Troubleshooting / 故障排除; Fault Diagnosis Of The Bga (Ball Grid Array) Ic - Kenwood NXR-1800 Service Manual

5.1

Fault diagnosis of the BGA (Ball Grid Array) IC

Overview
When the IC treated as Non-replaceable parts (e.g., BGA IC part) seems to be problematic, there is no way to recover/repair it and
need to proceed the unit replacement. Before proceeding the unit replacement, the following flowchart may help you to judge it.
It may be effective to try it in the following case as example, but please note that the work reliability is required because the parts
need to be removed and remount during this troubleshooting.
case: The unit seems to work as circuitry but no Power ON process visually.
BGA parts
MPU/DSP (IC33), DDR3 (IC47, IC48), eMMC (IC520), FPGA (IC60)
● Check if Power Off is set by MENU
If the display does not light up on the OLED, it may have
been Power Off by the MENU, so push the knob.
Is nothing displayed on the OLED? Or is it displayed on
the OLED, but the progress bar does not advance?
● Checking power supply
voltage (First)
Checking voltage
+B TL4000
● Checking power supply
voltage (Second)
Checking voltage
3.3V TL4002
5.0V TL4001
● Checking power supply
voltage (Third)
Checking voltage
V3_3D C524
V3_3D_LAN R270 (Power supply side)
SECTION 5
TROUBLESHOOTING / 故障排除
The OLED displays
normally.
The OLED does not
display normally.
Normal voltage
10.8 ~ 15.6V
Pass
Normal voltage
3.3V
5.0V
Pass
Normal voltage
3.3V
3.3V
Pass
The repeater is normal.
Fail
The BGA parts are not broken.
Check if the F4000 fuse is blown or Q4005 is broken.
Fail When 3.3V is an abnormal value, remove L413 and
check the following.
If the voltage of TL4002 becomes normal, it is a load
failure and the FPGA may be broken.
If the voltage of TL4002 is still abnormal, it is highly
possible that parts other than BGA parts are broken.
When 5.0V is an abnormal value, remove R4071 and
check the following.
If the voltage of TL4001 becomes normal, it is a load
failure. If the voltage is not normal, the startup sequence
may not proceed. (However, it is a defect other than BGA
parts.)
If the voltage of TL4001 is still abnormal, it is a
malfunction of the peripheral circuit including IC4000.
Fail When V3_3D is an abnormal voltage, check if the F1
fuse is blown.
If the fuse is blown and the problem is not solved even
after replacing the parts, the load is abnormal and
the MPU/DSP and eMMC may be broken.
If the fuse is normal and the gate voltage of Q3 is 3.3V,
proceed to "Check power supply voltage (Fourth)".
When V3_3D_LAN is an abnormal voltage, check if the
F2 fuse is blown.
If the fuse is blown and the abnormal value is obtained
even after replacing the parts, the load is abnormal and
the MPU/DSP may be broken.
If the fuse is normal and the gate voltage of Q2 is 3.3V,
proceed to "Check power supply voltage (Fourth)".
(No.RA094<Rev.002>)1-91