exxos's Atari, Amiga & retro forum

There is a third board underneath the usb/SD card board.

There is a similar 5 pin but with different markings.

The doorbell is model WIFICDP20GY

peters wrote: 18 Mar 2025 11:33 There is a third board underneath the usb/SD card board.

There is a similar 5 pin but with different markings.

I think without the schematic or a BoM you may be out of luck.

This is the first time I've ever been able to see a blown component and it can't be identified. :-(

peters wrote: 18 Mar 2025 11:36 This is the first time I've ever been able to see a blown component and it can't be identified. :-(

Happens a lot with blown SMD, they are so small the damage is too much to identify them. I had it with my old microscope, the LED ring stopped working and it was too damaged to ID. Luckily it wasn't an expensive scope.

The RT1 component next to the blown chip is on the reverse of the board. When reassembled it would be inside the battery compartment right next to the li-ion 18650 batteries.

Could it be part of a thermal protection circuit ?

peters wrote: 18 Mar 2025 12:02 The RT1 component next to the blown chip is on the reverse of the board. When reassembled it would be inside the battery compartment right next to the li-ion 18650 batteries.

Could it be part of a thermal protection circuit ?

Difficult to say without any knowledge of what RT1 is and what it does in the circuit.

It's a black, bead like through hole 2 pin. I think it's a thermistor.

peters wrote: 18 Mar 2025 12:37 It's a black, bead like through hole 2 pin. I think it's a thermistor.

Yep likely a thermistor, but unless it has direct connections to U1 you can't say it's related. I've looked for a schematic and can't find any, the best suggestion I can make at this point is to clean the burned part with a little IPA and take a close up photo of it so we can have a go at decoding what it is based on the markings that are left.

There are no markings left, as soon as I touched it they crumbled.
There are a lot of voltage regulators like 3AC93, 3DE93 etc.

I suppose the only hope is that someone else has a working one that we can get the component number from.