LG 50PQ30 Training Manual page 76

Y - Drive Buffer Troubleshooting
Y - Drive Buffer Troubleshooting
YOU CAN CHECK ALL 8 BUFFER ICs USING THIS PROCEDURE
YOU CAN CHECK ALL 8 BUFFER ICs USING THIS PROCEDURE
BACK SIDE OF Y-DRIVE BOARD
BUFFER IC FLOATING GROUND (FGnd)
128
Output
Pins
42
• Any of these output lugs can be tested.
• Look for shorts indicating a defective Buffer IC
BUFFER IC FGnd
Indicated by white outline
BLACK LEAD ON
BUFFER IC FGnd
Indicated by white outline
43 43
Using the "Diode Test" on the DVM, check
the pins for shorts or abnormal loads.
RED LEAD ON
128 Output Pins per/FPC (Flexible Printed Circuit)
6 Ribbon cables (Horizontal Electrodes)
768 Total Horizontal Electrodes controlling Vertical resolution
76
BLACK LEAD ON "ANY"
OUTPUT LUG.
READING 0.798 V
RED LEAD ON "ANY"
OUTPUT LUG.
READING "OPEN"
November 2009 50PQ30 Plasma