820-3787 not posting ...

[Patricia]

My first post , Hi to all you nice people
please bare with me I am a total newbie at this . I tried to find similar posts to find a solution but couldnt .
I have 4 boards with exactly the same problem , at least the symptoms are exactly the same .
No liquid damage and no corrosion whatsoever. They all start and come up to 1.5A and after 3 seconds drop down to 0v and that repeats all the time . I am guessing you all will say the cpu is dead but still maybe someone have some other idea ? The boards are three 3787 and one 3662. They all have fanspin and green and orange light. They have no chime and with a usb mouse plugged in it briefly flashes and turnes off in the same pace as the boards go down to 0v. Please tell what measurements you need to make a diagnose or point me in the right direction . All if any help is highly apreciated . Thanks in advance . here are some measurements I made so far
PPDCIN_G3H 16 - 18.12 V
PPBUS_G3H - 12.58 V
PPVIN_S5_HS_OTHER5V_ISNS - 12.57 V
PPVIN_S5_HS_OTHER3V3_ISNS - 12.56 V
PPVIN_S5_HS_GPU_ISNS - 12.57 V
PPVIN_S5_HS_COMPUTING_ISNS - 12.57V
PP5V_S5 - 5.64 V
PP3V3_S5 - 3.33 V
PP5V_S4 - 5.0 V
PP3V3_S4 - 3.3V
PP5V_S3 - 5.0V
PP1V35_S3 - 1.34 V
PP3V3_S3 - 3.33 V
PPVTTDDR_S3 - 0.68 V
PP1V05_S0 - 1.05V
PPVCC_S0_CPU - 1.79V
PPVRTC_G3H 3.3V
PP3V42_G3H 3.4V
PP1V0_S0GPU_ISNS 0 V
PP1V5R1V35_S0GPU - 1.5 V
PP3V3_S0GPU - 3.3 V

 

[2informaticos]

Welcome to the forum!

All these boards have FDMF6808N as common issue.
You should start changing all 3 chips with real new FDMF6708N bought from serious store, like mouser.
Do not buy "new" FDMF6808N from chinese stores, all are refurbished!

"PP1V0_S0GPU_ISNS 0 V"
Are you sure no volt at all at L8710?
Post U8710 voltages.
This is valid for 3787 board.

 

[Patricia]

Thank you soooo much 2informaticos , you are an angel.
The L8710 has 1.05 V on both sides
The values for the U8710 does not seem right though , here they are :
1. 0 V 9. 3.3 V
2. 0 V 10. 1.08 V
3. 3.3 V 11. 2.12 V
4. 0.5 V 12. 5.6 V
5. 2.2 V 13. 5.05 V
6. 0.5 V 14. 5.06 V
7. 1.03 V 15. 4.52 V
8. 1.05 V 16 GND

I usually buy from digi key and I will order as soon as they open this morning , its 4.30 am over here now I will order FDMF6708N at least 30 pieces eventhough some may think its no idea to replace them
I like positive people so lets take a chance and still replace them .... if the CPU is dead its dead but at least I know I have tried . Thank you again 2informaticos

 

[Patricia]

ooopsss the other 8 pins didnt fit on the page , here they are

9. 3.3V
10. 1.08 V
11. 2.12 V
12. 5.6 V
13. 5.05 V
14. 5.06 V
15.4.52 V
16. GND

 

[2informaticos]

Forget about U8710, if you get 1V at L8710.
I asked about it because you missed that voltage on the first post...