Help my severino is restarting:(

Hello I build few severinos but the latest one is cyclically restarting (20seconds)
I build new severino because I was thinking that I did mistake when making PCB but the new severino is broken to! i used some parts from first board to make the new one (resistors,diodes, and some ceramic capacitors and I use the same atmega8 and 168)

i write bootloader with usbasp programmer but i don’t think that is it.

Please help me it will make me mad!

Have you put in any supply decoupling in. This is something that people tend to forget. Check the pull up resistor on the reset pin is making contact. What size is it? 10K is normal.

board is made as instruction says. R11 is 10K (orange black brown gold)

what did you mean ? "Have you put in any supply decoupling in."

what did you mean ? "Have you put in any supply decoupling in."

http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

no it isn't it, I checked it on different power supples even on battery. ----------------edit--------

I unsoldered the reset pin but the problem isnt solved :( I changed almost all old parts and nothing :(

no it isn't it, I checked it on different power supples even on battery.

Even with a battery you NEED power supply decoupling. If it hasn't got any then it is a poor design and will do things like reset by itself. If you tried some and it did not solve the problem then try MORE.

Check that these is no loose connections and the code you are running has no problems. Try the simple blink code. How are you detecting it s resetting?

bootloader is running (led is blinking)( there is no sketch )

even modified blink (blinking on start) running without bootloader is showing restarts

i didnt have problems with decoupling supply with last boards (I’m using the same power supples as then)

bootloader is running (led is blinking)

Just because the LED is flashing doesn't mean the boot loader is running. Can you load a new sketch with say a different blink rate.

i didnt have problems with decoupling supply with last boards

That is absolutely no reason to say it is not a decoupling issue.

AS I said before:-

How are you detecting it is resetting?

You must have some software running that shows the resetting feature so what is it?

I modyfied blink sketch (blink 2 times at startup)
I solve problem by trading for my friends board, and it’s working fine

I solve problem by trading for my friends board,

Does that mean you friend now has the problem? ::)

Is he still you friend?

maybe he'll solve it :D It is HIS problem now :D

lol, zach. u're cruel. but seriously, this severino single sided is giving lotsa ppl (including me) problems. sigh. i wish there's a descriptive manual that describes proper technical steps in order to start the board.