Akai LM-H30CJSA, Руководство по обслуживанию

Страница: 33 / 64

9.3 Key
、
LED&IR Board Circuit
Refer to Key
、
LED & IR circuit diagram of PWB-0565 in Chapter10.2 and sheet 5
of PWB-0663 circuit diagram(Main Board).
* Key : The Keyboard is connected with Main Board through socket P021 and wire
P021A and to control the I012 (MCU) .So , if the operation of key is fail , the I012
(MCU) may fail .
* IR : The IR01 (PL-IRM0101-3) is a receiver for infrared remote control systems.
The demodulated output signal can directly be decoded by MCU I012 #15 through
P015 #6 and wire P015A .
* LED :The dual LED D601 on LED&IR Board is controlled by MCU I012 #24
、
# 25
through P015 #2
、
#3 and wire P015A.
9.4 Inverter Board Circuit
The Inverter Board is fed with +24V through socket P802 #1~5 on PB01 (Power
Module:PWB-0656 )and wire P802A .It offers 4.5mA (typical ) to each lamp of
backlight in LCD panel. (30” panel :16Lamps , 27” panel :14 Lamps)
The On / Off of the inverter is controlled by the voltage of P802 # 11 which is
applied from I019 (S c aler:TP6760) #95 (FPBACK) via P019 #1 on Main Board.
While the voltage of P802 #11 is ‘H’ (2~3.3V) , the lamp of backlight will be turned
on. While the voltage of P802 # 11 is ‘L’ (0~ 0.8V) , the lamp of backlight will be
turned off.
Adjusting the Brightness in OSD menu is to control the voltage at #62 (DVD0) of
I019 (Scaler:TP6760) and then applies to P019 #2 on Main Board and P802 #12 to
Inverter . The range of the voltage is from 0V to 2.7V. If the voltage of P802 #12 is
0V, the screen will get light ; if it’s 2.7V, the screen will get dim. It means that the
different voltage will change the lamp current through the inverter to make the screen
lighter or dimmer.
- 31 -