USB Y Cable (MM->F) - How exactly do they work? Can I use a charger?

[canadianvice]

So, I have a tablet that I'm using as an additional screen, but it does not seem to be able to pull sufficient current from the USB 3 port it is plugged into to remain on. Could be the tab, it's kind of bad and its battery has certainly seen better days, but I'm hoping to make use of it as it's far easier to mount than a regular screen in that position.

Anyhow, my idea as a solution to this problem was a cable such as this one:
here

I can't find the MM-F version I found the other day, but I'm mostly concerned about the principle and this is basically the same idea.

Now, on to my question - is it possible (and not dangerous to the mobo) for me to feed the subsidiary with wall-charger power (probably a 2A charger) and then keep the data plugged in? I'm thinking I would probably cut the ground/volt line on the main-usb, to avoid any issues with feedthrough? Is this necessary?

 

[Alabalcho]

What's the exact model of your tablet?

 

[canadianvice]

What's the exact model of your tablet?

It's an ASUS TF103C, also known as a K010. Not sure what bearing that has though. Please keep in mind I'm not troubleshooting the tablet here - I'm well aware it's a piece of crap and has been mistreated. I'm interested in making sure that if I hook something up in this manner, the current is not going to feed into my PC motherboard and cause trouble there.

I've been using it with success as an additional display, it's just that it doesn't get enough current to stay on into perpetuity while running this, so clearly I need something more powerful than the standard PC usb port. Oh, and to avoid the obvious suggestion, I need it connected to the PC for data because it the monitor app runs off of ADB, and all wifi options I've found have proven too slow to be usable.

 

[Alabalcho]

So, if I get you correctly: YOu need a cable with one end of the fork going into a PC (for USB data only), other end of the fork into a power adapter, and base of the cable into the tablet?

What are the specs original power adapter for that tablet?

 

[canadianvice]

I have so many bricks at this point I have no clue which was the original, but I've got an ASUS oem brick I'd probably use that's specc'd to 5V2A. It's not quick charge or anything, just one of those higher current offerings which is relatively unoffensive to any device I'd use it with.

I'm probably just going to cut the 5V line from the isolated part of the USB 3, which should render the question moot, but I'm interested to see what others suggest.

For the record, I found the exact cable I was looking at the other day: here. Unlike the other one this has the advantage of a clear separation between the USB 3 end and the USB 2, so if I want to cut the 5v+- line from the USB 3 it should not be prohibitively hard.

 

[canadianvice]

Update: Got the cable, did some small tests.

Per my suspicion, if the item it connects cannot consistently use the amperage being pumped through, you can get some feedback. Simple solution: Cut the Red 5v+- wire on the part you don't need.

I now have my tablet wired to a USB 3.0 data for the ADB on my Desktop, and then the subsidiary USB 2 portion is feeding from a 2.1A wall charger. No feed through. The battery on this thing seems to be in poor condition though, as it doesn't maintain enough power at idle, but at least it charges overnight now.