Lcd unreadable lcd screen has been going dark for a while, but now is unreadable. can i buy and replace with new lcd myself?

Hi, It is very unlikely that you will be able to get the LCD screen as a replacement part. Contact Brother for the nearest service center.
Getting parts directly from the manufacturer is nearly impossible.
Bob

the touch screen and computer both need to be checked

Try this link for an affordable solution to repairing your Janome MC 8000 Display Back Light.

https://sew-bright.com/products/janome-memory-craft-8000-lcd-backlight-replacement-kit

When your BabyLock Esante ESi2 is otherwise working fine but the LCD display screen begins to grow darker and you find you just can't read it, the only thing you can do is replace the BabyLock Esante ESi2 LCD screen, or buy a new machine. BabyLock no longer stock this item direct, but there is an affordable replacement available....Check this Link

When your Brother PC 7500 is otherwise working fine but the LCD display screen begins to grow darker and you find you just can't read it, the only thing you can do is replace the Brother PC 7500 LCD screen, or buy a new machine.Brother no longer stock this item direct, but there is an affordable replacement available.
Check this Link

There is an LCD Backlight Panel that illuminates the screen, and yes, they do fail.
Before you start, just check the screen contrast dial inside the top cover, front right, they can be easily knocked and this will also cause the screen to go light or dark.
Janome no longer supplies the LCD Backlight, however, we have an after market replacement at our store, and also provide fitting instructions and a good deal more besides.
If you care to contact me I can send a Diagnostic Routine and the Screen Reset instructions for you to check if there is anything else causing troubles.
Please remember to give details of your dilemma as we do receive a lot of requests.
Contact Link
Cheers
Martyn

Have you checked the dealer locator at the Babylock website?

Another option would be a Brother dealer as the machines are from the same "family".

The LCD Backlight is prone to going dark eventually and fails progressively, but you can buy a replacement and even instal it yourself.....
We can now supply the LCD Backlight Screen for the Janome Memory Craft MC 8000 and Memory Craft MC 5700. 
Keep your old Janome, save money and reduce unnecessary landfill.
It also comes with comprehensive installation instructions from the Original Janome Service Manual which are sent in advance so you can look at the "How to do it" before you decide whether you wish to DIY or enlist the services of a trusted friend or take the LCD Screen and installation instructions to your friendly local technician and have them do it for you.
Here is the LCD Backlight Link

We have the Janome MC8000 touch screen avaliable please contact us from our website www.sewingmachine.com.au

We have about 30 electroluminescent backlights for the 8000 still available .These are not original Janome parts. You will need a Janome service person to install then for you as it requires taking apart alot of the machine to get to the display. We can provide instructions if this person is unsure how to fit. Once the display is out, the process is simple. They are AUD$60 each including shipping. Email at [email protected]