402 Fault Finding of Control Head TM9100 Service Manual© Tait Electronics Limited August 200514.3 LCD Display FaultyThe LCD module is connected to the control-head board via the LCDconnector. The LCD module display is controlled by a serial data link to theFPGA. A faulty LCD display can be caused by the following:■ a loose or dirty LCD loom connection,■ a faulty LCD, or■ a fault on the control-head boardNote This section only deals with the display of the LCD. For faults ofthe LCD backlighting, refer to “LCD Backlighting Faulty” onpage 404.Note If some of the LCD pixels are faulty (usually complete rows orlines), send CCTM command 1006 1 to activate all LCD pixels.If some of the LCD pixels are faulty, replace the LCD.If the LCD display is faulty:1. Disconnect the LCD loom, visually inspect and clean the contacts,and reconnect the LCD loom. Visually inspect connector J102 foropen or shorted contacts.Figure 14.3 Circuit diagram of the LCD circuitry3V3LCD BACKLIGHT CTRLQ1023V3LCD HEATER CTRLQ102LCD RESETNLCD D/CLCD DATLCD SCLKLCD CENR4R5R6R7R8LCD RESETNLCD D/CLCD DATLCD SCLKLCD CENLED3V3HEATER123456789101112131416 15E108C102C103C101J102LCD ConnectorFPGAU601 LCD RESETN212
