Does the 7500 series still use batteries? The older machines did, and you were supposed to change the batteries (AA)
yearly. This was a common problem years ago. Dealers didn't tell you to change batteries, and now if you buy one of these machines used with no manual, you have no way of knowing. Look at the underside of the machine - if there is a compartment that says open - you need batteries. It was grouped with the 1400 series which DID need batteries.