A1369 have 3 beeps how to diagnose?

[Tillie14]

Hi I am new to this forum. I am from the Netherlands, and a very newbee in repairing on motherboard level.
This is my problem I have three beeps on startup and no screen.
I have already reflow the memory modules, without success
Is there a way to find out which memory module is may be faulty or needs to be reballed before reballing all of them ?

 

[2informaticos]

First of all, welcome to the forum!

Reballing is not a definitive solution.
You should change all RAM chips.
Be aware, the problem can be also caused by CPU, or its broken traces/solders.

 

[piernov]

In general on A1369 it's not the RAM itself. 2010 is probably MCP, 2011 is more likely CPU or bad pad/trace. No definitive solution to this.

 

[Tillie14]

I found some liquid damage on the u6100, also on pin8 of the u3690 and some green corrosion on testpoint tp[1] DP_A_BIAS could this be the problem?

 

[2informaticos]

What is the 820-xxxx code of your board?

 

[Tillie14]

820-3023-A

 

[Tillie14]

Ok i will try that now

 

[Tillie14]

Do i need to remove the glue at the corners of the CPU?

 

[Tillie14]

I have heaten the CPU according your advice, but no luck. It is still beeping 3 times.
Is there a way to measure which RAM is defective?.
Or do I have to measure something else before start replacing the RAM modules.

 

[2informaticos]

No way to detect a failing RAM chip.
You can change them all, but be aware about CPU issue (maybe not RAM).

 

[Tillie14]

ok tanks for your help for now

 

[Tillie14]

One morething suggestion where to buy those RAM modules

 

[2informaticos]

You can try to remove from scrap board.
Pray the scrap board wasn't discarded for the same problem...

 

[Tillie14]

I do not have scrap boards do you know where to buy?

 

[2informaticos]

Aliexpress is the best place for scrap boards.