A1466 820-00165-A no power

[hgoncalves]

Hi,

I have an A1466 820-00165-A that only powers on with the SMC reset key combination. Otherwise, it tries to power on, reaches 0.545 A, fan spin for a few seconds, but then powers off and stays at 0.030 A.

Is this a known issue? Can you help?

 

[2informaticos]

Did you test the board alone on the desk?
Check U5110 voltages and SMC_LID level.

 

[hgoncalves]

Hi,

I've tested with the board alone, and it didn't power on.

I've checked it again, and I saw that R5177 was a bit corroded, and so I ireplaced. After the replacement of R5177, the board started to power on, but on the first boot, it died on the Apple logo (the screen turned black), and now it seams that it powers on, but I have no image (internal or external).

I have fan spin, voltages on all big coils, CPU gets hot, but I have no USB activity.

I think that it might be a BIOS problem. Is there any way for me to confirm that, before desoldering it?

 

[2informaticos]

You have some time dealing with Apple boards; Medusa programmer is a MUST have!

I suspect something more affected by corrosion.
Check all SPI Bus Termination resistors and traces.
Also clean J6100.

As basic rule, reball SMC when found corrosion near to it.

 

[hgoncalves]

Hi again,

I do have a medusa (by your sugestion; tks), but I already have made with medusa a clean ME, Check if SPI signals are controllable, Fix checksum of Fsys block, and forced a PRAM clean, but with no success.

I thought that I needed to flash the BIOS. Is there any thing else that I can do with medusa in these cases?

I'm going to check the SPI Bus Termination resistors and traces and reball SMC, and post the result here.

Tks.

 

[hgoncalves]

Hi,

After reballing the SMC the mac didn't power on at all.

I've replaced the SMC, and now it works fine. You're right. It was a bad SMC. TKS.

Are there any other tests that I can do with the medusa in those cases? Were the procedures that I've made with the medusa correct? Does the medusa " Check if SPI signals are controllable " checks that the values of the SPI Bus Termination resistors values and if traces are OK, or does this check other thing?

TKS!

 

[2informaticos]

If there is broken trace/resistor between SPI chip and J6100, Medusa can't work properly.
But you still need to check the resistors and traces from U6100 to SMC and PCH.

 

[hgoncalves]

Understood. Tks!