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#11
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Getting there
Thanks. I should mention that at this point I have one 500 MB RAM
stick installed with the Intel heat sink cooler on the CPU. Maybe I will try a no RAM boot. If I can get into BIOS I can tweak it. I have BARTPE (preinstallation edition based on WinXP). On it I have the BIOS F2 upgrade. If I can boot BARTPE and install BIOS v2.0 I'm home free. I removed the one RAM stick to see if I got different beep codes. Nope. 'Continuous short beeps: Power error' takes priority. This means the annoying beep speaker can be removed and the system can be allowed to recycle. Paul gave a link where GA-EP45-DS3L MOBO eventually POSTed. With Q9650, I could feel heat radiated. E4700 is cold. I can still feel heat coming from somewhere but face is not directional. Touching does not reveal hot spot. Going through MOBO I found a ten-pin keyed connector not plugged in. I removed all power to peripherals, like DVD R/W drive. Like Louis Rossmann, I think I need to find a component that is "shorting", (an active short?). Where to find such tool? The claim here is the continuous short beeps are a RAM error. GA-EP45-DS3L ? I reseated my 500 MB RAM. https://forums.tweaktown.com/gigabyt...t-beeps-4.html It almost seems like a half-finished BIOS design or something. Some RAMs working, other RAMs not working, participants going crazy with the custom settings. I had less trouble with my VIA chipset board than that :-) (That was the board where the chipset actually works with 2GB RAM DIMMs, but the BIOS was never "tuned" to use the right Tsu and Th and the like. When I used the 1GB sticks I had, that board was flawless. Long Prime95 runs, no problem at all. BIOS issues can make an awful mess when they happen.) Paul Thanks Paul. I got a non-contact infrared thermometer and found heat was generated in all the usual suspects: components with heat sink radiators. I keep the room thermostat at 15 C and allow heat from xBox 360 and Samsung plasma TV to keep it warm. Tonight outside temperature should get down to 8 C. I'll turn off thermostat and electronics and let the room get cold. With recycle the GA-EP45-DS3L MOBO might POST. On the other hand, "Semiconductor materials (carbon, silicon, germanium) typically have negative temperature coefficients of resistance." From: https://www.allaboutcircuits.com/tex...nt-resistance/ So maybe the room is too cold for the GA-EP45-DS3L to POST? In the fossil record, I see no sign of such a temperature related problem. There may have been one or two chipsets long ago, where something about the circuit was temperature sensitive. But that is by no means a common situation. It's an outlier. Saturating logic circuits can successfully run from -55C to way way above the boiling point of water. They're not snowflakes, but you have to select the right items for the job. I found a processor the other day, for automotive usage, which goes way outside the range of anything I've ever used. I have a P45 here, and it's never had a problem starting. That's the refurb Optiplex with a dual core in it. Room temperature is the temperature it's *supposed* to work at. Sure, some electronics have trouble at -20C (maybe LED lightbulbs or some pedestal box for ATT), but that's considered one extreme of the temperature range. On the high end, it's a function of what simulation temperature the circuit was verified at. Like at work, maybe you'd set the simulation temperature to 105C for margining, even though you had no intention of ever running an actual chip at that temperature. CMOS gets slower at high temperature, and you're checking for timing failures by using a simulation temperature that high. Then the idea is, operation at temperatures below that is just fine and dandy. Where circuits have problems, is in the ad-hoc circuit used for backfeed protection and parts of the reset circuit. Some of these rely on analog voltages and capacitors, and occasionally some booboo in there causes a motherboard to have a temperature issue. It's not normal for pure-digital circuits (Northbridge/Southbridge/CPU) to become "wobbly" with temp. On the Southbridge, the only problem I've heard of, is the RTC and CMOS RAM, the RAM may not function at reduced voltage (CMOS battery getting weak) and at some non-room temperature. Some of these conditions when they happened, were considered to be functional failures and the chipset should never have been shipped that way. Again, this is not a common condition, and there hasn't been a problem like that in yonks. Have you tried your one-stick-of-RAM test, in each of the four slots individually ? Don't forget to remove all power from the system, before moving the stick of RAM. That means switch off at the back or unplug the PC power cable, wait *at least* 30 seconds for 5VSB to drain. Asus motherboards all have a green LED onboard, that monitors +5VSB and when that LED extinguishes, then it's safe to move RAM. I don't know how many other brands have that. On some motherboards, there is the chicken-versus-egg problem, where the user needs to change BIOS versions, the board won't come up, and you can't flash the BIOS. Your board has a Dual BIOS, and by now, probably both sides have the same BIOS version. That would be another variable at this point. That's what the hope of using some other processor was about - getting the board to start by using an alternate processor, so the BIOS version could get changed when you wanted to change