A1398 - 820-3787A - no P5VS4_EN 23mA current consumption

Board is not powering ON, PPBUS, PP5V_S5, and PP3V3_S5 are present. PP5V_S4 and P5VS4_EN are not present.

I have bypassed the SMC. I could see the fan running at high speed for few seconds and repeating. And the PP5V_S4 is also present. Can I know how can I proceed?

Sorry I was using a MagSafe charger with a variable power supply for measuring the current. That's the reason I didn't get P5VS4_EN .

Now I have connected an 85W charger directly, I can see the Fan is running for 5second, then stops and repeat the same.
PPBUS - 12.58V
PP5V_S5 - 5.078V
PP5V_S4 - 5.034V

PLT_RESET_L - 3.349V-fluctuating along with Fan
3V3_S5_REG is stable -3.349V



Staff member
Any history fault?

Try to start with both charger and battery connected.
Does it charge the battery at least?
When I connect battery and charger I can see a current consumption of 2.5 amp min , Seems like the battery is charging. Because I can see the green and yellow light on the charger.
Ohh my lord, I don't know what happened suddenly. I don't have a PP_bus anymore. Mag safe light is not glowing. U7100 vdd (PP5V1_CHGR_VDD) is present. I/P also present (PPDCIN_G3H_CHGR - 19.7V). SMC_RESET_L is 0V. No idea why. Have I spoiled it :cry:??


Staff member
Post basic U7100 voltages; pins 1, 2, 3, 9, 12, 13, 14, 15, 17, 19, 20, 27.
Use the pins of surrounding components as test points.
Hi Kevin,
Here is the voltages measured on U7100
pin 1 = 0V
Pin 2 = -20V
Pin3 = 4.768V
Pin9 = 0.059V
Pin12 = 0.096V
Pin13 = 0.080V
Pin14 = I couldnt measure
Pin15 = 0.0V
Pin17 = 0.255V
Pin19 = 5.475V
Pin20 = 5.479V
Pin27 = 19.76V


Staff member
"Pin12 = 0.096V"
Missing 3V42_G3H, board can't start.
Check for short at L7095 and post Q7010 and U7090 voltages.
Q7010 -
pin4 - 6.7V
pin 1 - 20.21V
pin 5 - 20.21V

pin 6 - 18.47V
pin 3 - 1.063V
pin 1 - 0.589V
pin 4 - .256V
pin 2 - 0.096V

Shall I replace LT3470AED ?
Additional info:-
I have removed U7090 and L7095. Still, there is a short (0.2Ohm) between the 2nd pin of the L7095 and GND.
In the diode - the voltage is 0V (After removing the inductor and U7090).
I couldn't measure voltage at pin 8, Because I have already removed the IC.Its clear that U7090 is not creating the short ,Still not sure what is causing the short at 3V42_G3H
What is the max current setting? I have a variable power supply with maximum 5Amp . I hope it can do the job. Additional to that I don't have a thermal camera. ☹


Staff member
"What is the max current setting?"
The MAX of your PSU; we discussed so many times on the forum about that.
The current is auto adjusted, depending by injected voltage and short resistance.
Please, try to understand Ohm law!

BTW, 5A doesn't help for short check many times.
If the short sinks more than 5A (sometime occurs even with 1V), PSU will get blocked.
It is SMC ,
SMC is getting heating up in 1.4Amp itself.
I can remove an SMC from a faulty board and replace. Is there any tutorial for reballing ? Is it mandatory to have a stencil?