820-2850 1/4 fan spin

Chuck60

Member
Hi I have a question. I’m getting a fan spin for about 4 seconds I test

PPBUS_G3H 12.55
PP5V_S5=5v
PP3v3_S5 = 3.3v
PP3v3_S3= pulses 0-3.3v
PP5v_S3=pulses 0-5v
PP5VS3_ENTRIP = pulsing 0-5v
PP5VS3_EN= 0-5v

U7000
Pins 28,27 = 20.4 ohms
Pins 17,18 = 3.2ohms

RTC
PCH_CLK32K_RTCX1 =0v
PCH_CLK32K_RTCX2=0v
RTC_RESET_L=3.42v
PCH_SRTCRST_L =3.42v
PPVOUT_G3H_PCH_DCRTC= 1.6v
SMC_CLK32K = 1.6v
PM_CLK32K_SUSCLK = 1.6v

u5388
1 0v Ground
2 0v Ground
3 3.42v
4 12.55
5 12.54
6= 0v Output
I replaced U5388 just in case and same problem there’s No short on CPUVCORE_HISIDE_IOUT .489v in diode mode to ground

thanks for your help
 
Last edited:

2informaticos

Administrator
Staff member
Any history available?
Did you try SMC bypass mode?

"PP3v3_S3= pulses 0-3.3v
PP5v_S3=pulses 0-5v"
I don't see any note about other S3, or S0 voltage...
 

Chuck60

Member
The only visible work done on here is FaceTime area where they ran a trace to the connector. All other s3 and S0 as I remember are pulsing I will test them. I will also retry the bypass mode and it has the same behavior with battery connected. It does charge the battery and the light turns orange
 
Last edited:

Chuck60

Member
my apologies it was a cap c8942. That was bringing it down now it chimes but fans spin up full speed immediately.Checked the sensor that are usually knocked off Or damaged but they are intact. I have no keyboard connected as I can’t find one at this moment. I will find one and get back to you
 

2informaticos

Administrator
Staff member
Run corresponding ASD EFI version and check for errors.
Try known good trackpad and flex.
Also try disconnecting webcam.
 

Chuck60

Member
the fan spinning high was keyboard I Have replaced Broken WiFi and lvds Connectors and I’m going to redo iSight traces/connector. The only issue I haven’t dealt with is a “no Bluetooth“ I’m looking at the schematics now to resolve this
But it’s booting fine and Bluetooth and FaceTime are the only thinks left :)
Thank you for your help
 

Chuck60

Member
Camera issues resolved

still no Bluetooth


continuity between u3700
U3700 Pin 1 to 23 of j3401 0.00V
U3700 Pin 2 to 21 Of j3401 0.00v
resistance to ground on j3401
Pin 23 .649v
Pin 21 . 642v
 
Last edited:

Chuck60

Member
Yes it also has continuity I was wondering if I should check it under load but I can get under the connector. Any ideas?
 
Top