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Macbook A1398 820-00163 No display

M

Maxibon

Member
G;day!

Had a Macbook A1398 820-00163 in for repair after it had been dropped.

Fixed the drop by replacing the LCD cable, ( was pins were physically broken.

Also replaced U7701

Dropped off to customer, and they were happy.


Since then they plugged in a 65W charger, which made it go sideways and panic, keep rebooting and couldn't log into user.

Collect back off customer and can't work it out for the life of me.

PPVOUT_SO_LCDBKLT is .5v or not present at times.
LCDBKLT_EN_L is 12V
PPBUS_SW_LCDBKLT_PWR is 12.6
PPBUS_SW_BKL = 1.2v or less(.200 - .400 amps)
LCD_BKLT_EN is 0v

It fan spins for about 15 - 20 seconds then stops, with a little bit of a wait, it'll fan spin again shortly after.
 
M

Maxibon

Member
Thanks for your reply!

I get USB activity while the fans are spinning, but they stop, then start again shortly after, while they stop as expected, no USB.

No image either :/
 
2informaticos

2informaticos

Administrator
Staff member
Are you sure about USB activity?
Power light on USB device, doesn't mean activiy.
Read the forum, we explained (too) many times how to confirm it.
If you don't get image, no reason to search for backlight.

There could be classic FDMF6808N issue.
If you don't have real new FDMF6708/3030 to change them, you should try the script to disable CPU sleep states.
It is available somewhere on Internet, just search with patience.
 
M

Maxibon

Member
Hey thanks so much for your reply!

Appreciated as always!

I have realised that this board does not boot without the sub-board attached.

I feel silly.

I only connected it to check for HDMI and it boots correctly.

Assuming just makes an ass out of me :)
 
2informaticos

2informaticos

Administrator
Staff member
Test the board alone on the desk; disconnect anything, apart of DC cable.
Use onboard USB port to confirm activity.
 
P

piernov

Moderator
Staff member
Just as a reminder you need a known good battery connected for this machine to fully boot into macOS.
 
M

Maxibon

Member
Everything disconnected, no USB activity, just power.

I have has this mac boot without battery connected as well?
 
M

Maxibon

Member
Thanks again,

I have, everything looks fine.


Is there anything that would cause this from using the 65W charger rather then the 85W charger??

Only reason why I'm asking is it was fine, tested completely working, up until the customer used their 65W charger.

I think this is to much of a rabbit hole for me :) LOL
 
2informaticos

2informaticos

Administrator
Staff member
00163 requires 85W charger.
It will not start with 45/60W charger, unless good battery is connected.
Even with 85W charger, may not boot correctly, if no battery connected.

Customer's charger is fake one?
 
M

Maxibon

Member
It was dropped I repaired it, replaced LVDS cable and back light driver

tested and it was working fine, dropped it off, it was working fine, even chatted to the bloke for a bit, he plugged it into his charger 65W charger, and the screen flickered and macbook froze, we restarted it a few times however after logging in it would freeze shortly after and crash.

I took it back and now we here :/ Just fan spin for 30 seconds or so then stop, all power rails present.

No USB activity, no boot, no chime :(
 
2informaticos

2informaticos

Administrator
Staff member
Bad charger can only damage SMC, through SYS_ONEWIRE line.
If U7900 doesn't isolate properly this signal.
But if machine still turned on few times after, is not from charger probably.

Screen flicker and frozen machine, can point to bad GPU.
 
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