tcl-65D9 机芯：T972A10故障现象：灯亮不开机维修与分析

机型：65D9 机芯：T972A10

故障现象：灯亮不开机

维修与分析：

通电接串口打印信息显示

BL2 Built : 18:07:14, Sep 27 2019. tl1 g8337d09 – niko.he@droid05-sz

Board ID = 2

Set cpu clk to 24M

Set clk81 to 24M

Use GP1_pll as DSU clk.

DSU clk: 1200 Mhz

CPU clk: 1200 MHz

Set clk81 to 166.6M

smccc: 0001fd2f

eMMC boot @ 0

sw8 s

sd/emmc cmd 8 arg 0x00000000 status 01ff3000

DDR driver_vesion: LPDDR4_PHY_V_0_1_18 build time: Sep 27 2019 18:07:08

ddr id: 1

Load FIP HDR from eMMC, src: 0x00010200, des: 0xfffa0000, size: 0x00004000,

part:

0

fw parse done

Load ddrfw from eMMC, src: 0x0004d200, des: 0xfffa0000, size: 0x0000b000, part:

0

Load ddrfw from eMMC, src: 0x0002f200, des: 0xfffa0000, size: 0x00002800, part:

0

PIEI prepare done

fastboot data load

00000000
emmc switch 1 ok
00000000
emmc switch 2 ok
ddr saved addr:00000000
来回反复循环 量U1 T972主芯片各电压正常，怀疑主芯片和 DDR之间通讯不良，用万用表量主芯片和 DDR之间对地阻值，当量到 4U1和主芯片之间有一个过孔有 2M左右，阻值偏大，用针穿过孔，导线接，开机图像声音正常。故障排除。