Guiness

This happened to me after the power cord was inadvertantly unplugged.  The machine ran normally on its internal battery for a while, and just before the battery was fully discharged, the tracing faded out.  Check your plug or the circuit the machine is plugged into.  If that's the case, feed it some electrucuty..

Thanks for the help.  Will try this tomorrow.  If no success, should I just replace the battery?

Just plug it in.  It will run with no usable rechargeable battery, but it won't run unplugged.  The rechargeable battery lets you use it during a house call or a power failure, but it is not essential.  Also, after you plug it in, if it was just the discharged battery, pressing reprint will print a copy of the last EKG you took while the printing failed.