A2918 820-02757 - Turns on and shuts off mid-loading after replacing shorted amp

[it-solve]

This Macbook came with organic matter damage, dead bug excitements around both side amp ics. After cleaning it turned on and worked for a bit, but when I tested the audio it shut down and didnt turn on anymore. When I start measuring I detected shorted UR630.

Replaced UR630, no more shorts in the area, but I am missing PP1V8_AWAKE

Macbook starts up now, but half way loading bar shuts down and reboots, looks like when loading audio is failing?

PP1V8 - 1.79V

PP1V8_AWAKE resistance measures 70 Ohms, sounds bit low, no? I tried to inject 1.5V to see if any components warms up but not pulling any current at that voltage/resistance.

I reflowed all amps as there were corrosion around them.

These ICs are very hard to reball due to being a glass die.
Before I start pulling them out, can we confirm:

- Is 70Ohm too low for PP1V8_AWAKE
- This model should turn on without amplifiers right? Or would the clk/data detect that the ICs are not there and wont allow complete boot?

 

[2informaticos]

Possibly other audio amplifier is damaged, pulling down 1V8_AWAKE; 70 ohm is really low.
Just in case, remove first (one by one) all capacitors connected there; from the affected area.

BTW, I recently got 820-02918 board with liquid damage in the same area.
Had 64 ohm reading on 1V8_AWAKE, caused by bad UR630.
Once removed, the value increased.
However, now has 110 ohm on 3V8_AON; which is also low.
Looks like board starts now and turns off.
I am pending to receive the complete machine and audio ICs.
Very likely need to replace all of them.

 

[it-solve]

What is the best way to reball these ics?
I am struggling with these glass based ones.


hard to source these ics, yet alone a complete board. bravo

 

[2informaticos]

https://es.aliexpress.com/item/1005005301363224.html?spm=a2g0o.order_list.order_list_main.5.396b194deUdm4x&gatewayAdapt=glo2esp