LG 50PS80 Series, Руководство по обучению

Страница: 43 / 139

43
August 2009 Plasma 50PS80
Power Supply Basic Operation Power Supply Basic Operation
AC Voltage is supplied to the SMPS Board at Connector SC101 from the AC Input assembly. Standby 5V is developed from
165V source supply (which during run measures 380V measured from the primary fuse F302).
This supply is also used to generate all other voltages on the SMPS.
The STBY5V (standby) is B+ for the Sub Micon (IC701) on the SMPS and output at P814 pins 11 and 23 then sent to the
Main PWB for Microprocessor (IC1) operation. AC Detect is generated on the SMPS, by rectifying a small sample of the
A/C Line at D102 and associated circuitry and routed to the Sub Micon (IC701) where it outputs at pin 15 and sent to P814
pin 18 to the Main Board where it is sensed and monitored by the Main Microprocessor (IC1106). If AC Det is missing the
set will not work. The Main Board will be held in Reset until AC Det returns.
A new feature included on the side keypad is called a Power Button which opens a ground allowing the “Key On” line of
P814 Pin 24 to go high, turning off the 5V STB line defeating the Micro Processor (IC1106) on the Main Board and Remote
Control Operation.
When the Microprocessor (IC1106) on the Main Board receives an “ ON “ Command from either the Power button or the
Remote IR Signal, it outputs a high called RL ON at Pin 19 of P814. This command causes the Relay Drive Circuit to
close both Relays RL102 and RL103 bringing the PFC source up to full power by increasing the 165V standby to 380V
run which can be read measuring voltage at Fuse F302 and F801 from “Hot” Ground. At this time the run voltages 12V,
and +5V sources become active and are sent to the Main Board via P814 (12V at pins 5 and 6 and 5V at pins 9,10, and
12). The 5V detect line from the Main Board to the SMPS Board can be measured at pin 17 of P814. It is not used.
The next step is for the Microprocessor (IC1106) on the Main Board to output a high on M5V ON Line to the SMPS at P814
Pin 21 which is sensed by the Sub Micon (IC701) turning on the M5V line and output at P811 and P812 pins 9 and 10 to
the Y and Z SUS boards and P813 pins 1~4 to the Control board.
Full Power occurs when the Microprocessor (IC1106) on the Main Board brings the VS-ON line high at Pin 20 of P814 of
the SMPS Board. VS-ON is routed to the Sub Micon (IC701) which turns on the 17V Audio, VA, and the VS supplies. VA
and VS output at P811 to the Y-SUS board and P812 to the Z-SUS board. (VA pins 6 and 7 and VS pins 1 and 2 of either
connector) the 17V Audio supply outputs to the Main board at P814 pins 1 and 2.
AUTO GND Pin 22 of P814: This pin is grounded on the Main board. When it is grounded, the Sub Micon IC701 works in
the normal mode. Meaning it turns on the power supply via commands sent from the Main board. When this pin is floated
(opened), it pulls up and turns the Sub Micon IC701 on in the Auto mode. In this state, the Sub Micon turns on the power
supply in stages automatically. A load is necessary to regulate the 17V with the SMPS disconnected. This is a good test if
the Main board is suspect.