Tektronix H600 RFHawk, Service Manual

Page: 49 / 109

Theory of Operation
The power modes are:
Suspend mode . The platform automatically enters shutdown mode to save
battery power following a period of instrument inactivity, or when you press
the front panel power button. You can set the length of this inactivity from the
Start > Settings > Control Panel > Power Management > Power Saver
tab. Before entering this mode, registry information and nonvolatile memory
are backed up and all nonessential power supplies shut down. LCD backlights
are turned off and the touch-screen display is inactivated. The instrument
module will also be shut down.
During suspend mode, the real-time clock and SDRAM refresh remain active.
To return from this state, you must press the front-panel power switch to
power up the platform, which takes approximately one minute.
Display Power Saver mode . The front-panel status indicator changes from
Green to Amber to indicate the display Power Saver mode. In this state, the
display and backlight are turned off to save power. Instrument modules
remain powered on. Pressing the front-panel power switch cancels the Power
Saver mode and returns the platform to an active state. Measurements that are
running when you enter this mode continue to run.
Automatic Shutdown mode . If a voltage is present on fi ne-pitched
component pins under humid conditions, corrosion can occur over time.
Placing the internal circuitry in shutdown mode when not in use can minimize
this problem. If the platform remains in shutdown mode for more than two
hours, the processor system, with the exception of the real-time clock, is
completely powered off.
Transition to the power-down state occurs when the shutdown state timer
times-out or the internal batteries becomes critically low. Pressing the
front-panel power switch reactivates the internal circuitry and returns the
platform to an active state.
Internal Supplies to Module.
In addition to the power requirements of the internal
circuit boards, the platform provides the following voltages to the instrument
module.
Table 2-3: Platform voltage supplies to module
Characteristic Description
Voltages
+3.4 V DC ±0.14 V, 5 A at 17 W 1
–13 V DC ±0.5 V, 1 A at 13 W
+13 V DC ±0.5 V, 1 A at 13 W
Instrument Power Supply
Noise (peak-to-peak) for
1 Megahertz bandwidth < 250 mV for ±13 V
< 100 mV for +3.4 V
H600 & SA2600 Service Manual 2–7