Damaged Raspberry Pi: ACT & PWR LEDs Constantly On, Correct Voltages, Not Booting - Solutions?

Question

Hello, I have several pieces of damaged raspberry pi. The converters provide the correct voltages, nothing heats up, all components look functional. After inserting the memory card with the system and connecting to the power supply, both the ACT and PWR LEDs light up. They burn all the time. Has...

lukashb · Answer

How were they damaged? Do you know anything about possible causes? because, for example, it was ESD, or the voltage on the input pins was exceeded, it is unlikely to get raspberry.

Maciej_Cichy · Answer

Unfortunately, I don't know anything. I bought 8 damaged ones. One just got up and is also working in the black. 3 of them have all voltages but do not start. One has a short circuit on the u16 circuit (chipped), and 4 have 3.3 and 1.8 voltages but the voltage from the u16 circuit is missing, i.e. about 1.2v.

lukashb · Answer

It is known that there is a lack of tension, from a chip that is chipped, there is probably a good chance that Pi will get up after placing it with another model, but in the case of the rest, the matter is difficult, because it is not known who did them. Do you have the option to replace this U16? is it a matter to start because of the difficulties and complications of the process of pouring out and soldering? I haven't played with raspberry for a long time, so I don't remember what U16 is responsible for

Maciej_Cichy · Answer

From what I've read, the u16 is a controlled core power regulator. One raspberry is close to firing but after some time the ACT flashes 4 times which indicates errors in reading from the sd card. I tried with two cards and the same error.

lukashb · Answer

In that case, what does the power supply of this efficient raspberry and the one that flashes 4 times looks like?

Maciej_Cichy · Answer

According to this pinout 3.3v (is) power should be on pin 4 and this raspberry is on pin 5, i.e. CLK.

zster · Answer

So it looks like there is no voltage and what you measure on pin 5 is just a clocking waveform - a regular voltmeter will show DC voltage.

Maciej_Cichy · Answer

I also measured in a functional rasp and there is no 3.3v on this pin (4) either. Maybe it is somehow attached.

Anonymous · Answer

Measuring voltages on the card interface makes no sense. You won't diagnose anything without a decent oscilloscope or at least a logic analyzer.

Maciej_Cichy · Answer

I have a state analyzer. Where to connect

Anonymous · Answer

That's not arduino. See if the clocks start, later with the documentation of the system in turn, you have to move your head and get to where the problem is. There are no instructions on YT, plug in here and here, and this and then translate this and that.

Damaged Raspberry Pi: ACT & PWR LEDs Constantly On, Correct Voltages, Not Booting - Solutions?

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