LA_E801P Problem +RTCVCC Short Circuit

[Mainthan]

I have a problem in the la-e801p motherboard DC1 +RTCVCC short circuit with earth, I feel the cc7 capacitor short it located close to uc1.ak19 Please anybody knows the location of cc7

[mcplslg123]

Re: LA_E801P Problem +RTCVCC Short Circuit

Keeping the board on the DC1 location side, near bottom right side of cpu is CC7. You can easily trace that capacitor as it will be near 2 resistors(20K) for RTCRST# and SRTCRST#.

[Mainthan]

Re: LA_E801P Problem +RTCVCC Short Circuit

Thanks for your reply, (20K) 2 resistors are RC91 and RC93 (for RTCRST# and SRTCRST#
and That 2 capacitor CC10,CC11) I could not fine the CC7

[Th3_uN1Qu3]

Re: LA_E801P Problem +RTCVCC Short Circuit

The RTC section is in the PCH chipset. If it's got a separate PCH then it's a basic BGA rework job. If it's integrated in the CPU then you need to replace the whole board.

[mcplslg123]

Re: LA_E801P Problem +RTCVCC Short Circuit

CC7 is on the back of PCH but its very difficult to trace it without boardview.You can try injecting 1V,5A to +RTCVCC and see if any cap is getting mildly hot on back side of PCH .
Chances are probably more of a shorted PCH which will require replacement. PCH & cpu is combined on this platform-so perhaps SOC replacement will be needed.

[Mainthan]

Re: LA_E801P Problem +RTCVCC Short Circuit

Thanks for the advice, I will come back later

[Mainthan]

Re: LA_E801P Problem +RTCVCC Short Circuit

I kept little drop soldering paste tope of the capacitor (which I feel shorted cap) and inject 1V, 1A to +RTCVCC (current taken 750ma) tope of the CC7 cap soldering paste melted. Disconnect the inject supply. Removed capacitor and tested it’s short (meter reading 4 oms ) replaced cap it's ok.
Now AC LED ok, VREG3(P3) - 3.5V, VREG5(P13) - 4.95V, VIN(P12) - 19V, CS1(P1) - 0.900V , CS2(P5) - 0.700V, SW1(P18) - 4.9V, SW2(P8) -4.9V, when switch on the system not on but END1(P20) -3.25V, END2(P6) - 0V reading 4 or 5 second. Please advice me to find the fault.