compaq lte elite User Manual

							circuits:
o Main expansion base circuit (+/- 5 volts, +/- 12 volts)
o VBatt1 circuits (10 to 18.5 volts)
o VBatt2 circuits (10 to 18.5 volts)
The outputs to the above circuits are located on an edge card connector in
the power supply. The vertical circuit board plugs into this edge card
connector to distribute power to the unit.
Refer to Appendix A for pin assignments for the power supply output
connector.
Figure 6-9 illustrates the function of the power supply output circuits.
Main Expansion Base Circuit
The main expansion base circuit provides +/- 5 volts and +/- 12 volts to
the following:
o Internal drive bays
o Expansion board slots
o Integrated Ethernet and SCSI-2 circuitry
o All pass-through connectors 
						

							VBatt1 Circuits
The VBatt1 circuits provide 10 to 18.5 volts to the following:
o Computer (while docked)
o Docking mechanism
VBatt2 Circuits
The VBatt2 circuits provide 10 to 18.5 volts to the following:
o Battery charger in expansion base
o Voltage regulator on the expansion base system board, which converts 18.5
volts to 5 volts for the microcontroller, sensors, and wiring harness.
NOTE: The microcontroller controls the VBatt2 circuits.
Power-Up Sequencing
The VBatt1 and VBatt2 circuits power up whenever the expansion base is
connected to external power, whether the expansion base is on or off. This
allows a battery pack to be charged both in the computer and the expansion
base while power is off to the rest of the system.
The main expansion base circuits do not power up until the computer is
fully docked and the power switch is pressed. Once this happens, the
controller sends out a power-up signal to the main expansion base circuits
and a power-up signal to the docked computer.
NOTE: When a Compaq LTE Lite is docked in the expansion base, power for the
system can be turned on only with the expansion base power switch.
When a Compaq LTE Elite is docked in the expansion base, power can be
turned on with either the expansion base power switch or the computer
power switch.
Docking Mechanism 
						

							The expansion base has a motorized docking mechanism (Figure 6-10) that
docks and undocks the computer. The mechanism uses a sled apparatus; draw
hooks on the sled mate with notches in the bottom of the computer. The
mechanism does not operate if the unit is locked with a key or if a sensor
detects an undesirable condition such as an open PCMCIA door when a request
to undock is made.
If a computer cannot automatically undock from the expansion base due to a
malfunction or power failure, it can be manually undocked to override the
automatic docking mechanism.
Refer to Appendix D for procedures on automatic docking/undocking and
manual override undocking.
Computer Status Sensor 
						

							The expansion base has a two-part computer status sensor [1] (Figure 6-11)
on the docking mechanism sled. This sensor corresponds to two sense pads on
the bottom of the Compaq LTE Elite [2] or the bottom of a SmartStation
Adapter when connected to a Compaq LTE Lite. The computer status
sensor/sense pad combination indicates whether the computer is on, off, or
in Standby. The expansion base uses this information to determine if the
computer should be allowed to dock/undock. Refer to Appendix D for more
information on docking and undocking.
The computer status sensor is integrated into the docking mechanism. To
replace the computer status sensor, the docking mechanism must be replaced.
Vertical Circuit Board
The following connectors and switches are on the vertical circuit board
(Figure 6-12):
1. Drive power cable connector
2. IDE hard drive signal cable connector
3. Tape/diskette drive signal cable connector
4, 5. Two full-sized ISA expansion board slots 
						

							6. Edge card connection to the power supply
7. Edge card connector to the system board
8. Configuration switches for optional drives
In addition, the circuitry for the expansion base registers and hard drive
decode are on the vertical circuit board.
Configuration Switches
The configuration switches [8] (Figure 6-12) are accessible when the bottom
cover is removed. The configuration switch settings are listed on a label
on the bottom of the drive cage in drive position 1 (Figure 6-14). Refer to
Appendix C, Configuring the System for Optional Drives in the Compaq
SmartStation, for more information on setting the configuration switches.
ISA Expansion Board Cage
The expansion board cage [1] attaches to the vertical circuit board [2]
(Figure 6-13). The expansion board cage accepts two full-size Industry
Standard Architecture (ISA) 8-/16-bit expansion slots [3], [4]. The slots
line up with two vertical through hole card edge connectors [5], [6] on the
vertical circuit board. 
						

