Sharp GX20 Service Manual - Page 63

Main display does not function.

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11. Main display does not function. CONFIDENTIAL GX20 Is main display to CN404 surely inserted? NO Connector insertion defective. YES Clean the connector CN404 contact point and insert the main display again. Does it function? YES Does the display function after replacement? NO Connector insertion part soiled. YES Main display defective. NO More than 3.6 V output at VBAT_S terminal (IC202 4 pin), VBAT_AP terminal (FS402 to FS401) and VBAT_BB terminal (IC202 22 pin)? YES Voltage of 2.8 V ± 0.1 V applied to TP209? YES More than 3.0 V ± 0.1 V applied to TP213? YES More than 1.8 V ± 0.1 V applied to TP218? NO Refer to Troubleshooting, "Power does not turn on." (see page 2-42). NO Refer to Troubleshooting, "Power does not turn on." (see page 2-42). NO Refer to Troubleshooting, "Power does not turn on." (see page 2-42). NO Regulator IC207 or jumper (TP218 to IC207 5 pin) defective. YES 13 MHz output at clock TP414? YES 3.0 V ± 0.1 V output at LCD_RST (TP404)? Are appearance and mounting of C417, C473 and R413 properly given? YES Voltage of 3.0 V ± 0.1 V applied to CN404 34 pin, 37 pin and 38 pin? Are appearance and mounting of jumper (CN404 34 pin to VINT line), jumper (CN404 37 pin to VINT line), C447 and C453 properly given? YES 3.0 V ± 0.1 V output at the liquid crystal reset (CN404 33 pin and C470)? Are appearance and mounting of C470 properly given? YES Approx. 62 Hz of signal given to TP426? Proper appearance and mounting given to C469, C471, C472, and C474? YES Normal voltage applied to the following terminal? TP430: Approx. 10 V Or are appearance and mounting of C450, C451, C452, C454, C455, C457, C458, C459, C460, C461 and Jumper (CN404 49 pin to 51 pin) properly given? YES Main display defective. Or defective mounting of connector CN404. NO Refer to Troubleshooting, "Power does not turn on." (see page 2-42). NO IC104 Defective. Defective mounting of C417, C473 and R413. NO CN404, jumper (CN404 34 pin to VINT line), jumper (CN404 37 pin to VINT line), C447 and C453 defective or defective mounting. NO Display controller (IC403) and C470 defective or defective mounting. NO Display controller (IC403), C469, C471, C472 and C474 defective or defective mounting. NO Main display, CN404, C450, C451, C452, C454, C455, C457, C458, C459, C460, C461 and Jumper (CN404 49 pin to 51 pin) defective. 2 - 57

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GX20
2 – 57
CONFIDENTIAL
11. Main display does not function.
Is main display to CN404 surely inserted?
Connector insertion defective.
Clean the connector CN404 contact point and insert the main
display again. Does it function?
Connector insertion part soiled.
Does the display function after replacement?
Main display defective.
More than 3.6 V output at VBAT_S terminal (IC202 4 pin),
VBAT_AP terminal (FS402 to FS401) and VBAT_BB terminal
(IC202 22 pin)?
Refer to Troubleshooting, "Power does not turn on."
(see page 2-42).
Voltage of 2.8 V
±
0.1 V applied to TP209?
Refer to Troubleshooting, “Power does not turn on.”
(see page 2-42).
More than 3.0 V
±
0.1 V applied to TP213?
Refer to Troubleshooting, “Power does not turn on.”
(see page 2-42).
More than 1.8 V
±
0.1 V applied to TP218?
Regulator IC207 or jumper (TP218 to IC207 5 pin) defective.
13 MHz output at clock TP414?
Refer to Troubleshooting, “Power does not turn on.”
(see page 2-42).
3.0 V
±
0.1 V output at LCD_RST (TP404)?
Are appearance and mounting of C417, C473 and R413 prop-
erly given?
IC104 Defective.
Defective mounting of C417, C473 and R413.
Voltage of 3.0 V
±
0.1 V applied to CN404 34 pin, 37 pin and
38 pin?
Are appearance and mounting of jumper (CN404 34 pin to
VINT line), jumper (CN404 37 pin to VINT line), C447 and
C453 properly given?
CN404, jumper (CN404 34 pin to VINT line), jumper (CN404
37 pin to VINT line), C447 and C453 defective or defective
mounting.
3.0 V
±
0.1 V output at the liquid crystal reset (CN404 33 pin
and C470)?
Are appearance and mounting of C470 properly given?
Display controller (IC403) and C470 defective or defective
mounting.
Approx. 62 Hz of signal given to TP426?
Proper appearance and mounting given to C469, C471, C472,
and C474?
Display controller (IC403), C469, C471, C472 and C474
defective or defective mounting.
Normal voltage applied to the following terminal?
TP430: Approx. 10 V
Or are appearance and mounting of C450, C451, C452,
C454, C455, C457, C458, C459, C460, C461 and Jumper
(CN404 49 pin to 51 pin) properly given?
Main display, CN404, C450, C451, C452, C454, C455, C457,
C458, C459, C460, C461 and Jumper (CN404 49 pin to 51
pin) defective.
Main display defective.
Or defective mounting of connector CN404.
NO
YES
NO
YES
YES
NO
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES