Hi Robert
It sounds like the plug-it cable from the description above. Try using it for a full day with another cable and that will confirm it one way or another.
In my workshop I tend to use the same plug-it for every tool. The only problem that I have encountered is some slight damage to the outer insulation where I have scuffed the lead a few times. The business end is as good now as it was 3 years ago.
I use my RO90 quite a bit and every now and again I give it a good clean. I take off the sanding pad (as you would if you were about to put the delta pad on) and then use my vacuum nozzle and a piece of thin stick to get the clogged dust out from the inner region under the pad. This, I am sure, will have nothing to do with the problem that you have but is just good practice to improve air flow.
Peter