Abstract: A magnetic reading head is provided in a tray acceptor for determining the presence of magnetic characteristics in a paper tendered as a valid currency or note. Fundamentally, the invention comprises a spring assembly, receiving a magnetic reading head, which is adjustable to position the reading head in sensing engagement with the paper maintained in the tray and offered for validation. The magnetic reading head provides a series of pulses corresponding to the presence of magnetic characteristics in the paper to a capacitor which charges upon the receipt of each pulse. When the tray reaches a set position, the charge on the capacitor is sensed, and a determination is made as to whether the paper has sufficient magnetic characteristics to constitute a valid note or currency. A time delay circuit is provided such that the magnetic sensing function can be performed only once during a preset time period.