KitchenAid KBMS1454R 1000 Watts Microwave Oven

Question

for the last year or so the display crystals would come and go.today the right side of panel quit.if i tab cook time to over 90 min.and hit start it will work.no display code .there are a row of small triangels on top 775 in the display ,a couple of more triangle on the bottom.when i depress the start ,cancle ,add a minuite.basicly from the k**b to right the triangle go out.so it seem it is the membrane and the display?