The Nbp Board; The Inverter Board; The Display - Philips TeleMon B M2636B Service Manual

Hardware
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The NBP
The Non-invasive Blood Pressure (NBP) Board (Figure 5-9 on page 5-38) performs
Board
operations relating to taking a blood pressure with the cuff. The NBP Board contains:
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The Inverter
The Inverter Board (Figure 5-10 on page 5-39) applies 380 VAC at 5 mA to the LCD's
Board
backlight, which is fluorescent. An oscillator in the inverter circuit changes DC input current
from either the 10.8 battery or the external power supply to AC.
The Inverter Board Assembly consists of:
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The Display

The Display (Figure 5-13 on page 5-41) contains:
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2-2 Hardware and Software Description
– When OFF, applies line power to the battery for charging if the External Power
Supply is connected. Only the various power and battery indicators are functional.
– When OFF, shuts off all power if the External Power Supply is not connected. The
coin battery on the Main Board continues to drive the Real Time (RT) clock and
some memory circuits.
The External Power Connector, which extends through an opening in the rear housing.
Use of this connector feeds power from the External Power Supply to the Main Board,
which may also distribute it to other modules.
Serial Port. The Serial Port Connector on the Main Board is accessed through an
opening at the bottom of the Rear Housing. The port is used for software updates. The
opening is covered by a snap-lock door.
Optical devices. The transmitter communicates with the TeleMon, when docked,
through an infrared (IR) path. IR data is reflected onto an optical device on the Main
Board through a perforation in the IR Shield. Another device provides a control and
data path to the transmitter through a second perforation.
IC's for regulating the operation of the Air Pump.
A connector for the NBP-to-Main Cable.
The Air Pump with mounting device. The pump is specified for at least 30,000 cycles
before it needs to be replaced; 10,000 cycles before it needs to be calibrated.
Conduit tubing for the air.
A metal shield to limit radiation from the inverter circuits.

The Inverter Board.

Integral connectors for the Inverter-to-Main and Inverter-to-Display Cables.
LCD. The LCD has a half-life of approximately two years. It should be replaced when
it loses its brightness.
Back Light.
Non-detachable Inverter-to-Display power cable.