i couldnt find it. Hope it helps at least a bit :)