I just bought and installed a typical inexpensive plastic case and gear replacement quartz clock movement and installed it in a clock. It runs one second slow per day and I want better accuracy than that. Does anyone have a method to adjust a supposedly unadjustable quartz clock movement or is it possible to modify a quartz clock movement by wiring in a small adjustable potentiometer or a variable resistor? If neither is possible, does anyone have a source for an accurate quartz clock movement? I would be satisfied with + - one second per week or better.