Arduino burns

[hsalame]

Hello all
I posted here because I think that my problem contains power problem but I'm not sure about it and why it is happening.

I'm using in my project three things:
1- RS232_to_TTL
2- Button
3- RTC_ds1307

I burned about 10 nano and one uno and all of them burns after about 5-10 min. or maximum 15 min. while trying to find the exact problem.

I tried to use the RS232_to_ttl with arduino separately and it worked perfectly and tried the same thing with the RTC_timer and did work perfectly too.

but the problem appears once I connect both of them to the arduino and it burns again.
in all tests I kept the button not connected to be sure that the problem could be only from two things rs232_to_ttl or the RTC_timer.

Any idea what could be the problem and how to fix it.
Best regards,,

[MorganS]

Instead of using words, draw a picture of how it is all connected.

What is the power supply?

[hsalame]

The power supply is the computer USB

[MorganS]

That is really unusual. The USB power is limited to 2.5W and the computer will shut off power to the USB if it detects a problem.

Exactly which RS232 converter do you have?

[MarkT]

Are these genuine Nanos?

A full circuit diagram would be useful - perhaps the RC232 voltages are getting into the 5V logic somehow?

Have you monitored the current used? You can get USB current monitors which are handy.

If you have access to a bench power supply try using that with current limited set to a conservative value.

[hsalame]

After many more tests I found that the problem appears only when the RTC_timer is connected (I attached how I'm wiring it) so I created the circuit again without the timer and it worked perfectly.

But I don't know why it caused burning the arduino!!

Thanks for your replys.

[MorganS]

It would still be helpful to see how you wired it, not the instructions from the web page.

Don't use photos. Just use pencil and paper.

[MarkT]

So somethings wrong with the RTC module? Is it counterfeit perhaps?