how to check if xtal is working?

[ktmmotocross]

Hello.
I try to check some xtals wit my cheap osciloscope but i never get any good readings even when i measure working board.
with my osciloscope i generated 32kh signal and can be easily check. but on xtals measure only some voltage

How u measure it?

[mon2]

https://electronics.stackexchange.co...ing-multimeter

[ktmmotocross]

https://electronics.stackexchange.co...ing-multimeter

found nothing usefull in that link

[mon2]

It isn't possible. The crystal should be first inserted into an oscillator circuit and its output signal is to be read by a frequency meter or by a multimeter with the frequency meter function. The only instrument which is able to read a crystal frequency is a dip meter, a multi-purpose instrument used by radio amateurs.

fom the selected best answer on the above webpage.

[ktmmotocross]

fom the selected best answer on the above webpage.

but that is masuring outside of circuit. i need to measure inside circuit when start an i need to know why i cannot measure it

[mcplslg123]

Make sure you are using AC Coupling and not DC coupling. I can read them perfectly with my oscilloscope. Not a great one but just sufficient for my purpose. Its a UNIT 2102CEX

[ktmmotocross]

Make sure you are using AC Coupling and not DC coupling. I can read them perfectly with my oscilloscope. Not a great one but just sufficient for my purpose. Its a UNIT 2102CEX

now i see there is a switch with marking AC/DC. Coupling. what is it for?

[reformatt]

If you are measuring a crystal circuit, it's important to use 10x probes. A lot of probes may have 1x/10x switch on them. The 10x increases the attenuation but also the impedance so it will not load down the circuit your measuring. The CRO normally has a 1x/10x setting that you set to correspond to what your probes are set to. There's also a a variable cap inside the probe you use to tweak compensation. You connect the probe to the CRO's internal 1khz signal and tweak the probe till you get a flat square wave.

Xtal circuits usually have some kind of DC bias on them, so you use AC coupling in the scope to remove the DC from the measurement and then you only see the oscillations. Hard to see a 50mv AC signal superimposed on 1V of DC as your waveform will be off the screen.

[ktmmotocross]

Make sure you are using AC Coupling and not DC coupling. I can read them perfectly with my oscilloscope. Not a great one but just sufficient for my purpose. Its a UNIT 2102CEX

Mate i owe u BIG one for teach me this secrets. i just repaired my first laptop by replaced my first crystal just by blind because it signal was bad.

[mcplslg123]

Mate i owe u BIG one for teach me this secrets. i just repaired my first laptop by replaced my first crystal just by blind because it signal was bad.

It was just simple basics about using DSO. Glad it helped you.

PS: Tip for those guys who dont own a DSO about checking crystal-Measure voltage on both ends of crystal and if the voltage differs by 0.1V approx-90% chance crystal is ok.