LG Plasma Y Drive

Y DRIVE BOARD TROUBLESHOOTING - LG PLASMA TV 50PG20

Y-DRIVE BOARD

Y-Drive Board works as a path supplying the Sustain and
Reset waveforms, which are made in the Y-SUSTAIN B/D and sent to the Panel
through SCAN DRIVER IC’s.  The Y Drive
Boards supply a waveform, which selects the horizontal electrodes sequentially.

50PG20 uses 8 DRIVER ICs on 2 Boards (TOP, BOTTOM: 4 each).  50G1 Panel has 768 Vertical lines of
resolution (Horizontal Grids determine V Resolution)

4 Ribbons (Tabs) separated into 2 = 192 grids per tab.

8 Ribbon inputs to 4 Tabs = 96 lines per ribbon input

2 Buffers per Ribbon input = 96 lines per ribbon input.

5 Volts (Floating Ground) 5VFG and Logic Signals from Y-SUS
Board are supplied to the Top Drive Board on Connector P100.

5 Volts (Floating Ground) 5VFGinput also enters the Bottom Y
Drive Board at P200.

CLICK ON THE PICTURES TO ZOOM IN

To remove the Ribbon Cable from the connector first
carefully lift the Locking Tab from the back and tilt it forward (lift from the
outside edge as shown).

Lift up the entire Ribbon Cable gently to release the Tabs
on each end.  Gently slide the Ribbon
Cable free from the connector.

To re-install the Ribbon Cable carefully slide it back into
the slot, be sure the Tab is seated securely and press the Locking Tab back to
the locked position.

The Ribbon Cable is clearly improperly seated into the
connector. You can tell by observing the linearity.  Note the cable is
crooked. In this case the Tab on the Ribbon cable was improperly seated
at the bottom. This can
cause bars, lines, and intermittent lines abnormalities in the picture.
Remove the ribbon cable and re-seat it correctly.

Y Drive Upper Troubleshooting

Using the “Diode Test” on the DVM, check the pins for shorts
or abnormal loads.

Using the “Diode Test” on the DVM, check the pins for shorts
or abnormal loads.

Y Drive Lower Troubleshooting.

Using the “Diode Test” on the DVM, check the pins for shorts
or abnormal loads.

YOU CAN CHECK ALL 8 BUFFER ICs USING THIS
PROCEDURE