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#31
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"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
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"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
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"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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