Service manual

4. BOARD/UNIT DESCRIPTION
Service Manual BSM-4100 4.17
The power supply block consists of the power supply unit (+15 V DC output), heat
sink chassis, fuse holder built-in type AC inlet socket, ground terminal and line
frequency detection coil. Refer to Section 8 REPLACEABLE PARTS LIST.
This power supply unit same as in the BSM-1101/1102, BSM-2301 and WEP-
4204/4208 is used.
Power Supply Block
12.1 inch TFT color LCD which has 800 dots × 600 dots (SVGA) is used as the
display. This LCD unit can display maximum 512 colors. 12 colors can be
assigned for waveforms and each vital sign parameter by the user.
Since the LCD unit is covered with a polarization filter which is weak against
impact and pressure, it requires your attention during service.
The LCD unit has two cold cathode tubes to backlight the LCD. The high voltage
for the two tubes is supplied from the inverter board.
It takes approx. 25,000 hours (about 2 years and 10 months) or 50,000 hours
(about 5 years and 9 months for the monitors with the revision number CA or later)
for the brightness to decrease from maximum to half brightness (lifetime of the
backlight) if the two tubes at the maximum brightness work in continuous
operation. Therefore, the tube may need to be replaced after 25,000 hours or
50,000 hours (for monitors with the revision number CA or later) of use.
LCD Unit