Motorola T2260, Service Manual

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67 4/3/01
Troubleshooting
No LED Backlight
LED BL Regulator defect
Set the phone mode as a ‘Backlight Always On’ of ‘Backlight Select’ of ‘Display Options’ menu.
Verify the 2.8V BL Regulator Vout via U2400 pin 4 and BL control signal ‘High’ via U2400 pin 1
If the 2.8 Voltage BL Regulator Vout is failed with BL control signal ‘High’, replace the U2400
regulator IC.
Dim LED
If any dim LEDs are found out of 4 LCD LEDs and 8 keypad LEDs, measure Vf voltage of the
dim LEDs on the point of LED Anode (The typical Vf is 2.03 volt)
If the Vf is too high, replace the LED with good one.
No turn-On LED
If any dim LEDs are found out of 4 LCD LEDs and 8 keypad LEDs, replace the LEDs with good
ones.
Trouble Shooting(Power-up)
a) Battery either discharged or defective.
1. Measure battery voltage across a 50 ohm (>1 Watt)load.
2. If the battery voltage is <3.4 V DC, recharge the battery using the
appropriate battery charger.
3. If the battery will not recharge, replace the battery.
b) Battery mis-aligned.
1. Visually inspect the battery polarity
2. Check if two battery contact terminals of rear
housing are able to match battery contacts on board.
c) Shield defective
1. Check if carton tape is on power shield
2. Check if power shield can are short to battery contacts
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