Re: Lenovo Ideacentre B340 ( CIH77S V1.0 ) schematic

Hi again, today I received new NCP5212 chip from ali.

I quickly installed new part and the board is working.

So - this is another possible failure - missing signal driver high.

Anton

Re: Lenovo Ideacentre B340 ( CIH77S V1.0 ) schematic

Hey that was just in time.

I have one board on the table, which is not posting.
It just spins the fan for one second.

I searched for shorts, none found.

Then I measured voltages (only spikes, as it turns on only for short time) and found that on the chip NCP5212 - I have enable signal, I have power I have ground, but I do not have PGOOD signal.

I measured also driver high and driver low. Driver high is missing. It is not shorted to gnd. I assume, that NCP5212 is...

Re: A1989 820-00850 logic board does not complete start

I studied a1989 schematics little bit,

I can assume, if I have all_sys_pwrgd signal ok, there will be problem either with U7100 or U7210, U7220, U7270, U7410, U7420, U7430.

It can be also bad CPU.

So I need to check all components around these IOs, measure some voltages and will post here.


Please correct me if I am wrong.

Hi,

1. I have macbook pro 2018 with T2 chip here which is not starting.

2. The board has none psychical damage, no liquid damage, looks like brand new.

3. I bought this macbook, previous owner said that macbook suddenly stopped working and did not turn on again.

4. I successfully restored it through DFU with apple configurator 2 and other macbook.

5. When I apply a power, the system will spins the fans for second and then after approx 30 seconds again.

6. No display at all, no startup chime. I have a trackpad click....

Re: New Members - please post your introductions here

Hi,
my name is Tony and I have hobby repairing and diagnosing electronics.

I work as RPA developer.

I found this forum by searching for problem I have with MCP early 2011. I am going to create a thread about it.