820-01700 high fan spin no boot

[Soji]

came in with 20v with a Quater fan spin,
There is was short on the sound ic u6300 and u8220. I changed both ic.
after changing the ics. the macbook fan is speeding very high with. No boot. Black screen. Pls what can I do again.
the fan is speeding very high.

 

[2informaticos]

Did you check for USB activity and external video?
What is the final CPU core voltage?

 

[Soji]

How do I check that pls.

 

[2informaticos]

HOW TO collection

I hope this "How to" collection will help our members. I will possibly modify this post in time, if updates available. Trigger SMC_ONOFF_L (PMU_ONOFF_L): It reffers to simulate power button function, when the keyboard is not connected. We need to do this when we work with the board...

boards.rossmanngroup.com

Use an USB-C hub with HDMI output to connect external monitor/TV.

 

[Soji]

Ok I’ll do that. But the cpu is not warm.
after plugging the type-c charger 20v , the fan will just start running at its highest speed.

 

[2informaticos]

"What is the final CPU core voltage?"
Also check SMC_AVREF voltage.

 

[Soji]

No voltage on cpu core

 

[2informaticos]

Do you get 1V8_G3S?
Also check L7330 voltage.

 

[Soji]

1V8_G3S is 0.28v
no voltager on L7330
Am just having high continuous fan speed. I appreciate your response

 

[2informaticos]

1V8_G3S must appear at same time with 3V3/5V_G3S, don't you think?
All these should come on before S5 state.

 

[Soji]

Ok. I had to change the sound ic again. The fan has stopped speeding. And the fan now twitches every 1 minutes . And all the voltages are present now.
1v8G3S is present
3v3G3S is present.
5v G3S is present.
Non of the s5 rails are present.
but u8220 is getting hot intermittently I got that from the thermal camera. The fan twitches every 1 minutes

 

[2informaticos]

Remove R6361 and check again.
Test the board alone on the desk, no device connected; apart of charger, of course.

 

[Soji]

No s5 rail voltage

 

[2informaticos]

Check power rails when the fan spins.

 

[Soji]

fan will not spin. It will just twitch. It will just move a bit and stop every 2 seconds.
This morning trying to check it again I mistakenly bridged two voltage lines together and there was a spike while trying to troubleshoot and the fan started running fast again.

 

[2informaticos]

Any idea which lines?

Now the fan spins continuously?
Which voltages appear on the board?