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Bluerinse recaps a MOBO - illustrated

Discussion in 'Hardware' started by Bluerinse, Nov 24, 2006.

  1. Bluerinse
    Honorary Member

    Bluerinse Exabyte Poster

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    As I have posted recently, the occurrence of faulty motherboards due to faulty capacitors is now very common. So, for the sheer heck of it, I decided to try replacing a complete set of capacitors on a board which was to all intents and purposes FUBAR. This MOBO would either not switch on, if it did occasionally it would not POST and if it got past POST, it would crash and lock up going into Windows XP. The caps were visibly bulging and many of them were oozing brown gunk (electrolyte).

    There is text on the images explaining what stage they were taken and other info worth mentioning. Also CF is visible in the background of two of them so you can confirm this was done by yours truly yesterday.

    I needed to remove the old capacitors first, because it was impossible to read the values whilst they were on the board. Hence the first pic shows the board with all the faulty caps removed Thankfully I now have an account with RS Australia and they can supply replacements of the correct type and value.

    In this picture you can see a close up of the faulty capacitors.


    This pic shows the job half way through, you can see some new caps have been fitted and the vacant spaces for the rest to follow. Note electrolytic capacitors are not reversible, they must be fitted the right way round. Markings on this board make this task easier to accomplish.

    This picture shows the underside of the motherboard, you can get a good idea of how accurate you need to be with your soldering to pull this repair off. I have a lot of past experience repairing electronic equipment. But one might ask, what have you got to lose?

    This is the last pic and it shows the completed job.

    I immediately re-fitted the MOBO back into the case, stuck a Linux bootable distro (Knoppix) in and Bob's your uncle. Got miffed with Knoppix as it didn't detect my NIC, rebooted with Mepis next, worked like a charm. Since yesterday I have not had a single error, it is as stable as any PC I have ever used. A complete transformation. Currently it's running XP Pro from the Action Pack but I will blow that away and use this for another server, probably ISA.
     
    Certifications: C&G Electronics - MCSA (W2K) MCSE (W2K)
  2. AJ

    AJ Administrator Administrator

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    Nice one mate. Tried soldering once and made a complete pigs ear of it.

    Good to see CF on the screen :D
     
    Certifications: MCSE, MCSA (messaging), ITIL Foundation v3
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  3. simongrahamuk
    Honorary Member

    simongrahamuk Hmmmmmmm?

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    I hate our LEA's web filter! :dry
     
  4. AJ

    AJ Administrator Administrator

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    No proxy for me, I can bypass it shhhhhhh 8)
     
    Certifications: MCSE, MCSA (messaging), ITIL Foundation v3
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  5. twizzle

    twizzle Gigabyte Poster

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    Nicely done BR.

    Only thing i would say is that not all the caps on mobos are of the same value so it is important to note where each comes from. I have carried out several replacements recently at work and i change around 7 caps on 1 mobo 4 of which are different values. Unfortunatley the mobos dont not on the screen printing which values go where just the polarity of them!!

    Im glad to say that of the 3 recent replacements nota single one has yet gone faulty! (touches wood... or my head!)

    I do have the advantage when doin this of using an electronic desoldering station which helps make the removal easier. Takes the solder straight away from the holes leaving nice clean pads (well nearly all the time!)

    However i wouldnt recommend it to the untrained!! Put a cap in the wrong way and it may just go bang if your unlucky and you dont want one to explode in your face!!
     
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  6. Bluerinse
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    Bluerinse Exabyte Poster

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    I concur with everything you have said twizzle, especially this bit ^^

    However, I didn't get to be able to do these kind of things by being faint hearted :twisted:

    I have had my fair share of mini explosions and electrifying wake up calls but life goes on. Living on the edge :p
     
    Certifications: C&G Electronics - MCSA (W2K) MCSE (W2K)
  7. twizzle

    twizzle Gigabyte Poster

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    I can remeber doin my electronics course and getting diodes to burst into flames by reversing them and turning up the voltage... and getting LEDs to literally blow thier tops!!! However i was lucky never to have a Cap explode, tho we did use to play catch charged cap!!

    Now all i get is static shocks from almost every unit i touch... such a shocking personality i suppose?
     
    Certifications: Comptia A+, N+, MS 70-271, 70-272
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  8. fortch

    fortch Kilobyte Poster

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    Ha! I used to toss charged caps to the n00bs all the time in the shop. It only takes one catch to learn! :twisted:

    I've got a buddy that does recaps all the time. I've been soldering for years, but as widespread as the cheap caps were, I've not had one myself. Nice job, Bluerinse.
     
    Certifications: A+,Net+,Sec+,MCSA:Sec,MCSE:Sec,mASE
  9. Bluerinse
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    Bluerinse Exabyte Poster

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    I think they sent the whole duff batch to Australia :ohmy
     
    Certifications: C&G Electronics - MCSA (W2K) MCSE (W2K)
  10. Sparky
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    Sparky Zettabyte Poster Moderator

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    Great read :thumbleft
     
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  11. Nelix
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    Nelix Gigabyte Poster

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    I remember doing my C&G in basic electronics and the lecturer was building a small basic circuit, when he applied power the Cap blew, it was only a very small cap, a little smaller than the ones you show in the pics. He checked the polarity and thought that the cap must have been too small so got a bigger one, maybe an inch tall (not sure of the values as I can only remember the size of them). this cap also went BANG (rather loudly too), of he trots to the cupboard after checking the rest of the circuit was built correctly and picked out a cap that must have been about 5 or 6 inches high, unfortunately no one stayed around long enough to see if this one worked, the only smoke that could be seen was from all the pupils running from the lab LOL, happy days :D (sits and reminisces)
     
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