820-00164 stuck onncharging logo; no green light

elcapitan

Member
I got a water damage a1465 820-0016
that never turns on. It gets stuck lon the charging logo (low battery) when you connect the battery and magsafe. When I connect the massage without the battery; the machine turns on and shows a x on battery symbol. In both scenarios I don't get a green light at the magsafe. I already tried a brand new I/O board and cable

PPVBAT_G30_CONN 0.22v
SM_BUS_SMC_G3_SDA 0v
SM_BUS_SMC_G3_SCL 0v
PP3V42_G3H 3.42V

The diode mode reading on both SDA & SCL is .506
The resistance on pin 17 & 18 on u7100 is 3.8 ohms.

Is this a garbage battery? Thanks!
 

dukefawks

Administrator
Green light is the first thing you need. Inspect flat cable connector for corrosion especially the pin that has 3V42 on it.
 

elcapitan

Member
hey duke, i have inspected the connector for the flat cable and there isn't any corrosion on the pp3v42 pin. I have inspected the isl area and its clean. I only see some water residue on 3210. When this board first came it had green light but no power. Any idea what i should be chasing? Thanks!
 

elcapitan

Member
So i decided to take a step back and concentrate on the NO green light with the magsafe connected. Btw, I'm using a 85w magsafe.

Here are my measurements. Im clearly missing SYS_ONEWIRE thats why I dont have green light. Could this be my LIO connector? This thing is driving me nuts lool

PPBUS_G3H 8.56v
PP3V42_G3H 3.37v
SYS_ONEWIRE 0.12v
SMC_BC_ACOK 3.32

I have measured the voltage on pin 7 (SYS_NEWIRE) of the i/o flex cable when its connected to the i/o board without the motherboard and im only getting 0.50v. Does this board have a one wire circuit? Im confused and i need some sort of help if possible
 
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smiba

New member
Try a known good I/O board, the issue is probably on the board preventing SYS_ONEWIRE from working properly. The voltages are as expected and within allowable values

I have not worked on this model before but as far as I know (and can see) the SYS_ONEWIRE is located on the I/O board, yes.
 

elcapitan

Member
damn it!! I just ordered new one thinking it will address the issue but it didnt. Us there anyway to test this i/o boards?
 

smiba

New member
Might not be the I/O board then, what is the resistance to ground on SYS_ONWIRE? (With and without I/O board connected)
 

dukefawks

Administrator
SYS_ONEWIRE should be 3V42 but the pull up is on the IO board. I bet 3V42 is not making it to the IO board. Find the U6900/01 on the IO board and measure. No there is no diagram but this circuit is so simple you can easily trace it out.
 

elcapitan

Member
I just tried a new io board and cable an I'm still get no green light at the magsafe FML. Any suggestions? I'm About to throw the towel on this board :(
 

elcapitan

Member
So i decided to work again on this board. Atm, this computer, turns on completely but it doesn't show green light at the charger

1) when you connect the mag safe it shows the charging logo on the top right but no green light. The % stays at the same value the entire time. It doesnt increase the valud
2) when you connect it without the battery it shows a x
3) when you unplug the magsafe and leave the battery connected it stays on

what could be causing this fake charging?

i already tried a new battery and i/o board
 

dukefawks

Administrator
Well, SYS_ONEWIRE should have 3V on it and the pull up resistor is on the IO board. It means either the IO board is not getting 3V42 from pin 1 on J9500 or ONEWIRE has no connection to pin 9 or ACOK is not getting to the IO board on pin 11. There is nothing more to this. I assume you have a 100% known good IO board and flat cable!
 
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