Trouble Shooting; Fault Diagnosis Of The Bga (Ball Grid Array) Ic - Kenwood TS-990S Service Manual

TS-990S

Fault Diagnosis of the BGA (Ball Grid Array) IC

■ Overview
This fl ow chart will determine whether the BGA parts are faulty when the transceiver does not start normally, or the LCD
screen is blurry or has an unusual coloring.
■ BGA parts
Application MCU (IC1, IC201), DDR2 (IC2, IC3, IC202, IC203)
When the BGA IC is problematic, please bring the printed circuit board (X46-3390-01) in for service.
● Checking power supply voltage
Checking voltage
Points to be checked Normal voltage
1.8V_1: L1 or L201 1.8V
3.3V_2: F1 3.3V (Check whether F1 is problematic.)
1.2V_3: L2 or L202
1.2V
1.8V (Check whether F801 (DC-DC unit C/3)
1.8V_4: CN2 (1 pin)
is problematic.)
3.3V_5: F2 3.3V (Check whether F2 is problematic.)
Power supply of each device is connected through the fuse or coil.
[MCU: IC1]
1.8V_1: L1, 3.3V_2: F1, 1.2V_3: L2
1.8V_4: F801 (DC-DC unit C/3), 3.3V_5: F2
[MCU: IC201]
1.8V_1: L201, 3.3V_2: F1, 1.2V_3: L202
1.8V_4: F801 (DC-DC unit C/3), 3.3V_5: F2
[DDR2: IC2, IC3]
1.8V_1: L1
[DDR2: IC202, IC203]
1.8V_1: L201
● Checking the clock
Checking the SYS clock
Points to be checked
26.000MHz MCU (IC1) side R95
MCU (IC201) side R303
Checking the SYS_32k clock
Points to be checked
32.768kHz MCU (IC1) side R166
MCU (IC201) side R369
● Checking the Reset/LCDREQ
signal input
Checking the MCU reset signal
Points to be checked
AnRST
MCU (IC1) side R197
MCU (IC201) side R370
LCDREQ MCU (IC1) side R184
MCU (IC201) side R227
158

TROUBLE SHOOTING

When a normal value is confirmed.
Normal voltage
(Amplitude: about 1.5V)
26.000MHz
26.000MHz
Normal voltage (3.3V)
32.768kHz
32.768kHz
When a normal value is confirmed.
When an abnormal
Normal voltage
value is confirmed.
3.3V
3.3V
3.3V
3.3V
When a normal value is confirmed.
Checking for an abnormal point
1.8V_1 has an abnormal voltage.
[MCU: IC1 and DDR2:IC2, IC3]
Remove L1 to check the voltage of the 1.8V_1.
If the voltage becomes normal, the MCU (IC1) or DDR2 (IC2, IC3)
is broken.
[MCU: IC201 & DDR2: IC202, IC203]
Remove L201 to check the voltage of the 1.8V_1.
If the voltage becomes normal, the MCU (IC1) or DDR2 (IC2, IC3)
is broken.
When an abnormal
3.3V_2 has an abnormal voltage.
value is confirmed.
[MCU]
Remove R747, L601, L403 and F601 (remove the flat cable of
CN651 and CN225, and the coaxial cable of CN652) to check the
voltage of the 3.3V_2.
If the voltage becomes normal, the device connected after having
removed the parts and flat cable, etc., is broken.
Check devices other than the BGA.
If the voltage becomes abnormal, the MCU is broken.
1.2V_3 has an abnormal voltage.
[MCU: IC1]
Remove L2 to check the voltage of the 1.2V_3.
If the voltage becomes normal, the MCU (IC1) is broken.
[MCU: IC201]
Remove L202 to check the voltage of the 1.2V_3.
If the voltage becomes normal, the MCU (IC201) is broken.
1.8V_4 has an abnormal voltage.
[MCU]
Remove F801 of the DC-DC unit (C/3) to check the voltage of the
1.8V_4.
If the voltage becomes normal, the MCU is broken.
When an abnormal
value is confirmed.
3.3V_5 has an abnormal voltage.
[MCU: IC1]
Remove F2 to check the voltage of the 3.3V_5.
If the voltage becomes normal, the MCU (IC1) is broken.
If the voltage is not corrected, there is a problem other than the BGA
parts.
SYS clock has an abnormal.
[MCU]
MCU (IC1): Replace the crystal oscillator (X1) and check the
waveform.
MCU (IC201): Replace the crystal oscillator (X201) and check the
waveform.
If the waveform is normal, the crystal oscillator is broken.
If the waveform is abnormal, the MCU is broken.
SYS_32k clock has an abnormal.
[MCU]
Remove R166 and R369 to check the waveform.
If the waveform is normal, the MCU is broken.
If the voltage is not corrected, there is a problem other than the BGA
parts.
The BGA parts are not broken.