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Re: Caps loadly popping on motherboard


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Thank goodness for that!

What are you working on lately Suzy? You're always doing interesting
things. Did you design an antenna?

Dorf

Re: Caps loadly popping on motherboard



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Yes, it receives its own transmissions, so lessening spectrum congestion,
not to mention propagation delay...



Re: Caps loadly popping on motherboard


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Yep, measured at 12V and polarity is correct, positive in the centre like
most of em. It's the same brand and model I have used previously. Possible
it's faulty somehow?

Michael



Re: Caps loadly popping on motherboard



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**What Voltage were the exploding caps rated for?
What Voltage did you measure on the supply?

Trevor Wilson



Re: Caps loadly popping on motherboard


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The caps are 1000uF at 10V. The power supply is meant to be 12V and the
board is meant to run on 12V. Do you know if I can replace the caps with
1000uF at a higher voltage? I've got some dead boards but can only find 1
cap that is 10V at 1000uF.

Michael



Re: Caps loadly popping on motherboard



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**What Voltage did you measure across the dead caps?

 The power supply is meant to be 12V and the
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**What Voltage did you MEASURE on the supply?

 Do you know if I can replace the caps with
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**Yes, you can. What Voltage did you measure on the supply?

 I've got some dead boards but can only find 1
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**What Voltage did you measure on the supply?

Trevor Wilson



Re: Caps loadly popping on motherboard


finger to keyboard and composed:

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This makes no sense. If the caps are original, then obviously they
weren't meant to take 12V. Either you are mistaken about the supply
voltage for your board (what is its model number?), or there are
separate +5V and +12V inputs, or the caps are on the output side of an
onboard switchmode PSU, in which case this PSU has failed.

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You may find that higher voltage caps are physically too large for
your board.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Re: Caps loadly popping on motherboard


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    He might also find that it's not only the caps which have popped, too.

Bob


Re: Caps loadly popping on motherboard


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Why doesn't it make any sense? Surely all sorts of equipment has caps in it
that are lower voltage than the input voltage. My desktop PC runs off 240V
but has 6.3 volt caps. Obviously something has to step the voltage down but
something similar could be happening with this board. The board provides 5V
out for the HDD and CD and must provide lower voltages for the CPU etc.

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I could just hang them off the board a little :-)

Michael



Re: Caps loadly popping on motherboard


finger to keyboard and composed:

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If the board has 10V caps, then it was designed so that these
particular caps would not see more than 10V. I suspect they are
probably sitting on a +5V rail. It would be quite easy to perform a
continuity test with a multimeter (with power disconnected). Are the
capacitors' positive terminals connected to the +12V input or the +5V
output? Is there are short circuit between the +12V input and the +5V
output ???

With power removed, test for continuity between the power pins at the
board's PCI slots and the various supply rails and/or capacitors.

PCI bus pinout:
 http://pinouts.ru/Slots/PCI_pinout.shtml

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Re: Caps loadly popping on motherboard


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Makes sense.


You are correct. I just tested them and they are at 4.95V.

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There doesn't appear to be.

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They all seem to be ok except for the -12V is zero. I suspect that might be
by design for this board.

The board is still running fine, I'll just replace these caps and see if
they pop again. Maybe I touched the wrong thing as it was on the bench at
the time.

Michael



Re: Caps loadly popping on motherboard


finger to keyboard and composed:

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The caps in the onboard PSU are probably 6.3V types. Maybe the PSU
failed in such a way that the input voltage was shorting to the output
??? I've never tried powering a motherboard without a CPU, but could
doing so bring about such a failure ???

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

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