Faultfinding Guide
GB 58 CDR7798.
8.1.3 Display board troubleshooting guide
Figure 8-9 ‘Display board troubleshooting’
SWITCH POWER ON,
EXIT STAND BY
MODE
DISPLAY BOARD
OK
DISPLAY?
CHECK :
• SUPPLY VOLTAGES
⇒ -38V ±5% at conn. 1119-2
⇒ 3V8 ± 10% between conn. 1119-1 and 1119-3
⇒ +5V ± 5 % at conn. 1119-10 (1121-4 for CDR570/930)
• CLOCK SIGNAL
⇒ 8Mhz at pins 8, 9 of IC7104
• CONTROL SIGNALS
⇒ RESETN 3V3 (high) at conn.1119-4 after start up
⇒ I2C DATA at conn. 1119-5
⇒ I2C CLK at conn. 1119-7 (1121-1 for CDR570/930)
• FTD DRIVE LINES
⇒ Filament voltage 3V8 ± 10% between pins 1-2-3 and
pins 45-46-47 (pins 1-2 and pins 48-49 for CDR
570/930) of the FTD (1113)
⇒ Grid lines (see test instructions)
⇒ Segment lines (see test instructions)
• ELECTRICAL SERVICE DIAGNOSTICS - Local display test
YES
YES
YES
KEY
FUNCTIONS?
REMOTE
CONTROL?
NO
NO
CHECK:
• KEY MATRIX LINES (see test instructions)
• ELECTRICAL SERVICE DIAGNOSTICS – Keyboard test
• EASY JOG KNOB (see test instructions)
NO
CHECK:
• IR RECEIVER signal at pin 22 of IC7104 (see test instructions)
• ELECTRICAL SERVICE DIAGNOSTICS – Remote control test
CL 96532076_020.eps
290799
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