Darn, I need to read these, see correction.
I said "I'ce new" which should have been I'd knew. Sorry folks, I'm not firing
on all cylinders this morning.
Best,
Will
*********** REPLY SEPARATOR ***********
On 3/20/06 at 10:25 AM Will Matney wrote:
>Cliff,
>
>What I enjoyed about the article is it named the names of the companies
>who made the dud caps. I'ce new about this for a good while, I just never
>knew all the brands.
>
>The way electrolytic caps work is a whole horse of a different color than
>any other cap. The electrolyte in an electrolytic actually acts like the
>second plate, and not the un-anodized piece of foil. That foil is really
>just to make a connection to the electrolyte. The anodizing on the other
>foil acts as the insulator. This being the case, an electrolytic acts a
>little like a diode thus having to be polarized. So really the capacitance
>is from the electrolyte to the anodized piece of foil. If the electrolyte
>leaks, the capacitance will drop. If its chemical makeup changes, so will
>the capacitance. Once the anodizing is breached enough, you get a bang.
>
>Best,
>
>Wil
>
>*********** REPLY SEPARATOR ***********
>
>On 3/20/06 at 3:41 AM N7HIY wrote:
>
>>ah, the Hindenberg hydrogen incident of mother board electrolytics
>>and I thought they were bulging from being overfull of bytes
>>time to go out to the garage and burb my supply of ring mount CDE's
>>talk about global thermonuclear total destruction=
>>
>> snip
>>The first (and simpler) theory is that the failing capacitors can fail
>>such
>>as to form a short circuit, or with a very high leakage current,
>>overloading
>>the voltage regulators and causing them to overheat.
>>
>>The second theory is that as the capacitance decreases and the ESR
>>increases, the buck controller for the voltage regulator increases the
>>switching frequency to compensate. Since most of the MOSFET's heat output
>>is
>>produced during the switching transitions, this causes them to overheat.
>>
>>"The most common failure mode of the voltage regulator is for the MOSFET
>>to
>>short circuit, causing the system's power supply (5 or 12 volts depending
>>on
>>the motherboard) to be applied directly to the CPU, northbridge, RAM, or
>>other components, causing widespread damage and destruction. As such, a
>>motherboard with symptoms of failing capacitors should be taken out of
>>service until it is repaired, to prevent further damage."
>>
>>use cheap conterfeit knockoff parts then a cheaply designed and built
>>circuit with no crowbar overcurrent overvoltage protection, so much for
>>computer grade
>>
>>Cliff N7HIY
>>
>>
>>"They that can give up essential liberty to obtain a little temporary
>>safety
>>deserve neither liberty nor safety."
>>Benjamin Franklin, Historical Review of Pennsylvania
>>
>>
>>----- Original Message -----
>>From: "Will Matney" <craxd1@verizon.net>
>>To: <amps@contesting.com>
>>Sent: Sunday, March 19, 2006 23:55 PM
>>Subject: [Amps] Capacitor plague
>>
>>
>>> All,
>>>
>>> A very good article which I'm surprised made it to wikipedia.
>>>
>>> http://en.wikipedia.org/wiki/Capacitor_Plague
>>>
>>> Best,
>>>
>>> Will
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
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>
>
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