Troubleshooting Procedures - Motorola V200 Service Manual

Troubleshooting

Troubleshooting Procedures

64
The goal in troubleshooting is to quickly narrow down the possibilities to isolate a
failure to a single faulty component. This is especially important before deciding to
replace a multi-pin IC, filter, or other component that is difficult or risky to replace.
Sometimes the problem will be visually obvious; such as a cold solder joint, cracked
chip, or tombstone. At other times, it will be necessary to measure a voltage. Board-
level repair requires the equipment specified in Table 2.
No Turn-On
1. Turn on failed.
2. Visually check for damaged parts.
3. Check for shorts.
• Apply 4.4V with 1A current limiting to CE bus connector J1000 pin 3.
• If the UUT draws more than 0.5A, check all U1200 regulators. Make
sure they are not shorted to ground.
• If problem still exists, go to step 4.
4. Switch R9972 to R9952 to force WDG high.
5. Check for the power route for U1200 B+.
• If B+ is present, go to step 6.
• If problem still exists, check VR1202 pin 1.
• If there isn't 4.4V on VR1202 pin 1, check J1000 and make sure it is
placed correctly.
• If there isn't a 4.4V on CR1050 pin 2, replace Q1305 or reflow U1200 if
needed.
• If problem still exists, check CR1050 and Q1306. Make sure they are
placed correctly.
6. Check U1200 regulator output voltages.
• If the voltages on the following regulators are correct, go to step 7.
• ANALOG_1.8V = 1.875V
• DIGITAL_1.8V = 1.875V
• MEMORY_VCC = 1.875V
• LOGIC_2.75V = 2.775V
• V4 = 2.775V
• RX_2.75V = 2.775V
• If problem still exists, reflow U1200, or replace U1200 if reflow does not
work.
7. Check the RTC clock from U1200.
• If there is a 32.768 KHz clock on U326 pin 2, go to step 8.
• If there is no clock on U326 pin 2, reflow U1200.
• If problem still exists (the phone's internal clock is running at
32.768 kHz +/- 50%), check the RTC crystal Y1170
• If there is no 32 KHz sine wave on Y1170, check C1171 and C1172,
make sure they are placed correctly before replacing Y1170.
• If problem still exists, go to step 8.
8. Check the 16.8 MHz clock going into U1100 pin M1.
• If there is a 16.8 MHz clock at C1173, go to step 9.
• If problem still exists, make sure the voltage on Q325 pin 2 and pin 3
are both 2.75V.
9. Flash EEPORM troubleshooting.
• If the Flash_CS is toggling, go to step 10.
• If problem still exists, reflow flash U1300, or replace U1300 if reflow
October 04, 2001
CDMA V200
6881039B10