need help with SMD component ID (WRT54g v2)

Discussion in 'General Electronics Chat' started by zweirecords, Jan 15, 2009.

  1. zweirecords

    Thread Starter New Member

    Jan 15, 2009
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    I was hoping someone could help identify and point me to a place to purchase a replacement SMD component on my Linksys WRT54G v2 router. I accidently broke/toasted a part of when I was trying to add an SD card to it.

    A little bit about the router: it is a Linksys WRT54G v2 with 32MB ram. The board states it is a WRT54GS REV:XB.

    The component was at position RP3 and was labeled "301." It looks exactly the same as RP4 and RP5.

    I posted the photos here on my flickr account.
    hxxp://www.flickr.com/photos/zweirecords/

    Again, I'm looking to replace this part--so if you/anyone could point me in the right direction.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    looks like RP4/RP5 are parallel resistors, 300 Ohms. They limit current for the LED displays.

    However, your RP3 is in a different location; in some signal path. What is RP2's value? (up and to the right from RP3)
     
  3. zweirecords

    Thread Starter New Member

    Jan 15, 2009
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    RP2 is labeled 620 (or 029?). My guess is 620--making it a 62 ohm resistor?

    Edit: Updated flickr with some more photos. I tried to get one of RP2.
     
    Last edited: Jan 15, 2009
  4. SgtWookie

    Expert

    Jul 17, 2007
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    Are you certain that RP3 was labeled 301? That would make it 300 Ohms.

    RP2 should be 62 Ohms. You could try testing it with an ohmmeter.
     
  5. zweirecords

    Thread Starter New Member

    Jan 15, 2009
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    I got 68 ohms across RP2 at each set of leads. RP4 and RP5 were about 300 ohms. I've been hunting for other pictures of this unit too--I'm not so sure anymore that RP3 was 301.

    This is what I was trying to do:
    hxxp://michael-tech.blogspot.com/2007/12/adding-mmcsd-card-to-linksys-wrt54g.html
    hxxp://kiel.kool.dk/pics/solderpoint_1_annotated.jpg (this might not show up so I'll post it on flickr)
     
    Last edited: Jan 15, 2009
  6. SgtWookie

    Expert

    Jul 17, 2007
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    You had better not guess about the value for RP3.

    If you are uncertain about it, you need to find out what the value is actually supposed to be.

    Perhaps you can measure the resistor pack that you zapped?
     
  7. zweirecords

    Thread Starter New Member

    Jan 15, 2009
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    Eh, no can do. Not only was it zapped, but it broke into pieces, and now I can't find it. I still can't find any pictures that show that resistor either.

    I've spent part of this morning talking to Linksys--but no luck there so far.
     
  8. zweirecords

    Thread Starter New Member

    Jan 15, 2009
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    I can now confirm that RP3 does say 620 on it--making it a 62 ohm resistor (8 terminal/4 resistors). Now if I could get some help on finding on where to purchase one!

    (I appreciate your help so far--with it, I probably would have solder something terribly wrong and really killed this router)
     
  9. zweirecords

    Thread Starter New Member

    Jan 15, 2009
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    I measured the physical size of RP2, RP4, and RP5. They all are about 3 mm X 1.5 mm--I think that makes their size 1206.
     
  10. SgtWookie

    Expert

    Jul 17, 2007
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    Size 0603 is about 1.6 x 0.8. That's about the smallest that I can deal with; 0402's are dang tiny at 1.0 x 0.5.

    It looks like the two middle traces of RP3 on the side away from the heatsink are shorted together with a solder blob. That needs to be removed. Careful application of solder wick and some heat should get it.

    Mouser has these in stock:
    http://www.mouser.com/Search/ProductDetail.aspx?qs=PnyEtmMyuGs%2bKZQOMUmBcg==
    Datasheet:
    http://www.koaspeer.com/pdfs/res25.pdf - look at the 1J4 dimensions.
    Not precisely what came on your board, but 62 Ohm resistors, 4 in parallel and isolated. Looks like it'll be just a tad wider. You'll have to be careful while soldering.

    Looking around at Digikey, came across these:
    http://www.yageo.com/pdf/yageo/Yu-YC_TC164_51_PbFree_L_2.pdf
    http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=YC164J-62CT-ND
    Minimum order is 10 pieces & $0.01/ea.
    Digikey will ship SMALL orders USPS 1st class, which will save you money.
     
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