SY8104ADC(U13) got damaged

[Peeyush_Tekriwal]

Hi,

So I have a dragonBoard with which I have been playing around. I had used it a few days back and it was working fine. However, when I connected it again today it didn’t power up. Upon probing I found out that the 5V buck converter is shorted. I have no idea how it happened and I would really appreciate if you could provide me with possibilities as to what might be going wrong so that I can avoid it. I am using the LM2596 module for the external power conversion(5V to 12V) and I am giving it input using a 5V adapter.

Thanks

[danielt]

Some users have reported success replacing this component:

Voltage regulator fail

Hi there, I have a problem with my DB 410c and I was hoping someone could help. I flashed the latest Debian Image using an SD card and everything went smothly, however, when I clicked on “Continue” so the board could reboot, it freezed. I rebooted the board but nothing happened (no leds, no HDMI output, nothing), however I noticed that the consumption went to 3A (I was powering it with a bench power supply) and regulator u13 got extremely hot (in fact, I burnt my finger when I touched it). I…

[Peeyush_Tekriwal]

That’s great. Even I was planning on replacing it and giving it a shot. However, I’m more interested in as to what may have caused this issue in the first place. I don’t want to repeat this.

[doitright]

LM2596 is a step DOWN, not a step up, so the description you gave of the input through the LM2596 doesn’t make sense. If you’re using a 5V adapter through the LM2596, then you’re not going to get an output more than about 4.5 volts from the LM2596, which puts you 2 volts short of the DB410C’s input requirement.

The DB410C can be powered by anything from 6.5 to 18 volts.

So if you have it wired the way you say you do, then I’d say there is a possibility that your DB410C is fine. How about you try it again, but power it directly with a 12 volt 3 amp adapter – no LM2596.

[danielt]

@Peeyush_Tekriwal

However, I’m more interested in as to what may have caused this issue in the first place.

I can’t really say I’m afraid. The 5v regulator isn’t actually connected to very much:

• Upstream to the input jack
• Downstream to the USB type A current limiter circuits, to the HDMI transceiver, and to the LS-+5V output on the LS connector.

Of these the input jack and the LS-+5V are the things that directly expose the regulator.

PS If you have a good quality 5V input you might like to review the schematic to determine if you can desolder U13 and power with 5V only (by linking LS-DCIN and LS-+5V on the LS connector). There may not be enough headroom on the 3.7V buck converter but its worth a look.