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"Speaker For PC Interanal BIOS Computer Motherboard Mini Onboard Case Buzzer Board Beep Alarm NEW."



 
 
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  #31  
Old December 26th 19, 01:16 AM posted to alt.comp.hardware
Norm Why[_2_]
external usenet poster
 
Posts: 114
Default "Speaker For PC Interanal BIOS Computer Motherboard Mini Onboard Case Buzzer Board Beep Alarm NEW."

[snippage]
My problem is worse than when I began. If I am not to blame, maybe there
is blown capacitor? I thought Gigabyte used plastic film caps. Maybe that
came later? I have looked at the caps and none are exploded. However when
I search the board, I see a cap with + nearby suggesting it is
electrolytic. I have intermittence problems with xBox 360 and Samsung
wide screen with my be due to keep caps. I am unable to find gibabyte
circuit diagram.

Because they are numerous, maybe I should replace all with ceramic,
plastic film or tantalum? WWW says shelf life of electrolytic capacitor
is two years. After 11 years storage they are discharged. Maybe if I
could use external 5V supply, the caps could be repolarized. Where do
test resistance so I don't start a fire?


The service life of electrolytic capacitors is 17 years
(from the webpage of Illinois Capacitor).

At the 17 year point, the rubber seal in the bottom can
dry out. However, I have a motherboard which is close
to 20 years old, and it still works.

Electrolytic capacitors with an internal pH problem, the
liquid inside will eat through the casing of the capacitor
in as little as two years. This is a defective product,
plain and simple. The electrolytic formula was a "stolen"
chemical formula, where the buffering agent was missed.
Some materials were supposed to be added to stabilize the
liquid and make it compatible with the materials around it.

Electrolytic reliability is proportional to temperature.
At 105C or greater temperatures, the life of some caps
is listed as short as 2000 hours. But modern designs, and
the recommended computer air temp of no higher than
35C to 45C or so, and the exponential in the reliability
math equation, ensures the life is many times 2000 hours.
The reliability formula is a curve-fitted Arrhenius
equation. Normal liquid chemistry reactions, the Arrhenius
rate doubles for every 7C. On capacitors, the curve fit
to the reliability data, has a doubling of rates every
15C or so. So while in chemistry class, we're taught
there is just one coefficient for that exponential,
electrical engineering shows that many items follow the
general form of the relationship, except the coefficient
needs to be curve fitted to the data. Between 45C and 105C
would be 60C or four doublings or a factor of 16. So instead
of 2000 hours, we'd get 32000 hours. And the only time
a PC is 45C, is in summer, with the AC turned off. The time
is even larger than that, because of the chilled temperatures
in winter months.

When working with plane-to-plane shorts inside PCBs, those can be
hard to find. You would, at the very least, remove all components
and carry out a visual inspection, as a starting point. And
a bench magnifier, to make things a bit bigger, helps at
a time like that. In two places I worked, we had a binocular
microscope (maybe $2000 to $3000 or so), which was a great
aid for stuff like that. You don't need too much magnification.
It's not a job for "oil immersion" or the like. (I think
the strongest microscope I've used, was 1200X or so, and used
oil immersion to some cover slips for biology work. The objective
was spring loaded because... students. You can easily crush the
glass while adjusting one of those.) PCB inspection is fine
at around 10X.

If the flaw is inside the PCB, you won't spot that visually
unless the board heats up and a burn mark appears on
the surface. The worst computer motherboard failure I've ever seen,
a ring was "charred" all the way around the CPU socket. That's
a VCore-related failure, where the current limiter didn't work properly.

Paul


Thanks for thoughtful answer. So long as PSU is plugged into wall A/C, I can
see +5V on the PS2 mouse that glows red. I'll leave it overnight to see if
there is sufficient juice to repolarize electrolytic capacitors. There is
no smoke nor fire (yet).


  #32  
Old December 26th 19, 01:22 AM posted to alt.comp.hardware
Norm Why[_2_]
external usenet poster
 
Posts: 114
Default "Speaker For PC Interanal BIOS Computer Motherboard Mini Onboard Case Buzzer Board Beep Alarm NEW."