it. For removable BIOS chips, you could flash them using a lab programmer. But I no longer have access to stuff like that, and I don't know of any computer stores in town who I would expect to own such equipment. My newest motherboard here, has its own flasher onboard. You can change the BIOS version, *without* a CPU being in the CPU socket. There is a special USB port, you plug in a flash stick with a BIOS image on it, there's a pushbutton on the back of the PC, you press that, and a few minutes later, the machine has a new BIOS version. I've never used the feature, but the feature sure was attractive when I bought it. Because, it meant I "couldn't be held hostage by a motherboard refusal-to-start". There is a microcontroller next to the USB port, that reads the flash stick and writes the BIOS chip with what it finds. What used to cost $150, now costs a buck to do. Paul Thanks Paul, I messed around with temperature enough. The MOBO has been recycling in a hot room. The infrared thermometer allows me to do controlled but pointless experiments with a hairdryer. I have now taken some voltages. Where I removed a 470 uF 16V capacitor allows me to measure 12V rail. It goes up to 12V steady each cycle. The vacant PCI slot allows me to measure 5V again. Now it shows 0V, no 5V. No 5V explains the beep codes: Q: What do the beeps emitted during the POST mean? A: The following Award BIOS beep code descriptions may help you identify possible computer problems. (For reference only.) 1 short: System boots successfully 2 short: CMOS setting error 1 long, 1 short: Memory or motherboard error 1 long, 2 short: Monitor or graphics card error 1 long, 3 short: Keyboard error 1 long, 9 short: BIOS ROM error Continuous long beeps: Graphics card not inserted properly Continuous short beeps: Power error No 5V is a major power error. But why now? |
#12
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Getting there
[snippage]
On the other hand, "Semiconductor materials (carbon, silicon, germanium) typically have negative temperature coefficients of resistance." From: https://www.allaboutcircuits.com/tex...nt-resistance/ So maybe the room is too cold for the GA-EP45-DS3L to POST? In the fossil record, I see no sign of such a temperature related problem. There may have been one or two chipsets long ago, where something about the circuit was temperature sensitive. But that is by no means a common situation. It's an outlier. Saturating logic circuits can successfully run from -55C to way way above the boiling point of water. They're not snowflakes, but you have to select the right items for the job. I found a processor the other day, for automotive usage, which goes way outside the range of anything I've ever used. I have a P45 here, and it's never had a problem starting. That's the refurb Optiplex with a dual core in it. Room temperature is the temperature it's *supposed* to work at. Sure, some electronics have trouble at -20C (maybe LED lightbulbs or some pedestal box for ATT), but that's considered one extreme of the temperature range. On the high end, it's a function of what simulation temperature the circuit was verified at. Like at work, maybe you'd set the simulation temperature to 105C for margining, even though you had no intention of ever running an actual chip at that temperature. CMOS gets slower at high temperature, and you're checking for timing failures by using a simulation temperature that high. Then the idea is, operation at temperatures below that is just fine and dandy. Where circuits have problems, is in the ad-hoc circuit used for backfeed protection and parts of the reset circuit. Some of these rely on analog voltages and capacitors, and occasionally some booboo in there causes a motherboard to have a temperature issue. It's not normal for pure-digital circuits (Northbridge/Southbridge/CPU) to become "wobbly" with temp. On the Southbridge, the only problem I've heard of, is the RTC and CMOS RAM, the RAM may not function at reduced voltage (CMOS battery getting weak) and at some non-room temperature. Some of these conditions when they happened, were considered to be functional failures and the chipset should never have been shipped that way. Again, this is not a common condition, and there hasn't been a problem like that in yonks. Have you tried your one-stick-of-RAM test, in each of the four slots individually ? Don't forget to remove all power from the system, before moving the stick of RAM. That means switch off at the back or unplug the PC power cable, wait *at least* 30 seconds for 5VSB to drain. Asus motherboards all have a green LED onboard, that monitors +5VSB and when that LED extinguishes, then it's safe to move RAM. I don't know how many other brands have that. On some motherboards, there is the chicken-versus-egg problem, where the user needs to change BIOS versions, the board won't come up, and you can't flash the BIOS. Your board has a Dual BIOS, and by now, probably both sides have the same BIOS version. That would be another variable at this point. That's what the hope of using some other processor was about - getting the board to start by using an alternate processor, so the BIOS version could get changed when you wanted to change it. For removable BIOS chips, you could flash them using a lab programmer. But I no longer have access to stuff like that, and I don't know of any computer stores in town who I would expect to own such equipment. My newest motherboard here, has its own flasher onboard. You can change the BIOS version, *without* a