820-00045-10 (It looks like it's on) No screen enable. brain dead?

I am fairly new to these boards. I have only worked 2-3 of these.
I currently have one working perfect (my road map so precious)
and two that show the [?] box on the screen. ( option + R)? I don't have a actual machine or keyboard to test with. Working on that.
and this one....


The board shows 20V on the charger and pulls 0.39A. That current draw is pretty solid and the board does not appear to be booting up. On the working board that current draw is all over the place as the CPU is pushing bits around so this appears to be doing nothing.

All the S0 rails are present.

The CPU is not enabling the screen 3V3 voltage so obviously it is not getting very far. I think it is brain dead.
All the CPU rails are normal and resistance to ground is similar to my other boards. It does not look like a shorted CPU.

I have done a physical inspection and checked all rails. I have done thermal and I see no smoking guns. It compares well to the working board. Thermal is tricky on these as the board is so small and it gets warm all over so fast. But playing back the thermal video and comparing they look the same.
 
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2informaticos

Administrator
Staff member
Could be dead CPU, as all these boards end.
Before seacrh for video, check if has USB activity.
If not, is trash; dead CPU.

You can try to reflow entire board in IR oven...
 
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have you had success in re-flowing?
The CPU is not loading the boot rom. I am more than sure of that. It does not even send the enable signal to turn the display to even try to talk to it. Never gets that far.

What about the SSD not detected? Have you seen that?
 
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2informaticos

Administrator
Staff member
CPU and SSD are the most common issues for these boards.
Never reflowed one with IR oven.
I just did a local reflow on SSD area one time; no result :mad:

I decided to refuse these machines directly...
 
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