820-3115 B No green light on Magsafe

Neil250

Member
PP3V42_G3H is good at 3.43 at the one wire circuit
PP_BUS_G3H: 0V
PPDCIN_S5_CHGR: 18.5V
CHGR_ACOK = 0 V

U7000

RES PINS 27-28: 20.3 Ohm
RES PINS 17-18: 3.2 Ohm

2: 17.42V
3: 4.32 V
10: 3.47 V
11:3.47 V
14: 0 V
19: 5.09 V
20: 4.93 V

R7010: 7.6 K which seems low but ACIN (PIN 3) seems good

Since the current sensing seems good and U7000 is receiving DC in fine I am assuming R7010 is OK.
CHGR_ACOK: 0 volts so no signal to ONEWIRE

U7000 needs replacement?
 
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2informaticos

Administrator
Staff member
Any voltage at R7020?
Why didn't post pin 1/U7000 too?

Looks like bad U7000.
Before change it, post exact ohm values (measured onboard) for R7080/81 and R7085/86.
 

Neil250

Member
I will post those when I get home.

Do CHGR_SGATE and CHGR_AGATE normally get shorted to ground so that the voltage dividers (R7085/R7086 and R7080/R7081)
can fully open Q7085 and Q7080?
 
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Neil250

Member
Replaced U7000

Now getting voltage in on my power source bouncing from 14.50 to 18.50

Current draw: .35 to .90A
Good news: magsafe is now green

Q7085 voltage also jumping aroung 14.5 to 18.50
 
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Neil250

Member
MAGSAFE NOW GREEN, BUT APPEARS FLICKERING
EVEN FAN IS FLICKERING AND TWITCHING BUT NEVER SPINS
voltages bouncing around
U7000 changed

PIN 1: 0-.1 V

PIN 2: 14-18 V bouncing
PIN 3: 3.38-4.3 V bouncing


PIN 14: 3.32 V
PIN 15: CHGR_BMON
PIN 16: CHGR_BGATE
PIN 17: CHGR_CSO_N
PIN 18: CHGR_CSO_P
PIN 19: 5.07 v
PIN 20: 5.04

PIN 21: CHGR_LGATE
PIN 22: PGND


PIN 26: 13-17 volts bouncing
PIN 27: CHGR_CSI_N
PIN 28: 14-18 V fluctuating
PIN 29: (AGND)THRM_PAD

RES 28-28: 20 O
RES 17-18: 3.2 O

R7010: 7.7 kO
R7011: 6.9 kO

R7085: 290 kO
R7086: 230 kO
R7020: also bouncing 14-18 V

PPBUS_G3H: bouncing 7.4-12.4 V

Q7085: shorted to ground at SOURCE (PINS1-3)



I'm pretty sure I did a good job putting U7000 in place
 
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2informaticos

Administrator
Staff member
Why did you replace U7000 so fast?
You had just a bad Q7080.

BTW, why do you post useless information???
"PIN 15: CHGR_BMON
PIN 16: CHGR_BGATE
PIN 17: CHGR_CSO_N
PIN 18: CHGR_CSO_P"

U7000 could be bad, but never change something without reason.
You should change Q7080 first.


"Q7085: shorted to ground at SOURCE (PINS1-3)"
I'm sure this is not true!!!
Remove power when check diode mode to ground; also allow 10-15s before measure.
 

Neil250

Member
U7000

pins
1: 0 V
2: 18.03 V
3: 4.378V
9: .029
12: 3.47V
13: 3.44V
14: 3.33
15: .059 V
17: 7.5-12.45 V bouncing
19: 5.07 V
20: 4.44-4.80 V bouncing
27: 14V -18 V bouncing
 

2informaticos

Administrator
Staff member
Post exact resistance between pins 17/18 and 27/28 (ohm scale).

Remove F7040 and see if get steady voltage at R7050.
 

2informaticos

Administrator
Staff member
OK, so you have a problem with a secondary power supply.
Post exact diode mode to ground at pad2/F7040 (fuse removed) and all big coils.
 

Neil250

Member
diode mode to ground at pad2/F7040: 0.464 V

diode to ground

L7100: 0.008 V
L7330: 0.14 V
L7630: 0.009V
L7220: 0.143 V
L9701: 0.439V
L3895: 0.530V

L7030: .496V

L7520: .002V
L7510: .002V
L7550: .002V



all big coils ?

as in: all coils in these power supplies?

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2informaticos

Administrator
Staff member
I don't see any strange value.
Resolder F7040 and try to start in SMC bypass mode.

Also check for voltage pulse on all big coils.

BTW, you forgot to post L7260...
 

Neil250

Member
Yeah, I tried that by turning off the power supply, shorting the power pads on the board, holding them for 15 seconds while turning power back on.
No start.

I will have to check PPBUS_G3H but before I took F7040 out I think it was pulsing as well.

My ideas now:

1) Q7950? could intermittent short on ALL_SYS_PWRGD be a factor?
2) I was going to start checking MOSFETS that were just before the coils next?...like Q7220
3) Also check U5010 with the SMC_RESET_L ?
4) Check U6990 because of a slight flicker on MAGSAFE green light?
 
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