820-01700 not booting

[Kyle93]

So in this case it’s either a bad U7100 or CPU?

 

[2informaticos]

Or U4710...

 

[Kyle93]

Replaced U7100 and U4710 but no change

 

[Kyle93]

CPU replaced. L7211/21/31 is now 0.300v-0.520v fans spin but still no caps lock light or screen activity. Completed DFU restore successfully.

This board came with a i9 but it was replaced with a i7. Do any resistors need to be changed when changing to a different CPU?

 

[2informaticos]

Any CPU configuration strap should be mentioned in the schematic.

 

[Kyle93]

When I search CPU strap nothing shows up in the schematic. Do I need to use different wording to find it or does this board not have CPU configurations strap?

 

[2informaticos]

CPU configuration is shown on page 6.
Page 132 (BOM) also mentions something about various CPU types.
You should check the configuration of the MLB where you took the CPU from.

 

[Kyle93]

The CPU is a i7 2.6GHz going on a board with 64GB ram 1TB SSD and 5500M GPU.

How do you tell which resistor configuration this is based off the two pages??

 

[2informaticos]

Schematic alone probably doesn't help.
Check the CPU's donor board configuration.

BTW, what is CPU core behavior?
It should drop from 1V to 0.6V aprox.

 

[Kyle93]

What is the purpose of the donar board configuration?


When the board is powered on I do not see CPU core go to 1v. It starts at 0.2v and goes up to 0.6v

 

[2informaticos]

Usually CPU core starts with 1-1.1V and drops in few steps until 0.6-0.7V in 5-10s.

If donor board resistors are placed in the same manner as your board, then direct CPU swap should be supported.

 

[Kyle93]

Which resistors should I be looking for? This board originally came with a i9 2.4GHz CPU

The donar board which I pulled the CPU from is a i7 2.6GHZ. Is it possible for this CPU to still work if some resistors were changed in this case?

 

[2informaticos]

I never did such change, so I don't know if really need to change something.
Compare the position for the resistors from page 6.

 

[Kyle93]

page 6 shows cpu configurations 0-16 but neither page 6 or 132 show what specific cpu each 0 -16 configuration is supposed to be

 

[2informaticos]

For this reason I told you to check donor board configuration...