CPU being in the CPU socket. There is a special USB port, you plug in a flash stick with a BIOS image on it, there's a pushbutton on the back of the PC, you press that, and a few minutes later, the machine has a new BIOS version. I've never used the feature, but the feature sure was attractive when I bought it. Because, it meant I "couldn't be held hostage by a motherboard refusal-to-start". There is a microcontroller next to the USB port, that reads the flash stick and writes the BIOS chip with what it finds. What used to cost $150, now costs a buck to do. Paul Thanks Paul, I messed around with temperature enough. The MOBO has been recycling in a hot room. The infrared thermometer allows me to do controlled but pointless experiments with a hairdryer. I have now taken some voltages. Where I removed a 470 uF 16V capacitor allows me to measure 12V rail. It goes up to 12V steady each cycle. The vacant PCI slot allows me to measure 5V again. Now it shows 0V, no 5V. No 5V explains the beep codes: Q: What do the beeps emitted during the POST mean? A: The following Award BIOS beep code descriptions may help you identify possible computer problems. (For reference only.) 1 short: System boots successfully 2 short: CMOS setting error 1 long, 1 short: Memory or motherboard error 1 long, 2 short: Monitor or graphics card error 1 long, 3 short: Keyboard error 1 long, 9 short: BIOS ROM error Continuous long beeps: Graphics card not inserted properly Continuous short beeps: Power error No 5V is a major power error. But why now? Let me elaborate. The infrared thermometer says there is no short circuit. The E4700 is cold. The literature says the maximum temperatures for the Intel P45 and the ICH10 I/O controller hub are well over 100 C. With a heat gun, I carefully raised the temperature of their heat sinks to 50C. Still no POST. End of silly experiment. There is no way the chips were damaged. I guess I need to find out why 5V is not delivered to rail. I'm an old man. I need to lie down and sleep. |
#13
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Getting there
Norm Why wrote:
Thanks Paul, I messed around with temperature enough. The MOBO has been recycling in a hot room. The infrared thermometer allows me to do controlled but pointless experiments with a hairdryer. I have now taken some voltages. Where I removed a 470 uF 16V capacitor allows me to measure 12V rail. It goes up to 12V steady each cycle. The vacant PCI slot allows me to measure 5V again. Now it shows 0V, no 5V. No 5V explains the beep codes: Q: What do the beeps emitted during the POST mean? A: The following Award BIOS beep code descriptions may help you identify possible computer problems. (For reference only.) 1 short: System boots successfully 2 short: CMOS setting error 1 long, 1 short: Memory or motherboard error 1 long, 2 short: Monitor or graphics card error 1 long, 3 short: Keyboard error 1 long, 9 short: BIOS ROM error Continuous long beeps: Graphics card not inserted properly Continuous short beeps: Power error No 5V is a major power error. But why now? Let me elaborate. The infrared thermometer says there is no short circuit. The E4700 is cold. The literature says the maximum temperatures for the Intel P45 and the ICH10 I/O controller hub are well over 100 C. With a heat gun, I carefully raised the temperature of their heat sinks to 50C. Still no POST. End of silly experiment. There is no way the chips were damaged. I guess I need to find out why 5V is not delivered to rail. I'm an old man. I need to lie down and sleep. Your board either has a 20 pin or a 24 pin "main" power connector. Place the ground of your multimeter on an I/O screw on the back panel. I like to clip the black probe to a screw, so I only need one hand to make measurements with the red probe. The ATX main power connector, you can probe in the back of the connector, and just barely touch the metal on each wire crimp in there. This allows every voltage on the connector to be verified. As long as an older power supply is used, it has nice colored wire and this makes it easier to determine which rail each wire is connected to. If you scroll down to 50% of this web page, there's a table of wire colors. http://www.playtool.com/pages/psucon...onnectors.html PWR_OK gray Pin 8 || || Pin 20 white -5 volts (optional) === "blank pin" You can see in that example, every wire has a color like gray or white or red or orange. And for the ATX supplies that adhere to the standard, this makes debugging a lot easier. I have a newer PSU with all-black wires and that's nothing but a pain in the ass. This kind of extension cable can be added to the power path, if you need some "wire colors" for inspiration. I might use something like this with my all-black-wire PSU, during a debug session. https://www.newegg.com/p/N82E16812198008 Paul |
#14
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Getting there
[snippage]
