Power Up - HP 8560A Service Manual

Power Up

See function block M of A6 Power Supply Schematic Diagram in the Component-Level
Information binder.
The Power Up circuitry generates the PWR UP signal, which tells the microprocessor that
the supplies are up and stable. PWR UP will go high when the +5 Vdc supply exceeds
+4.99 Vdc. PWR UP will go low when this voltage drops below t4.895 Vdc. Once PWR UP
is set low, it will stay low for at least 50 ms before going high, even if the +5 Vdc supply
exceeds i-4.99 Vdc before 50 ms have elapsed.
Display/Power Supply Section 12-17