UNO: No Signal at XTAL1/XTAL2 (Y2)

Using Arduino Installation & Troubleshooting
#1

my UNO is not working. I hooked up at oscilloscope to start debugging it. the crystal for the ATmega8u2 is working. so i checked the crystal feeding into the ATmega328p-mu and there is no signal.

the only LED that blinks when trying to program (fails programming) it “RX”

when I plug in the USB cable non of the LED “RX” “TX” & “L” blink, only the “ON” LED is on

both the ATmega8u2 & the ATmega328p-mu have been replaced and flashed ( or so i think)
the ATmega8u2 now shows up as an “Arduino UNO” and not a ATmega8-DFU"…
Device Instance Id
“USB\VID_2341&PID_0001\748393739333512012C1”

opti code flashed with another arduino using this method
http://www.sparkfun.com/tutorials/247

here is a scope shot during programming

800×575 78.1 KB

#2

took some more data on the scope XTAL1:

XTAL2:

The clock running at the ATmega8u2 (Y1)

here is DTS at C5.1, C5.2 (pin 2) looks like RESET.

#3

Normally you can't read the xtal pins directly unless you use a special very high impedenace scope probe designed to not load down the signal. One way to confirm that your scope probe is proper for that purpose is to attempt to scope the xtal pins on a known good operating board and see what the signals look like compaired to the board in question.

Lefty

#4

retrolefty:
Normally you can’t read the xtal pins directly unless you use a special very high impedenace scope probe designed to not load down the signal. One way to confirm that your scope probe is proper for that purpose is to attempt to scope the xtal pins on a known good operating board and see what the signals look like compaired to the board in question.

Lefty

while i do look forward to your input, and others, I have been an Electrical Technician, Electrical Engineering student & Robotic Engineering student using oscilloscope sense 2005. the scope I’m using are not cheap either, $20k-$45k, so you dont let any tom, dick & hairy with a $50 scope touch them…

This board was had its +5VDC rail touched to a +12VDC rail, killing the ATmega8u2. that is why it was replaced, by hand… :frowning:
the crystal Y2 is not connect to +VDC, only GND and the IC is new… yet its not working…

#5

No slight meant, as I had no way to know what test equipment and experiance you had. I do know that direct probing of the crystal pins is very difficult without a active FET type scope probe as shown here in the video which is worth watching.

http://www.adafruit.com/blog/2011/03/31/arduino-mega-oscillator-seen-with-fet-probe/

Lefty

#6

here is a Diecimilanova programming

bootup:

they crystal done with out a fet probe ;)

bootup watching pin 13 (SCK the "L" LED)

the UNO bootup watching SCK the "L" LED

the Y2 crystal during program .... nothing

so unless anyone else can verify, i'm gonna go with the crystal is dead and that's why its not working

#7

so i swapped ATmega328p and the UNO crystal starts working the Duemilanove crystal doesnt work.... that mean i'm not getting a signal out of XTAL1

should i program a different bootloader?

#8

i programmed all 3 chips with ATmegaBOOT_168_atmega328.hex and now the load LED acts as if its running blink but still doesnt program....

the optiboot_atmega328.hex doesnt work

#9

SOLVED: after talking with the guys at sparkfun for tech help i reprogrammed ATmega8u through the ISP header

avrdude -p at90usb82 -F -P com4 -b 19200 -c avrisp -U flash:w:UNO-dfu_and_usbserial_combined.hex -U lfuse:w:0xFF:m -U hfuse:w:0xD9:m -U efuse:w:0xF4:m -U lock:w:0x0F:m

reprogrammed the ATmega328p through the ISP header with the hex file form sparkfun

avrdude -p atmega328p -c avrisp -P com4 -b 19200 -U flash:w:optiboot_atmega328.hex -U lfuse:w:0xFF:m -U hfuse:w:0xDE:m -U efuse:w:0x05:m

#10

keaton

If you have a new UNO and it has problems don't waste that much time diagnosing the problem just return it.

If the distributor doesn't replace it and starts advising you to try to repair it yourself notify us immediately. Distributors are bound by a contract with Arduino that requires them to replace a board no questions asked.

#11