I am told my Elna 7000 motherboard is beyond repair and I will have to replace machine as it is not worth replacing motherboard. Can this be true ?

You may have to do some research. There are some computer-handy people who are able to repair computer boards. It's worth a try before pouring money into a new machine. Sometimes you can find a donor machine with a good board but other issues.

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You might check with another sewing machine shop and see what they tell you, you would have to consider the cost of replacing the motherboard and the price of a new machine