							IMPORTANT: Skirted expansion boards cannot be installed in the expansion
board connector that is next to the drive cable connectors [5]
(Figure 6-13).
Drive Cages/Drive Bays 
						

							The expansion base has two half-height drive cages for installing internal
drive options in the drive bays. The expansion base comes from the factory
with blank panels that cover the drive bay openings. The drive bays are
designated as drive positions 1 and 2 [1], [2] (Figure 6-14).
To be supported in the expansion base, drives must meet the power
requirements in Section 10.2, and the dimension requirements in Section
10.1.
Refer to Appendix C to configure the system for drives other than SCSI-2.
Refer to Appendix F to configure the system for SCSI-2 drives.
Drive Cables
The expansion base is shipped with one each of the following drive cables:
o Drive power
o IDE hard drive signal
o Tape/diskette drive signal
o Internal SCSI-2
For ease of identification, the vertical circuit board (also known as the 
						

							backplane board) and the system board (also known as the interconnect
board) each have a printed description of where the drive cables connect.
Each drive cable also has a printed description, a Compaq spare part
number, and a Compaq assembly part number. Refer to Section 9.15 for more
information on drive cable locations.
Power Switch Cable Harness
The power switch cable harness [7] (Figure 6-15) runs from the power switch
[8] to the harness extension cable on the system board [1] and includes the
following:
o Power switch and its soldered cable
o Cables for the computer status sensor
o Connectors for the PCMCIA card sensor (emitter and receiver)
o Power and hard drive LEDs (integrated into the power switch board)
Power Switch
The momentary type power switch [8] (Figure 6-15) provides power to the
main expansion base circuits if it is pressed after a computer is docked
(refer to Power Supply in this section).
The power switch is connected to the power switch cable harness and is
composed of the power switch board and small mechanical parts. The small
mechanical parts (button, spring, frame, and light pipes) can also be
replaced separately using parts from the Miscellaneous Small Mechanical
Parts Kit (Table 8-8).
NOTE: The power switch board is integrated into the power switch cable
harness. To replace the power switch board, the power switch cable
harness must be replaced (refer to Section 9.17).
Eject Switch Cable Harness
The eject switch cable harness [3] runs from the eject switch [4] to the
harness extension cable on the system board [1] (Figure 6-15) and includes
the following:
o Eject switch and its soldered cable
o Keylock switch and its soldered cable
o Battery charger LED (integrated into the eject switch board)
Eject Switch
The momentary type eject switch [4] (Figure 6-15) undocks the computer from
the expansion base after certain conditions are met (Appendix D).
The eject switch is connected to the eject switch cable harness and is
composed of the eject switch board and small mechanical parts. The small
mechanical parts (button, spring, frame, and light pipes) can also be 
						

							replaced separately using parts from the Miscellaneous Small Mechanical
Parts Kit (Table 8-8).
NOTE: The eject switch board is integrated into the eject switch cable
harness. To replace the eject switch board, the eject switch cable
harness must be replaced (Section 9.17).
Keylock Switch
The keylock switch [2] (Figure 6-15) is connected to the eject switch cable
harness. The keylock switch is actuated by the keylock assembly and is
closed when the keylock is in the locked position (refer to Keylock
Assembly and Override Blocker in this section). When the microcontroller
detects a closed keylock switch, it prevents power from being connected to
the docking mechanism, thus preventing the computer from docking or
undocking.
The keylock switch is integrated into the eject switch cable harness. To
replace the keylock switch, the eject switch cable harness must be
replaced.
PCMCIA Card Sensor (Emitter and Receiver)
The PCMCIA card sensor is a light curtain type, with two parts: an emitter
board [5] and a receiver board [6] (Figure 6-15). The card sensor detects
the presence of a PCMCIA card or card cable that extends beyond the safe
limits of the PCMCIA slot. When the sensor detects that the spring-loaded
PCMCIA door is open, it does not allow the computer to undock, thereby
preventing damage to the PCMCIA card and connector.
Refer to Appendix D for more information on undocking. 
						

							Keylock Assembly and Override Blocker
The keylock assembly [1] and override blocker [2], located in the bottom
cover, work together to provide system security (Figure 6-16).
The keylock assembly mechanically locks the bottom and top cover of the
expansion base together and closes the keylock switch. When closed, the
keylock switch electronically disables the docking mechanism (to prevent
unauthorized docking and undocking of the computer).
When locking the expansion base, the keylock assembly moves the override
blocker to cover the manual eject override slot [3] to prevent unauthorized
manual ejecting of the computer (Figure 6-16).