A2159 820-01598A 18.93v/0.160amp no boot

[Mortentoft]

I've done something stupid . I have tested a new display on the A2159 mbp and suddenly I lost the screen and plug off the connector. since it can not boot more than to 0.330amp and drops back to 0.160 amp. And stats here. trackpad clicks and the fan turns. there is black screen. I have tried to install new DFU but it can not get it into DFU. it takes 18.96 (lower than normal - no battery) volts and 0.160 amp. the board is completely clean and had no damage before display change. is there anyone who can give a hint/help a newbeeee like me .
With battery it pulls over 2.2 amps and 20.3 volt.
i will be greatfull and are there any special lines I need to watch out for?
Cheers and goodnight from Denmark

 

[2informaticos]

Never move LCD connector if charger, or/and battery connected.
Do you get now USB activity?
Also check for external video; internal LCD disconnected.

 

[Mortentoft]

Hi. I know I know… i do not have any activity on USB and no external video

 

[2informaticos]

ALS and FTCAM SCL/SDA lines go directly to T2.
T2 may be now damaged, if machine is not recognized in DFU.

 

[Mortentoft]

Thank you 2informaticos. You are probably right as allways. Thank you again for you help and advice
have a good day - Greetings from Denmark.

 

[Mortentoft]

One last question for now 2informaticos. I have read a post where you describe how to put a logicboard in DFU without the keyboard. I Can not find that thread. Would you be kind explain it to me? Thank you in advanced

 

[2informaticos]

T2 has a dedicated line to force it in DFU mod; usually named SOC_FORCE_DFU.
You can use SE032 pads.

 

[Mortentoft]

Thank you 2informaticos. I managed to get the device in DFU revive it. That went well but I still need power for backlight on keyboard and picture on internal and external screen. Trackpad is tippin.

 

[2informaticos]

Which big coils get voltage on the MLB?

 

[Mortentoft]

Please take a look at enclosed picture

 

[Mortentoft]

I might have lost a few. Just let me know if you need further informations

 

[2informaticos]

What about L7702 and L7210/20?
Also check page 73.

BTW, no need to check different coils which are connected together on their output; one is good enough to check.

 

[Mortentoft]

Sorry I forgot to write you I only wrote the ones with voltage
L7702 = 0.00
L7210/20 0.00
L8100 = 0.00

 

[2informaticos]

Check diode mode on them.
Also measure voltage power and enable signals on their chips.

 

[Mortentoft]

I have messured. I hope you will be able to understand my results:
U8110=EN 3.27volt Normal.
U7710=EN 0.00 volt
U7712=Pin 5 Pp3v3 = 3.29 volt
- = Pin 4 PVCCEDRAMS0 0.00 volt
U7712 and U7710 changed without result
U7220=VIN=12.54 volt
I am working but I think I have lost my thread.

 

[2informaticos]

Why did you change a chip if doesn't receive the enable signal?

L7210/20 voltage is not expected untill all other voltages appear.
L8100 must be there even in S3 state.
I didn't see diode mode readings for L7702 and L8100.

 

[Mortentoft]

I understand your question about changing a chip without EN voltage. I lost my mind. I do not get why U7711 () and U7712 have a EN of 3.29 but why do they not work as U8112/11. They 8112/8111 have voltage on pin 5/6/4/3 as well…. U7711/12 does not
L8100 1.18 volt
L8100 diode 258
L7702 diode 033

 

[Mortentoft]

U7710 is wrong on earlier mentioned… pin 13/14 get 5.06 voltage. Sorry for that!

 

[Mortentoft]

Pin 13 = vcc
Pin 14 = pvcc
Pin 3 = pvccedrams0 EN FILT BUF = 0.00 vol

 

[2informaticos]

You've said 0V before on L8100.
1.18V is good voltage.

If no important data on the machine, try DFU restore, instead of revive.