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Any way to fix missing solder pad / peeled pcb?

Discussion in 'PCB Layout, Design and Manufacture' started by bascotie, Dec 4, 2013.

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  1. bascotie

    bascotie

    29
    0
    Aug 21, 2013
    Hi guys,

    While removing the cmos battery on an overheating motherboard (with cat throw up to make things worse), the whole 'container' for the cmos battery popped off and one side is missing the solder pad. That side also has a strip of the green pcb peeled back.

    Wondering if I can fix this somehow? I tried resoldering as best as I could, but the computer still isn't storing the time properly.
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,397
    2,777
    Jan 21, 2010
    Post some photos. Hopefully there is enough remaining that you can pehaps epoxy the battery holder to the motherboard and run wires, or even mount the battery off-board with wires to it.
     
  3. bascotie

    bascotie

    29
    0
    Aug 21, 2013
    Ok finally got the pictures:

    [​IMG]
    [​IMG]
    [​IMG]
     
  4. bascotie

    bascotie

    29
    0
    Aug 21, 2013
    So another update:

    In an attempt to remove the battery from the small container, this happened:

    [​IMG]

    Can I just wire the battery directly? I'm a bit confused because when the battery sat in the container, it looked like only the bottom (negative) side was touching the brass contacts.
     
  5. Raven Luni

    Raven Luni

    798
    7
    Oct 15, 2011
    Those fine traces are really tricky. I tried something similar with a digital thermometer so I could panel mount it with a common power supply. I used a tiny amount of solder paste and a fine tip iron but it just kept coming away and taking the copper with it, until it was right up to the COB - game over :p
     
  6. bascotie

    bascotie

    29
    0
    Aug 21, 2013
    Yikes, wondering if I should get a pro in this case.

    The side with the missing pad just goes in a half an inch of a straight line to a hole. If I did it, would i scrape around there and try to apply solder?
     
  7. davenn

    davenn Moderator

    13,596
    1,875
    Sep 5, 2009
    yes and scrape around the via hole and on the other side of the board
    get a piece of tinned copper wire as thick as possible that will fit down the hole
    Solder it both sides and along the scrapped bit of track

    you can buy those battery holders .... it would be the ideal way of insulating the battery from the circuit board

    in the holder there will be 2 battery contacts that long one you can see it touches the smaller side of the battery, the negative terminal. And a small edge contact, that touches the large positive terminal, which I think I can see the remains of in your pic

    Dave
     
  8. bascotie

    bascotie

    29
    0
    Aug 21, 2013
    thanks Dave.

    I took it down to a family members shop and got some help. About to test it out now. He used a thick type of shrink wrap to cover the battery and two wires to each side
     
  9. dh390

    dh390

    33
    0
    Jul 30, 2013
    Replacement Coin Cell batt holders can be bought. Look on E-Bay. Also the last one I got was from my local Radio Shack (it was for the larger coin cell batteries) for a modification to a memory back-up in a home stereo receiver. The memory coin cell battery was solder to the board & I made it so the memory battery can easily be replaced without haveing to unsolder it & just having remove the bottom chassis cover.

    Also as another side note thos coin batteries are 3v so you could use a 2 cell AAA or AA batt holder with leads & sloder the leads to the pc board. All provided there is space in the unit to fit them in.

    Hope this helps. Keep us posted if it works.
     
  10. bascotie

    bascotie

    29
    0
    Aug 21, 2013
    Thanks,

    So we soldered the battery directly but it did not work. I took off the battery and measured it directly from the battery, as well as between the wires and got 1.5v both times. Looks like I may need a new battery. I believe it's a CR1220.

    Radioshack has a cr1225, will that work?
     
  11. dh390

    dh390

    33
    0
    Jul 30, 2013
    Any of the coin "CR" batteries would work as they are all 3v. The bigger the battery the longer it will run because it has higher capacity. I would get the biggest one as they usually are all the same price & the bigger one will last longer.

    As a warrning these batteries are real easy to short out because the + and - are real close together at the edges.

    You may want to look into maybe using 2 AAA or AA batteries in a holder. These are usualy cheeper & can also use rechargeable. Is there space for them?
     
    Last edited: Dec 5, 2013
  12. bascotie

    bascotie

    29
    0
    Aug 21, 2013
    The space is very tight so I don't think that thickness will work. I'm going to try a larger CR2016 battery which I have available. It's measuring 3.3V but labeled as 3V
     
  13. dh390

    dh390

    33
    0
    Jul 30, 2013
    All new batteries measure higher than their rated voltage. New AAA or AA will measure 1.6 to 1.7v. That CR2016 will work fine. And the circuit board holder Radio Shack had/s will work with that CR2016 battery.
     
  14. dh390

    dh390

    33
    0
    Jul 30, 2013
    Before you solder in the new battery check to make sure those contacts on the pc board are not shorted. Use an ohm meter & measure the resistance where the battery connects to. You don't want to junk a new battery.
     
  15. bascotie

    bascotie

    29
    0
    Aug 21, 2013
  16. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,397
    2,777
    Jan 21, 2010
    I would not recommend soldering to the batteries.
     
  17. bascotie

    bascotie

    29
    0
    Aug 21, 2013
    i ordered some holders and batteries online, will wait for them to arrive
     
  18. dh390

    dh390

    33
    0
    Jul 30, 2013
    As for soldering to batteries you need to scratch them up real good in the area you want to solder to. I use a flat blade jewelers screwdriver then I tin that area on the battery. Then tin the wire. Then solder the 2 together. All this MUST be done in a real short time as to not over heat the battery. Even alow time in between each step for the battery to cool down.

    As for your meter the lower/bottom left green area with the Omega symbol (looks like a horse shoe). The 200 setting which measures from 0 (aka dead short) to 199.99/200 ohms. If it is a touch/any over 200 the display will read OL or Ol & you would need to switch to the next higher range.

    With the power off take a reading let the #'s settle, then do the same things but with reverseing the probes & let us know what both readings are.
     
    Last edited: Dec 5, 2013
  19. bascotie

    bascotie

    29
    0
    Aug 21, 2013
    Thank you very much DH,

    I tried something like that yesterday and I kept saying "1" on the multimeter.

    So I set it to 200, positive to positive on mobo, negative to negative on mobo, and I should be getting some kind of reading above 0?

    UPDATE:

    So I set the multimeter to 200 on the omega symbol and all I see on the multimeter is a reading of "1", whether or not im trying to measure the connections, and even when I reverse the prongs.

    I want to make sure I've set it up properly. I have the ground on the multimeter plugged into "COM" and the positive to "VomegamA". Should anything be on "10ADC"?
     
    Last edited: Dec 5, 2013
  20. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,397
    2,777
    Jan 21, 2010
    Are you sure it's not OL you're seeing?

    That means there is no connectivity between the probe tips (it literally means "Open Loop"). It can also happen when the resistance is too high for the meter to read.
     
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