[help]imac 21,5 a1311 820-2641! is it a kind of magic?

[2informaticos]

So problem appears only when the airport card receives 3.3V power.

Try replacing Q3403 and/or U3404.

 

[phantom]

ok, problem is that i have no imac motherboard anymore...only macbook motherboards...do you know if there is something compatible ? i have a lot o a1466 and a1502 board and other boards

 

[phantom]

to replace IRFH3702TRPBF

https://www.mouser.it/datasheet/3/70/1/Infineon_IRFH3702_DataSheet_v01_01_EN.pdf

i have 820-2784, 820-2507 and 820-2733

the circtuit seems identical, but IRFH3702TRPBF is present with different names...i don't know if it is ok.. could you help me?

 

[phantom]

u3404 is the same in those boards, so i've changed it...now i should chsnge q3403, but i don't know if it is compatible. please help

 

[2informaticos]

Did you test after changing U3404?

If the MOSFETs have the same pin output, no problem to replace.

 

[phantom]

changed the mosfet too..still the same...

i don't understand the connection between no boot and wifi card, because of the fact thah the wifi pin is an "Input" from the motherboard

 

[2informaticos]

Check if board starts with airport connected and just one RAM module inserted.

 

[phantom]

edit

 

[phantom]

i'm going crazy because i'm not 100% sure like before that problem is related to wifi card. i've done dozens of tries (on/off) with and without the card:

90% of times it doesn't boot with card inserted. 10% it boot with card inserted

90% of times it boot without card, but 10% of time it doesn't boot even without card..

aslways with same behaviour (one led that disappear after power on). if the led disappear, the only way to boot the computer, is to remove and reinsert the power chord

what can i measure when i have the problem?

is there any way to boot the motherboard with my bench power supply?<

ps same problem even with 1 ddr only

 

[2informaticos]

If S5 LED goes off, test replacing Q8110.