a1990 820-01326 no wifi/bt

[phantomEVO]

hi guys! please help me! motherboard with shorted wifi, replaced from donor board + 2 eeprom...no luck...any idea?





WLAN_PWR_EN
PP3v3_g3s_wlan
pp1v8_g3s_wlanbt_vdd

all present

[phantomEVO]

Re: a1990 820-01326 no wifi/bt

no one?!

[corrize]

Re: a1990 820-01326 no wifi/bt

Hello, I guess there is not enought details and your pictures have too low res, we can't see anything.
I know new chip must have at least same wifi version than original, not under (for security) else bios block the working.

[phantomEVO]

Re: a1990 820-01326 no wifi/bt

you are right: here it is!

what do you mean with "wifi version?"

[corrize]

Re: a1990 820-01326 no wifi/bt

I don’t saw it’s apple laptop. I don’t know these laptops.
In pc world, the wifi version is writed in bios chip. If you replace a wifi chip v4.1 by v4, the bios block. But version 4.2, 5, 6, ok.
So check if the chip is really the same : same version wifi.

[phantomEVO]

Re: a1990 820-01326 no wifi/bt

This is a MacBook Pro…

[phantomEVO]

Re: a1990 820-01326 no wifi/bt

please help

[phantomEVO]

Re: a1990 820-01326 no wifi/bt

[mon2]

Re: a1990 820-01326 no wifi/bt

Personally do not have experience with this area but let us give it a stab.

The wifi / BT module will often be a stand alone unit that communicates with its master over UART or some similar interface (SPI / I2C / SMBUS). It appears this module uses UART mode with CMOS voltage levels (ie. NOT RS232).

In the schematic there are some multiplexers (MUX) devices shown @ U3640 and U3650. These devices must be enabled with the OE# signal. This is an active LOW signal.

If the pin #8 of each mux is LOW (0 volts), only then will the signals pass through the WIFI / BT module to the PCH (master).

Can you confirm the voltage to ground of the BTUARTMUX_OE_L signal ?

The MUXs have to enable so that the module can be configured & data can flow to / from the WIFI module to the host.

[piernov]

Re: a1990 820-01326 no wifi/bt

WiFi goes through PCIe, other busses are way too slow.

[mon2]

Re: a1990 820-01326 no wifi/bt

Well noted.

Confirm that each of the PCIe series caps are present onboard and that they are not defective. A defective / missing cap can halt the enumeration of the PCIe WIFI / BT module.