MacBook Air A1466 Board 820-3209-a quarter fan spin nothing else

[No-Clean]

MacBook Air A1466 Board 820-3209-a quarter fan spin nothing else, no water damage, battery looks swollen.

SMC reset did noting.

Light turns green when charger is plugged in, then it turns orange, fan spins for a second or so then it stops, a few seconds go by then it spins again for one second and it repeats.

PPBUS_G3H 8.4
PPBUS_S5_HS_OTHER_ISNS 8.4
PPBUS_S5_HS_COPMUTING_ISNS 8.4
PPDCIN_G3H 15.07
PP3V42_G3H 3.42
PPVRTC_G3H 3.32

 

[2informaticos]

If fan spins, board is in S0 state.
Check if you get voltage on all big coils in that moment.

ALL_SYS_PWRGD goes high?
Any pulse at U1950, pins 7 & 3?
Check for corrosion around U6100, Q7950 and U1950.

Can you start in SMC bypass mode?

 

[JohnB8812]

Also check resistance between pins 17/18 and 27/28 of the ISL6259

 

[No-Clean]

If fan spins, board is in S0 state.

Check if you get voltage on all big coils in that moment.
Sorry, what big coils, Im still learning the parts names, Im a newbie.

ALL_SYS_PWRGD goes high? Pulses from 0 to 3.3v
Any pulse at U1950, pins 7 & 3? I could not find U1950 on this board
Check for corrosion around U6100, Q7950 and U1950.

U6100 looked okay but not great so I re solder it, Q7950 looks great and U1950 does not exists in thisboard.​

Can you start in SMC bypass mode?

Yes, but the only difference is that the fan spins at full sped rather than slow-medium speed.

 

[No-Clean]

Also check resistance between pins 17/18 and 27/28 of the ISL6259

I cloould not find

ISL6259 on this board​

 

[2informaticos]

"I could not find U1950 on this board"
Mea culpa; Apple use that chip number in many schematics.
In your board is U2750.

"I cloould not find
ISL6259 on this board"
Nor on page 53 (U7000)???

In SMC bypass mode, board stays on, or restarts too?

Any history available?

 

[No-Clean]

"I could not find U1950 on this board"
Mea culpa; Apple use that chip number in many schematics.
In your board is U2750.

"I cloould not find
ISL6259 on this board"
Nor on page 53 (U7000)???

In SMC bypass mode, board stays on, or restarts too?

Any history available?

In u2750 the only pin with voltage is pin 5 with a steady 3.3v not pulsing

U7000 Pins 17-18 resistance is 90.2 ko and 27-28 is 1.018 ko

SMC Bypass the fan spins at top speed for about 1 second or so and repeats, same thing as the original problem, but faster fan speed, nothing else happens.

Im puzzled!

 

[2informaticos]

"U7000 Pins 17-18 resistance is 90.2 ko and 27-28 is 1.018 ko"
Are these values between pins???
In such case you must check R7021/22 and R7051/52.
Be aware, we didn't ask about values to ground.

Please, do NOT quote an entire message visible few centimeters above; maintain forum aesthetic...

 

[JohnB8812]

Your issue is current sensing then pins 17/18 27/28. Make sure the traces between the ISL and R7020/50 are good. If so, replace all that is blown R7021/2, R7051/2, R7020/50, and the ISL as well.

 

[No-Clean]

Yes resistance was measured between pins and not to ground, I replaced

R7021/2, R7051/2, R7020/50, and the ISL,but now I dont even have a green light and no more fan spin.

Since a lot of terms are new to me I am taking LR course about basic electronics, thanks for bearing with me.​

 

[No-Clean]

One thing I noticed before and after replacing the components is that pins 17 and 18 are shorted or have continuity.

 

[No-Clean]

Ok removed U7000 and the green light came back and it turns orange, no fan spin and pins 17-18 are shorted as well as pins 27-28.

 

[2informaticos]

You MUST have practically short there (between pins); 20 ohms and 2.2 ohms respectively.
But cannot have short, nor low value respect to ground.

Is now U7000 removed?
Replace it and do NOT powre MLB again with missing chips from power supplies.
Usually nothing happens in case of ISL6259, but do NOT do that for a secondary power supply!!!

 

[JohnB8812]

If pins 17/18 and 27/28 measure 20 and 2.2, then they are NOT shorted they are exactly as they should measure. Replace the ISL properly and remeasure before powering it up. If all checks out, see if it powers on.