The service life of electrolytic capacitors is 17 years
(from the webpage of Illinois Capacitor).

At the 17 year point, the rubber seal in the bottom can
dry out. However, I have a motherboard which is close
to 20 years old, and it still works.

Electrolytic capacitors with an internal pH problem, the
liquid inside will eat through the casing of the capacitor
in as little as two years. This is a defective product,
plain and simple. The electrolytic formula was a "stolen"
chemical formula, where the buffering agent was missed.
Some materials were supposed to be added to stabilize the
liquid and make it compatible with the materials around it.

Electrolytic reliability is proportional to temperature.
At 105C or greater temperatures, the life of some caps
is listed as short as 2000 hours. But modern designs, and
the recommended computer air temp of no higher than
35C to 45C or so, and the exponential in the reliability
math equation, ensures the life is many times 2000 hours.
The reliability formula is a curve-fitted Arrhenius
equation. Normal liquid chemistry reactions, the Arrhenius
rate doubles for every 7C. On capacitors, the curve fit
to the reliability data, has a doubling of rates every
15C or so. So while in chemistry class, we're taught
there is just one coefficient for that exponential,
electrical engineering shows that many items follow the
general form of the relationship, except the coefficient
needs to be curve fitted to the data. Between 45C and 105C
would be 60C or four doublings or a factor of 16. So instead
of 2000 hours, we'd get 32000 hours. And the only time
a PC is 45C, is in summer, with the AC turned off. The time
is even larger than that, because of the chilled temperatures
in winter months.

When working with plane-to-plane shorts inside PCBs, those can be
hard to find. You would, at the very least, remove all components
and carry out a visual inspection, as a starting point. And
a bench magnifier, to make things a bit bigger, helps at
a time like that. In two places I worked, we had a binocular
microscope (maybe $2000 to $3000 or so), which was a great
aid for stuff like that. You don't need too much magnification.
It's not a job for "oil immersion" or the like. (I think
the strongest microscope I've used, was 1200X or so, and used
oil immersion to some cover slips for biology work. The objective
was spring loaded because... students. You can easily crush the
glass while adjusting one of those.) PCB inspection is fine
at around 10X.

If the flaw is inside the PCB, you won't spot that visually
unless the board heats up and a burn mark appears on
the surface. The worst computer motherboard failure I've ever seen,
a ring was "charred" all the way around the CPU socket. That's
a VCore-related failure, where the current limiter didn't work properly.

Paul


Thanks for thoughtful answer. So long as PSU is plugged into wall A/C, I
can see +5V on the PS2 mouse that glows red. I'll leave it overnight to
see if there is sufficient juice to repolarize electrolytic capacitors.
There is no smoke nor fire (yet).


I lied, there is the smell of smoke. I'll leave PSU unplugged, until further
advise or I get a dream vision in my sleep.


  #33  
Old December 26th 19, 01:29 AM posted to alt.comp.hardware
Norm Why[_2_]
external usenet poster
 
Posts: 114
Default "Speaker For PC Interanal BIOS Computer Motherboard Mini Onboard Case Buzzer Board Beep Alarm NEW."

If the flaw is inside the PCB, you won't spot that visually
unless the board heats up and a burn mark appears on
the surface. The worst computer motherboard failure I've ever seen,
a ring was "charred" all the way around the CPU socket. That's
a VCore-related failure, where the current limiter didn't work properly.

Paul


Thanks for thoughtful answer. So long as PSU is plugged into wall A/C, I
can see +5V on the PS2 mouse that glows red. I'll leave it overnight to
see if there is sufficient juice to repolarize electrolytic capacitors.
There is no smoke nor fire (yet).


I lied, there is the smell of smoke. I'll leave PSU unplugged, until
further advise or I get a dream vision in my sleep.


Oops, smell of smoke may be normal when fans are not blowing. I think I need
a Christmas Day dream vision. There is no peyote in this town.


 




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