What is this diode ? (Please help me)

[thitou]

Hello everyone, I'm repairing an acer x330 led projector.

The red led no longer lights up, due to a defective diode. If you look at the picture attached, it's the one with 3115 marked on it.

Is there a technique to read the codes of the diodes?

I tried to find a replacement, but by typing this reference on the internet I get this:

https://eu.mouser.com/ProductDetail/Nexperia/PESD5Z3.3115?qs=LOCUfHb8d9vJaxAfWbkFOQ%3D%3D

Does this seem correct to you?

The red led seems to work with 5 volts (max), if this can help.

Thank you a lot   

[fzabkar]

It looks like the freewheeling diode in a stepdown DC-DC converter. Therefore, your proposed replacement is unsuitable. Instead, it would be a fast Schottky rectifier diode.

Can you identify the stepdown DC-DC converter IC? The application diagram might provide confirmation.

Otherwise, look here:

http://markingcodes.com/search/c/31

The "15" on the second line could be a date or batch code.

Here is a possible candidate:

https://nz.rs-online.com/web/p/schottky-diodes-rectifiers/2636897

https://docs.rs-online.com/4293/0900766b8101fb39.pdf (datasheet for RB051L-40)

[thitou]

Indeed, I suspected that the diode I had found was not the right one. But I didn't know how to read this code "31 15" with your indications it's a little clearer, thank you very much!

Thanks for your research, I'll see tomorrow for the DC DC converter. I'll send you a message right away.

Your link for the marking codes database very helpful!!

[thitou]

Hello,

Here is a picture of the ic. Unfortunately I couldn't find the datasheet.
The reference is 1D (or 10) 3749 N5754

Thanks! 

[fzabkar]

LT3743

https://www.analog.com/media/en/technical-documentation/data-sheets/3743fe.pdf

CBOOT (Pin 25/Pin 26):

The CBOOT pin provides a floating 5V regulated supply for the high side FET driver. An external Schottky diode is required from the VCC_INT pin to the CBOOT pin to charge the CBOOT capacitor when the switch pin is near ground.

[thitou]

Thank you for the datasheet !