need help identifying smd component! - Page 1
Forum section: electronics / beginners

author: Giorg
author_rank: Contributor
timestamp: January 31, 2011, 12:31:48 am
content: Hi everyone .. i'm new on the forum and i'm full of questionsI need your help to identify this little white smd component. It's directly connected to the usb data + and - line. The circuit is a usb wireless adaptor.The component has been damaged and the usb connector was brutally bended.I tought about an optocoupler but I can't find anything really similar.Is there a "quick and dirty" way to replace the component with something else?I know that it's easier to buy a new one but i'm doing it only for the pleasure of fixing stuffi hate to throw away.Thanks to all of you!

author: joelby
author_rank: Frequent Contributor
timestamp: January 31, 2011, 12:50:26 am
content: It might be a USB port terminator and/or EMI/RFI filter. ON Semi sell these (http://www.onsemi.com/PowerSolutions/parametrics.do?id=832&lctn=home), though I couldn't see one that matched yours.It's probably okay to bypass it completely for testing purposes.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 31, 2011, 11:48:12 am
content: Quote from: joelby on January 31, 2011, 12:50:26 amagree, maybe 2 EMI beads/ferrite combined together. a working bead just a short at both end, so continuity testing among pins might give some clue.

author: Zad
author_rank: Super Contributor
timestamp: January 31, 2011, 02:44:39 pm
content: It could be ferrites (and I'm pretty sure it is a common mode choke) but it could also be an ESD protection diode cluster. Somethingsimilarto this.http://www.farnell.com/datasheets/48344.pdfThis one has 6 pins, but some only needs 4+gnd.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 31, 2011, 03:18:02 pm
content: doing some digging treat on the rt2571wf chip. here's another picture from somewhere, it seems its just like two normal resistors, not sure the label, maybe 000. i bet thats the cheap replacement for the ferrites. or maybe its indeed 2 resistors joined together for smaller footprint i think, but if its 000's, then whats the point?from a forumhttp://www.hak5.org/forums/index.php?showtopic=16971and here is the best i got for the datasheet/intro of the chiphttp://www.datasheetarchive.com/rt2571*-datasheet.html

author: TheDirty
author_rank: Frequent Contributor
timestamp: January 31, 2011, 03:40:25 pm
content: 000 would just be 0 ohm jumpers. It's basically been bypassed on that board. It's possibly too expensive to add for the protection given.

author: Giorg
author_rank: Contributor
timestamp: February 02, 2011, 10:41:28 pm
content: Thank you all for the suggestions!I've done the bypass and the device it's back to life!Now i'm just wondering if it safe to leave it without protection.. as the intention is to mod it with an external homemade antenna.

author: joelby
author_rank: Frequent Contributor
timestamp: February 03, 2011, 12:32:57 am
content: It's probably fine, especially if you leave it connected to a computer all of the time, and considering that the other device pictured in this thread didn't bother to include ESD protection.

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 03, 2011, 03:05:50 am
content: afaik, ferrite is to prevent noise/spike from and to the usb data line and rt2571 from the look of the picture. you can probably damage the usb side (pc) if...1) you make unnecessary hack/mod like adding voltage to it (wireless adapter) circuit.2) there is super strong megatonne watt EMI going on around, which is very unlikely i think.as the posibility damaging the wireless adaptor due to noise from pc, well, u just bring it back from death, then what are u worrying about? the second death may means RIP baby. and i believe if you motherboard is "no shit" brand, then it is well designed to prevent such event (noise). maybe you can still keep looking for the part, or leave it as is, the same to the linked picture by me above, in the mean time, enjoy the device!ps: be aware, ferrite or no ferrite, modding the device will render the warranty voided and possibly damaging your device (manufacturer advice)

author: Giorg
author_rank: Contributor
timestamp: February 08, 2011, 08:07:14 pm
content: Quotenever say neverthanks again for all the precious information!Now i must search for something that needs to be repaired and i'll come back with more questions