Hi Guys,

I have a 2GB usb stick which is detected as 8MB capacity under the name RAW. I'm suspecting the crystal oscillator. I have an oscillator with a probe but do not know how to use the probe and oscillator in order to check the crystal.

Could someone help me please?

Thank you

Hi,
Look on the Crystal for the number. it is either probably going to be a number with 12 or 24 in it. It is 12MHz or 24MHz

If your Oscilloscope can measure that frequency, all good, continue.

Basicaly you would need to setup your scope properly, there are many many different scopes out there, but you need to clip a ground to the GND on the PCB, and touch the probe to the crystal leg.

There are actually many resources, this being one for the search in google :
http://www.electronicrepairguide.com/how-to-test-crystal.html

BTW why do you suspect the XTAL?

also you can just by a USB or 2 and find a crystal, doesn't matter what the USB is or what size, as long as it is the same..or order one for a dollar or so and swap it out.

Thanks for your reply,

I do not know the frequency of the crystal ( nothing written on it ). To measure the frequency i have to find a ground on the usb board?

Please find attached a picure of the probe and a picture of my scope.

Thanks

and the scope

Hello Rajax, if the Crystal is not working the controller shouldn't appear at all, in any case is it possible that you show us a picture in high resolution of the pcb ( crystal side )?.

Hi ,

please find the picture of my board, i can't get a better resolution.

Sorry!

I agree, is why I asked why the OP suspected the XTAL.

The XTAL is there to supply 12MHz to the controller chip, most likely for the for the USB serial Line. Without it you would get a "A USB device connected to this computer is not recognised" or similar message.

Quite possibly you could find a (limited) data sheet for the controller and even a schematic, or whats called areference circuit - a schematic from the manufacturer showing a simple application circuit for the device. This would help you greatly in troubleshooting the electronics.

I suspect controller failure, or very possibly resistor failure, or bad solder joint.

A photo of both sides PCB and/or controller and NAND chip numbers are always good info to post along with your questions.

BTW, It is a good idea not to assume the cause of a problem, and only provide info based on it. It saves a lot of time and subsequent questions if as much info and detail is provided first.

Cheers

Ok, i agree with you with providing more info about it.

According to you, the controller is defective?

Doesn't the Samsung GT i8910 have an 8mp camera?

for future, better res pictures could be gained by shining a desk lamp across the USB board slightly, or putting the board on a table near a wall and shining the lamp on the wall to illuminate it well, but not glare. also hold the phone not too close and press the focus button or tapping the screen or whatever. Take a few and post the best.

tip - to make the filesize smaller, open in ms paint and just save. doing nothing but this can shrink the filesize 40%. Your pic went from 2.12Mb to 1.07Mb with no loss of quality. - better for you to upload and us to view

also, you can crop off the excess. I just took a screenshot of my whole screen and it was 300k.

Just trying to offer some advice for future.

Cheers

Well a bit hard to say without actually looking at it, but based on experience I would either say controller or supporting components.. possibly NAND flash is bad.

while it is too hard to read the controller number, it Looks like a very generic, cheap controller. Possibly FC or SC708, or UT something.and if so, probably has a bad quality NAND to go with it, something labelled FBNLxxxxx or PFxxx or worse just a kind of branding stamp and no number.

These are notorious for failures, and recovery can be ok, or partial by unsoldering NAND and reading chip.

Waouhh, how do you know that i have a Samsung i8910????? are you a medium?

Exif data.
Also if your gps was on when the photo was taken then the location where it was taken can be tracked. Not a lot of people know that!

yes EXIF data, and the fun of the reactions

FileAlyzer 2 if you want to play around and see exactly what you really are telling people when you simply are posting a picture. Just install, right-click a picture and see what embedded info is there.

I only looked to better advise about the picture, but people should know what is embedded in the things they the post.

Anyway, the USB...?

Hi all

I would like to point out, if it is showing 8Mb capacity, It is a lost translation table and not an electronic fault..

it looks like a CBMxxxx / Vxx STICK.. and this fault is typical of such models..

So if you agree about providing more details, then.. provide more details.. the details pertinent to a USB stick would be:

you want to fix stick or recover data?
what is the controller chip labelled as?
what is the NAND chip labelled as?
less importantly what is the brand of flash drive.

It looks to me like a SC708 or yes possibly CBMxxx or other cheapie.

Lots of these are couple with crappy NAND. though saying that, you don't know the chance of recover until you actualy unsolder the NAND and read it.

Advice: take to a lab that does Flash.