820 3115B Green light sometimes, ON/OFF

JorgePayar

Member
ok now i have received he U7000 flat soldered these are the values in diode mode:

Pin1: 0,606v
pin2: 0,596v
pin3 0,490v
pin4 0,490v
pin5 0,705v
pin6 0,645v
pin7 0,703v
pin8 0,498v
pin9 0,690v
pin10 0,485v
pin11 0,487v
pin12 0,337v
pin13 0,443v
pin14 OL (SMC_BC_ACOK) Not present
pin15 0,704v
pin16 0,633v
pin17 0,440v
pin18 0,441v
pin19 0,432v
pin20 0,433v
pin21 0,429v
pin22 0,000v
pin23 0,441v
pin24 0,847v
pin25 0,568v
pin26 0,605v
pin27 0,602v
pin28 0,597v

pin 27/28 resistance: 20,2 Ohms
pin 17/18 resistance: 2,9 Ohms

PPBUS_G3H

f7040: 1 V and dropping

F6905: 17 V pin 1 and 2

Green light still on and off (pulsating)
R5087: 470K
I have changed u6901 cause the values were not very well I changed it green light but still pulsating...
Could be a bad SMC?

Where can I start now?
 
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JorgePayar

Member
I replaced u6900 too and some bad caps, I don't have green light yet

PPBUS_G3H: 12,5V
PP3V42_G3H: 3,4V
SMC_BC_ACOK: 2v fluctuating (u6901 pin 1 and 2)
SMC_BC_ACOK_VCC: 3,46V
ADAPTER SENSE: 3,46V
SYS_ONEWIRE: 3,46V
SMC_RESET_L: 3:46V
u7000- CHGR_ACIN: 4V
So probably is the SMC isn't it?
How can I get rid of the SMC glue properly?

Edit: I have measured PPVIN_SW_T29BST and I got 0V
PP5V_S5: I got 1,4V only

SMC_PM_G2_EN: 0V
 
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larossmann

Administrator
Staff member
oven, 225f, then some hot air and tweezers. it should become more clear looking and very soft and easy to remove in one piece. slow heat.
 

JorgePayar

Member
I´ll try to explain myself better:

NO GREEN LIGHT
Charger 60W

PP18V5_DCIN_FUSE: (F6905) 17V
PPBUS_G3H: (F7040) 12,12V
CHGR_ACIN: (U700 PIN3) 4V
CHGR_ACOK: (u7000 pin 14) 0,607 fluctuating

So it is not sending nothing?

Why is that?
Can anybody help me please? Im stuck
 
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larossmann

Administrator
Staff member
ppbus_g3h went from 12.5(good) in your last post, to 12.12(not good) in this post. this indicates the SMC is off. is SMC_RESET_L high right now, or low?
 

larossmann

Administrator
Staff member
This all points to bad SMC. Sometimes it works, sometimes it doesn't, but it never gives you a green light. Everything is there that you would need to have a green light.
 

JorgePayar

Member
Q: ok thanks, reflow here doesn't work? ( I answer to myself)
A: No, I already did, it gave me green light for a few seconds,also I have almost all power rails, but it is like BGA reballing or reflow...is BS the chip is gone.
Waiting for a new one.

I have donors board but no smc stencils anyway I ordered reballed smc.
Q: Do you work always with reballed smc nowadays or do you reball smc from donor boards sometimes?
Q: Last question: I´ve read how to bypass the smc to test the board, how can I do that?
 
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larossmann

Administrator
Staff member
when i set 400c on my jbc i get 530 on the temp measurer

when i set 1000f on the weller i get 410c on the temp measurer.

temps are pointless on gear this cheap.
 

JorgePayar

Member
Hi, Im still waiting for the preballed smc that I bought, but I´ve been reflowing the smc because this board was with liquid damage around the smc. but not directly, now what I have is a green light for 12 seconds then turns off then 12 seconds later goes on...and keep doing it. Does the smc do that? Could be something related with the clock signal?

I´ve checked that in PP1V8_S0 I got nothing but I have green light for few seconds. No fan spinning. Pads shorted nothing happens
 
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JorgePayar

Member
Ok so now I have the smc I already change the smc for a new one, reballed, and the board do the same. Goes on....and then off again green light.
What I have seen is that when I plug the charger with the battery at the same time it doesn´t appears the green light only 3 seconds instead of 8 seconds with only the charger.
I suspect must be something related with the q7055 the pin 4 with battery is steady 4.50V while when I plug the charger in is 12.50V the same pin in q7055
Do i have to replace it?
 
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JorgePayar

Member
Steady and present

pp3v42_g3h
ppbus_g3h
chgr_acin u7000 4v

fluctuating
pp5v_s5
PIN 16 U7200 12,5V

So strange

not present
pp5v_s3
pp5v_s0
pp3v_s0
pp1v8_s0
 
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JorgePayar

Member
Hi, I´ve checked SMC_RESET on u5010 pin 5 on diode mode and it is fluctuating like crazy but the other pins in u5010 are not doing crazy things. Do I have to replace it?

SMC_RESET_L: 2-3.40V then 0V....something fluctuating
SMC_BC_ACOK: 3.29V (U6901)
 
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