SONOFF SV flashed with Espurna is overheating, why?

Hi All,

Not sure it it’s the right forum to post my request for help…

I recently received a SONOFF SV wireless switch, flashed it with Espurna and powered up as described on Itead’s website: default mode, jumper free, 9V input, a small siren connected to the output pins.
It works, but after a few hours becomes very hot and eventually turns off the LED and remains unavailable in HA (more details here).

I wonder why it’s happening? Any ideas how to fix it?

Are you supplying 9v DC? Check the power supply, maybe you have a bad one. Then you can try with Tasmota, if it still overheats you can have a defective unit.

yes, I use a wall PSU from Pure DAB radio :wink: DMM shows something like 12V, but it’s still within 5-24V bracket

I’ll give Tasmota or this one a go because it’s just a relay and should be easier than PIRs (like this story)

Oh no! If it’s a defective unit, I’l have to film a video (!) showing that it’s defective - bought it from Banggood, and they stupid policies on reporting problems drive me crazy… :
Have no idea how to convince them

What part of the board is getting hot? You mentioned a siren, the default is that you are powering the siren from the same supply as the SV. What is the current consumption of the SV?

I connected 9V DC to the IN terminals and the siren to the OUT ones
Did not measure the current consumption.
Mostly the part with chips on both sides (close to the RX/TX/GND header and opposite to the relay end) is getting hot.

Hmmm, that’s the esp8266 chip area.
I checked the current an unflashed SV draws by itself. 88ma with 9V input.

Is the siren the wired one with the trs plug?

You’re right, that’s the ESP chip over heating, but other chips were hot as well.
I cut off the siren’s plug and soldered it to the board.

It seems like the board is toasted now. I can connect a programmer and read/flash it, but when I power it up, the relay is clicking but no light, nothing. wth…

Do you remember if you removed the jumper?

My siren is 9V DC, but I think I tried it with or without a jumper.
Currently it’s without a jumper if it helps.

Did you end up getting that one to work or using a different one?

I ended up getting a refund and using Sonoff Basic as Sonoff S20.