[drakerjd]

I own a Proform ERS 10.0 treadmill, serial # E51277572, about 19 years old now and still kicking until recently. Got the dreaded EEE on console at startup. Belt would run for a few seconds before error came on. Researched, determined either dirty optic disk or motor control board. Replaced MC board before and it fixed problem (about 2 years ago). Replaced board again, figuring I had not properly lubed the deck and taxed the control board to the point it fail, again. No luck with new MC board, same problem with EEE showing on console after short start-up of belt. Looked at optic disk more closely, noting that the RPM sensor itself was broken. Replaced the sensor. Also I noted that the RPM disk on this particular treadmill is attached to the front roller hub, and is oblong at inside center hole to conform to the shape of the roller hub. Also the RPM disk appears to have half circles, and a smaller outside diameter than any replacement disk I've researched. It does not appear that the sensor sides (two) would have even beamed across the disk to provide an RPM readout back to the controller moter board. The half circles are at the outside edge of the disk, and are not jagged edged, or otherwise scored to indicate any wear damage that might have reduced the original diameter down to what's left, the half circles. So my question is does anyone know for a fact whether there were two distinctly shaped disks used on early models of this treadmill, one off the front roller (right side if facing the console from running position on deck), and the other off the incline motor, that one having the fully shaped holes, and the smaller, center hole? I could try to drill, and file down the interior of the disk I bought to replace the one attached to the roller with, as the replacement disk sold to me is exactly like the one on the incline motor. That would at least tell me if the original disk was in fact fully sized, with complete holes fully readable by the sensor. Incidentally, I'm replacing the RPM disk, half circled, because it appears warped, and I thought that may be factoring into problems for sensor reading. Seems like a lot to do just to keep an old treadmill running, but I hate to give up on repair investment to date. I'm hoping this makes sense to somebody.....thanks!