BigPersonalety
New member
Smc_adapter_en - 3,38v
pm_batlow_l - 0,02v
pch_dswvrmen - 3,06v
pm_DSW_dwrgd - 3,42v
pm_batlow_l - 0,02v
pch_dswvrmen - 3,06v
pm_DSW_dwrgd - 3,42v
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820-3208a liquid damage, no light on charger.
- Thread starter BigPersonalety
- Start date
=PP1V05_SUS_LDO?
If PM_BATLOW_L is not high, PCH will not start Power On Sequence.
Let see if board starts with both charger and battery connected.
Also try to start on SMC bypass mode...
If PM_BATLOW_L is not high, PCH will not start Power On Sequence.
Let see if board starts with both charger and battery connected.
Also try to start on SMC bypass mode...
BigPersonalety
New member
PP1V05_SUS - 0,1V (can’t be present since U7740, C7740, C7741 are missing)
No fan spin with battery and charger, later I will leave battery and charger connected for a bit to see if charging is happening.
sorry for stupid question, I am used to repairing iPhones, but now my son splilled something on my MacBook Air, just trying to repair it.
How do you “start on SMC by pass mode”? Couldn’t find anything on net...
Update:
if SMC bypass is achieved by pressing power button before plugging in the charger, then it didn’t work. Note that when I did this “bypass” methode when I plugged charger I saw no green light but only orange, but when I plug in JUST a charger there is green light for few second, and then orange.
Update:
So I left battery charging with this board for a night, woke up and I see a green light on charger (with battery connected) tho still no fan spin.
Also found out:
PP3V3_SUS is not present.... Thus on Q5040, PM_BATLOW_L not present (please correct me if I am wrong...),
SMC_BATLOW_L - 3,2V
No fan spin with battery and charger, later I will leave battery and charger connected for a bit to see if charging is happening.
sorry for stupid question, I am used to repairing iPhones, but now my son splilled something on my MacBook Air, just trying to repair it.
How do you “start on SMC by pass mode”? Couldn’t find anything on net...
Update:
if SMC bypass is achieved by pressing power button before plugging in the charger, then it didn’t work. Note that when I did this “bypass” methode when I plugged charger I saw no green light but only orange, but when I plug in JUST a charger there is green light for few second, and then orange.
Update:
So I left battery charging with this board for a night, woke up and I see a green light on charger (with battery connected) tho still no fan spin.
Also found out:
PP3V3_SUS is not present.... Thus on Q5040, PM_BATLOW_L not present (please correct me if I am wrong...),
SMC_BATLOW_L - 3,2V
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BigPersonalety
New member
Soo... any idea what’s wrong? Anything I need to look for?
If PM_SLP_SUS_L is low, 3V3_SUS, as 1V05_SUS too, will be missing.
PM_BATLOW_L still low if both charger and battery are connected?
PCH requires high level.
Remove Q5040 and check it again...
PM_BATLOW_L still low if both charger and battery are connected?
PCH requires high level.
Remove Q5040 and check it again...
BigPersonalety
New member
PM_BATLOW_L - 0,1V with charger + battery
Removed Q5040 - no light on charger,
Every pin on Q5040 - 0,1-0,3V
PM_SLP_SUS_L - 0V
Removed Q5040 - no light on charger,
Every pin on Q5040 - 0,1-0,3V
PM_SLP_SUS_L - 0V
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"SMC_BATLOW_L - 3,2V"
You had 3V before on pin3/Q5040...
Resolder Q5040 and measure again.
Seems to be PCH issue.
PM_BATLOW_L is pulled-up inside PCH.
You had 3V before on pin3/Q5040...
Resolder Q5040 and measure again.
Seems to be PCH issue.
PM_BATLOW_L is pulled-up inside PCH.
BigPersonalety
New member
Soo only solution is to reball/replace u1800?
Or there could be dead cap somewhere or something “minor”?
oh yes forgot to say, I put back q5040, and everything is as it was before I removed it
If PCH replacement is needed, how much does it cost? It’s just I don’t have that high tech to do it my self
Or there could be dead cap somewhere or something “minor”?
oh yes forgot to say, I put back q5040, and everything is as it was before I removed it
If PCH replacement is needed, how much does it cost? It’s just I don’t have that high tech to do it my self
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BigPersonalety
New member
Oh also if PCH replacement is needed, do I need to find u1800 exatly from 820-3208a, or there are compatible chips...?
I think buying another board is better in this case...
BigPersonalety
New member
Yes but in thoery if I replace PCH it has chance to work?
In theory, board or new PCH can also be damaged, in the rework process...
The PCH is not expensive, but change it is not easy; requires some experience.
It also needs clean ME region.
The PCH is not expensive, but change it is not easy; requires some experience.
It also needs clean ME region.
BigPersonalety
New member
I have friend who does GPU replacement quite often so I suppose there is no issue with “experience” part (he said boj cost ~25€)
And I have some 820-3209 I checked PCH SN and they match so I will try getting it from there.
maybe it’s worth first trying to reball PCH? Or there is no point and I should replace it right away?
And I have some 820-3209 I checked PCH SN and they match so I will try getting it from there.
maybe it’s worth first trying to reball PCH? Or there is no point and I should replace it right away?
For the price of new PCH, I don't recommend reball it.
Also remove it from other board, having no idea about is good or not, could be even worst...
Also remove it from other board, having no idea about is good or not, could be even worst...
BigPersonalety
New member
Hi I messed up...
I checked back everything and it appears 32k clock isn’t present... can it be cause nothing is working?
I checked back everything and it appears 32k clock isn’t present... can it be cause nothing is working?
Which 32KHZ is not present?
PCH requires SYSCLK_CLK32K_RTC.
The one for SMC (SMC_CLK32K) only appears if PCH is OK...
PCH requires SYSCLK_CLK32K_RTC.
The one for SMC (SMC_CLK32K) only appears if PCH is OK...
BigPersonalety
New member
Nah I don’t get anything on SYSCLK_CLK32K_RTC that comes from u2700.
Tried replacing u2700 nothing changed.
Previous chip looked clean and all but I tried resoldering it, but as turned out it was literary welded to the board, cause heating it with heat gun @480C for few minutes didn’t do anything. But from donor board it came relatively easy
Tried replacing u2700 nothing changed.
Previous chip looked clean and all but I tried resoldering it, but as turned out it was literary welded to the board, cause heating it with heat gun @480C for few minutes didn’t do anything. But from donor board it came relatively easy
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U2700 needs 3V at pins 2 & 13.
It will send out 3V at pin 1 and 32KHz (square wave) at pin 12.
If you don't have o-scope, DC multimeter should show aprox 0.45V DC...
It will send out 3V at pin 1 and 32KHz (square wave) at pin 12.
If you don't have o-scope, DC multimeter should show aprox 0.45V DC...
BigPersonalety
New member
Sorry for late reply.
So I checked everything works on clock chip ?
tho found shorted cap c4696, not sure if it’s relevant or not
Update, found out that PPVCORE_S0_AXG is shorted to ground
More update:
just removed that shorted cap, and what you know... a fucking fan spin ???
only thing is that... light on charger is still orange ?
So I checked everything works on clock chip ?
tho found shorted cap c4696, not sure if it’s relevant or not
Update, found out that PPVCORE_S0_AXG is shorted to ground
More update:
just removed that shorted cap, and what you know... a fucking fan spin ???
only thing is that... light on charger is still orange ?
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That means PP5V_S3 power rail is shorted to ground.
Solve that problem...
Solve that problem...