macbook A1398 EMC 2674 no chime and black screen

[sempre]

Hi, I have a problem with macbook pro A1398 EMC 2674 (late 2013), after replacing ic Micron N25Q064A efi flash, it doesn't start anymore. when I press the power button the fans start, the screen remains off and makes no sound.
Could it be caused by invalid flash content? Have you ever had a similar problem? Any suggestions?
Thanks!

[zpi]

Re: macbook A1398 EMC 2674 no chime and black screen

Hi,

First, why did you replaced it? What was problem before?
Second, what did you changed it for? Did you just reflashed it or you used another from donor board etc?

[sempre]

Re: macbook A1398 EMC 2674 no chime and black screen

Thank you for your answer,
the flash is from the original card which was too damaged. I was able to read the chip with a programmer and it seems ok to me unfortunately I lost the chip of the board purchased as a replacement which was working before.
Tank you
Edoardo

[sempre]

Re: macbook A1398 EMC 2674 no chime and black screen

The board number is 820-3662-a

[zpi]

Re: macbook A1398 EMC 2674 no chime and black screen

As i understand, bios dump is from another board, so you need to flash Clean ME dump, you should find it in this forum, also make sure everything around bios chip is not damaged by your rework. Also if possible uploud photo of Bios area on board.

[sempre]

Re: macbook A1398 EMC 2674 no chime and black screen

Here is a photo attached

[zpi]

Re: macbook A1398 EMC 2674 no chime and black screen

Cant see very well, but doesnt pins 2 and 3 have damaged Vias throu board? Check continuity from pins 2 and 3 to coresponding resistors.

[sempre]

Re: macbook A1398 EMC 2674 no chime and black screen

Here attached are two photos a little better. Pin 3 goes to 3.3k pull up resistor, and the two? I also checked gnd and 3,3v and they are ok, for the other pins unfortunately I don't have the schematic, do you know where they are connected?
Thank you so much.

[sempre]

Re: macbook A1398 EMC 2674 no chime and black screen

Hi, a little update, I found the schematic of this motherboard and checked the connection to the flash and I'm ok. Miso and Mosi are set at 3.3v,I also checked with the oscilloscope that Miso and Mosi are set at 3.3v, there is no activity.

[dellxps15]

Re: macbook A1398 EMC 2674 no chime and black screen

looks like u used a iron to desolder the bios chip. always use hot air for more then 2 pin component solder and use flux when desoldering and soldering it back.

[piernov]

Re: macbook A1398 EMC 2674 no chime and black screen

Soldering iron is perfectly fine to desolder/solder SOIC8, just have to practice a bit on donor boards if you haven't done it yet.

[sempre]

Re: macbook A1398 EMC 2674 no chime and black screen

Actually I removed it with hot air I soldered it with a soldering iron, only I did it at least 4 times to test the flash. In the end, I didn't clean the card well. I'm pretty sure the problem is in the flash content. Is there anyone who please, before I change it (I ordered one and I'm waiting for it) who can suggest me what else to check? It seems strange to me that with the oscilloscope I cannot see the clock on pin6. Thank you

[carollwell]

Re: macbook A1398 EMC 2674 no chime and black screen

Some flash need the correct otp data.