newbie needs help with crystal oscillator broken

[herita]

Hi everybody,

Since i'm still a newbie in electronics and in our forum, i beg you pardon if i post a dummy question.



recently, i have broken one crystal oscillator on one toshiba mainbroad : the 14.3hz but when i have soldered it physically, i can't get my mainbroad work again.



So i ask you guys if there is any way i can test this thing to know if it still works or not ?

Thank you

[selldoor]

Re: newbie needs help with crystal oscillator broken

Are you saying you had one crystal which broke and you took it out and replaced it with a new one?

If not can you re phrase what you are saying.

How did you know the old one was broken?

[Koda]

Re: newbie needs help with crystal oscillator broken

He's probably saying he broke/knocked off the crystal. Maybe the board traces are damaged of if the mobo was operating at the time maybe working without the crystal damaged another component or the new piece is not soldered correctly.

[Duncanbest]

Re: newbie needs help with crystal oscillator broken

14.3HZ ??? WOW ! low frequency .....

[budm]

Re: newbie needs help with crystal oscillator broken

14.3HZ! No way. What number did you use to order the new one?
I.E.

[Jack Crow]

Re: newbie needs help with crystal oscillator broken

Guys,
His English is much better than my French.
Be kind here.

The French were nice to me even though I lacked the most basic language skills when the wife and I got to see Paris.

Herita,
Hi there.

Couple of things.

Those are fairly modern xtals.

Might be able to find one on a similar scrap board.
You might have to look long and hard to find one in a parts book.
Used parts are quick and best of all cheap.

Soldering them takes some work, so practice on the scrap board first with parts you do not care about. There are guys here who can give you details on what you need to un solder such a part.

How to check if they are working?

Do you have a portable short wave radio handy?

Tune it to 14.3 mHz.
Set the portable radio to tune in SSB mode.
Turn on the circuit and you should hear something in the radio.
A steady tone most likely. Adjust the tune on the radio, some of these xtals are better than others. If you do not get a tone, or have to tune more than 50khz out, then suspect the xtal of being bad.
Most are within a few HZ of what is printed on the top.

Tap the xtal case with a metal test probe.
The signal on the receiver should change level (up) and most likely frequency (tone shift in an ssb receiver). Since with a metal tool your giving the xtal a little bit of antenna for signal radiating off the case, and loading it down will cause a frequency shift of the oscillator.

I use a Sony 7600 shortwave radio for xtal spotting. Works great.

Give that a try.

Have fun
Jack Crow
Herndon Virginia USA

[kc8adu]

Re: newbie needs help with crystal oscillator broken

it probably 14.31818 mhz.

[herita]

Re: newbie needs help with crystal oscillator broken

hi, thank you all for replies, sorry for my bad english (- omg, i hadn't thought that i did so much english mistakes) , and i guess you have had a nice holiday in Paris, Jack Crow

uhm, yep, it is proably 14.31818 mhz, i think i have messed up a litle bit, thank you guys for corrections.

ok then, i will try with a short wave radio which can be used in a single side mode, the one that i belive can be found in my closet
but there is no kind of mutilmeter or multitester can check this xtals more quickly (i think that xtals can be tested with oscillator, right ?)

[selldoor]

Re: newbie needs help with crystal oscillator broken

No - it needs special equipment or an oscilloscope.
They are fairly cheap to buy so most usually just replace.
Google - "how to test a crystal oscillator"

[kc8adu]

Re: newbie needs help with crystal oscillator broken

i did that very same test a while back at a friends place in ky.
it was a custom made card in a one off cnc.ttl osc was suspected to be dead.
used the ic-7000 in my workvan to verify.it was just above the low end of 15m.
lucky guy had extras from the design of the unit.yep it is a prototype.

[herita]

Re: newbie needs help with crystal oscillator broken

cool, you guys have a lot of experiences,

i have just googled and found people tried to make some interesting tester stuff:



and i got from google also this:
http://www.ehow.com/how_8728348_test...cillators.html

but, i dont think the guy on ehow.com told us the true story ....

[Jack Crow]

Re: newbie needs help with crystal oscillator broken

H,
The idea is to 'read' the xtal in operation w/o loading it.
a scope probe offers some number of pF to ground, with a low level xtal oscillator that might be enough to pull the xtal off frequency or shut it down. If your reading the RF signal that comes off the case, no loading.

Keep it warm
Jack Crow