I just recieved a cpu and mainboard after upgrading a friends
computer.
Upon inspection of my "new" board, I noticed many of the electrolytic
caps on the board were bloated and leaking. Just for fun, I salvaged
some caps from a few junk boards I had, and replaced all but 3
caps(didnt have that value). There are no additional specs on the caps
other than a temp rating(105C). Any suggestions? or are generic
aluminum electrolytics of the proper value (2200Uf 16V) suitable?

wrote:
I just recieved a cpu and mainboard after upgrading a friends
computer.
Upon inspection of my "new" board, I noticed many of the electrolytic
caps on the board were bloated and leaking. Just for fun, I salvaged
some caps from a few junk boards I had, and replaced all but 3
caps(didnt have that value). There are no additional specs on the caps
other than a temp rating(105C). Any suggestions? or are generic
aluminum electrolytics of the proper value (2200Uf 16V) suitable?

Use good grade 2200 uF, 16V, 105C of the same physical dimensions.

I usually get mine from Digikey, but there are many other vendors.

There's nothing special about the caps on motherboards (unless you
consider the 105C spec "special").

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wrote:

I just recieved a cpu and mainboard after upgrading a friends
computer.
Upon inspection of my "new" board, I noticed many of the electrolytic
caps on the board were bloated and leaking. Just for fun, I salvaged
some caps from a few junk boards I had, and replaced all but 3
caps(didnt have that value). There are no additional specs on the caps
other than a temp rating(105C). Any suggestions? or are generic
aluminum electrolytics of the proper value (2200Uf 16V) suitable?

They usually need to be 'low ESR' types suitable for high frequencies but seeing
as you got the replacements from other mobos, that should be just fine. 105C
rating simply lasts longer in this kind of use than the more common 85C parts.

Graham

wrote:
I just recieved a cpu and mainboard after upgrading a friends
computer.
Upon inspection of my "new" board, I noticed many of the electrolytic
caps on the board were bloated and leaking. Just for fun, I salvaged
some caps from a few junk boards I had, and replaced all but 3
caps(didnt have that value). There are no additional specs on the caps
other than a temp rating(105C). Any suggestions? or are generic
aluminum electrolytics of the proper value (2200Uf 16V) suitable?



Ideally you want low ESR caps of the same or slightly greater voltage
and temp rating. You can't go too high in most cases or they won't
physically fit in the space. I fixed a pile of boards with this problem
a few years ago, there was a huge rash of faulty capacitors.

wrote:

Upon inspection of my "new" board, I noticed many of the electrolytic
caps on the board were bloated and leaking. Just for fun, I salvaged
some caps from a few junk boards I had, and replaced all but 3
caps(didnt have that value). There are no additional specs on the caps
other than a temp rating(105C). Any suggestions? or are generic
aluminum electrolytics of the proper value (2200Uf 16V) suitable?

www.badcaps.net has lots of info, and you can't just use any 105C caps
but need those with low ESR. DigiKey.com, Mouser.com are some good
sources, but I hope that you don't need any that are 8mm diameter
because they can be hard to find in larger values.

CJT wrote:

There's nothing special about the caps on motherboards (unless you
consider the 105C spec "special").

Are you sure? Because I thought that the switching regulators on
mobos required low-ESR caps, not just any 105C caps, and that was why
different model caps were used for the regulator than for bypass, even
when all the caps were of the same brand. Also I've seen many mobos
with high quality caps in the regulator circuitry, almost always
Japanese brands, but lower quality Taiwanese or Chinese caps for
bypass, and this included budget brand mobos, like Asrock and ECS
(but not ECS' own budget brand, PCchips).

On 9 Apr 2007 02:48:11 -0700, "larry moe 'n curly"
put finger to keyboard and composed:

Also I've seen many mobos
with high quality caps in the regulator circuitry, almost always
Japanese brands, but lower quality Taiwanese or Chinese caps for
bypass, and this included budget brand mobos, like Asrock and ECS
(but not ECS' own budget brand, PCchips).

I don't know what the relationship is like today, but soon after their
merger, PCChips and ECS sold exactly the same boards under different
model names.

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

On Sun, 08 Apr 2007 19:31:50 GMT, CJT put
finger to keyboard and composed:

There's nothing special about the caps on motherboards (unless you
consider the 105C spec "special").

Some motherboards use "solid" aluminium electrolytics, eg Sanyo
OS-CON. These are claimed to have half the ESR and half the size of
equivalent liquid electrolytics.

FWIW, this is what Gigabyte has to say:
http://www.gigabyte.com.tw/FileList/..._all_solid.htm

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

Franc Zabkar wrote:

On 9 Apr 2007 02:48:11 -0700, "larry moe 'n curly"
put finger to keyboard and composed:

Also I've seen many mobos
with high quality caps in the regulator circuitry, almost always
Japanese brands, but lower quality Taiwanese or Chinese caps for
bypass, and this included budget brand mobos, like Asrock and ECS
(but not ECS' own budget brand, PCchips).

I don't know what the relationship is like today, but soon after their
merger, PCChips and ECS sold exactly the same boards under different
model names.

My ECS K7VTA3 v. 8 was identical to a PCChips mobo, except the latter
was red, lacked one set of jumper pins, and had soldered jumper wires
in place of fuses. And with another design, the ECS version had
Chemicon capacitors for the CPU voltage regulator but OST caps
everywhere else, while the PCChips version had OST everywhere. IOW
PCChips is cheap ECS' even cheaper line of mobos.

I'm taking back an ECS P4M800Pro-M mobo made for the Intel Core2 CPU
because it doesn't have STR (suspend to RAM). I can't believe that a
mobo so new would lack STR.

Franc Zabkar wrote:


On Sun, 08 Apr 2007 19:31:50 GMT, CJT put
finger to keyboard and composed:

There's nothing special about the caps on motherboards (unless you
consider the 105C spec "special").

Some motherboards use "solid" aluminium electrolytics, eg Sanyo
OS-CON. These are claimed to have half the ESR and half the size of
equivalent liquid electrolytics.

FWIW, this is what Gigabyte has to say:
http://www.gigabyte.com.tw/FileList/..._all_solid.htm

I have a Soyo retail mobo based on the intel 810i chipset, and it has
Taiwan brand
capacitors all over it, but the same mobo used by Gateway uses only
higher quality
Japanese caps, including Sanyo OS-CONs.

On 11 Apr 2007 02:01:39 -0700, "larry moe 'n curly"
put finger to keyboard and composed:

And with another design, the ECS version had
Chemicon capacitors for the CPU voltage regulator but OST caps
everywhere else, while the PCChips version had OST everywhere.

FWIW, OST do make solid caps:
http://www.ost.com.tw/PDF/SC/SC_OST_PUS.pdf

Whether PCChips uses them is another matter, though.

While I was on the OST web site, I noticed that the expected lifetimes
for capacitors when operated at their rated temperature are
surprisingly low:

http://www.ost.com.tw/products_ec_list.asp

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

It was a dark and stormy night when James Sweet
wrote:

I fixed a pile of boards with this problem
a few years ago, there was a huge rash of faulty capacitors.

I thought they were all flushed from the pipeline by now, but recently
I've seen bad ASROCK K7S41GX boards purchased about 2 years ago going
bad (one of them on my own computer, but I had sold several others and
now they're all going bad). Arrgh.

Dave