Q: What do the beeps emitted during the POST mean? A: The following Award BIOS beep code descriptions may help you identify possible computer problems. (For reference only.) 1 short: System boots successfully 2 short: CMOS setting error 1 long, 1 short: Memory or motherboard error 1 long, 2 short: Monitor or graphics card error 1 long, 3 short: Keyboard error 1 long, 9 short: BIOS ROM error Continuous long beeps: Graphics card not inserted properly Continuous short beeps: Power error No 5V is a major power error. But why now? Let me elaborate. The infrared thermometer says there is no short circuit. The E4700 is cold. The literature says the maximum temperatures for the Intel P45 and the ICH10 I/O controller hub are well over 100 C. With a heat gun, I carefully raised the temperature of their heat sinks to 50C. Still no POST. End of silly experiment. There is no way the chips were damaged. I guess I need to find out why 5V is not delivered to rail. I'm an old man. I need to lie down and sleep. Your board either has a 20 pin or a 24 pin "main" power connector. Place the ground of your multimeter on an I/O screw on the back panel. I like to clip the black probe to a screw, so I only need one hand to make measurements with the red probe. The ATX main power connector, you can probe in the back of the connector, and just barely touch the metal on each wire crimp in there. This allows every voltage on the connector to be verified. As long as an older power supply is used, it has nice colored wire and this makes it easier to determine which rail each wire is connected to. If you scroll down to 50% of this web page, there's a table of wire colors. http://www.playtool.com/pages/psucon...onnectors.html PWR_OK gray Pin 8 || || Pin 20 white -5 volts (optional) === "blank pin" You can see in that example, every wire has a color like gray or white or red or orange. And for the ATX supplies that adhere to the standard, this makes debugging a lot easier. I have a newer PSU with all-black wires and that's nothing but a pain in the ass. This kind of extension cable can be added to the power path, if you need some "wire colors" for inspiration. I might use something like this with my all-black-wire PSU, during a debug session. https://www.newegg.com/p/N82E16812198008 Paul Thanks for the valuable hardware info. I recall checking 5V when the Q9650 was plugged in. Even then 5V was unnatural. It would peak at 5V and then descend. Only boot 3 recycles, not infinite. |
#15
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Getting there
Norm Why wrote:
[snippage] Q: What do the beeps emitted during the POST mean? A: The following Award BIOS beep code descriptions may help you identify possible computer problems. (For reference only.) 1 short: System boots successfully 2 short: CMOS setting error 1 long, 1 short: Memory or motherboard error 1 long, 2 short: Monitor or graphics card error 1 long, 3 short: Keyboard error 1 long, 9 short: BIOS ROM error Continuous long beeps: Graphics card not inserted properly Continuous short beeps: Power error No 5V is a major power error. But why now? Let me elaborate. The infrared thermometer says there is no short circuit. The E4700 is cold. The literature says the maximum temperatures for the Intel P45 and the ICH10 I/O controller hub are well over 100 C. With a heat gun, I carefully raised the temperature of their heat sinks to 50C. Still no POST. End of silly experiment. There is no way the chips were damaged. I guess I need to find out why 5V is not delivered to rail. I'm an old man. I need to lie down and sleep. Your board either has a 20 pin or a 24 pin "main" power connector. Place the ground of your multimeter on an I/O screw on the back panel. I like to clip the black probe to a screw, so I only need one hand to make measurements with the red probe. The ATX main power connector, you can probe in the back of the connector, and just barely touch the metal on each wire crimp in there. This allows every voltage on the connector to be verified. As long as an older power supply is used, it has nice colored wire and this makes it easier to determine which rail each wire is connected to. If you scroll down to 50% of this web page, there's a table of wire colors. http://www.playtool.com/pages/psucon...onnectors.html PWR_OK gray Pin 8 || || Pin 20 white -5 volts (optional) === "blank pin" You can see in that example, every wire has a color like gray or white or red or orange. And for the ATX supplies that adhere to the standard, this makes debugging a lot easier. I have a newer PSU with all-black wires and that's nothing but a pain in the ass. This kind of extension cable can be added to the power path, if you need some "wire colors" for inspiration. I might use something like this with my all-black-wire PSU, during a debug session. https://www.newegg.com/p/N82E16812198008 Paul Thanks for the valuable hardware info. I recall checking 5V when the Q9650 was plugged in. Even then 5V was unnatural. It would peak at 5V and then descend. Only boot 3 recycles, not infinite. When you're watching the voltages of an ATX supply, keep in mind it has only one regulation loop, and a rail can be influenced by: 1) direct loading 2) cross loading Let's make up an example. If you're monitoring 5V and decide to draw 20 amps, maybe you see 4.9V from the PSU. That would be an example of direct loading. Now, instead, load the 12V rail with a 20A load, while monitoring the 5V. The 12V drops to 11.9V say. But the 5V rises to 5.1V. This is cross loading. The supply measures the mean of the 3.3V/5V/12V voltages and uses that value in the control loop. If something is getting loaded, the "whole PSU works harder". The loaded rail (12V in the cross load example), still demonstrates it "feels the load". The output has dropped to 11.9V. But because the "entire PSU is turned up", the 3.3V and 5V rails end up higher than they should be. The PSU design aims for no more than 5% cross load. Which is practically the whole range for regulation. The output transformer establishes outputs via turns ratio of the single output transformer. The high frequency transformer has winds for 3.3V, 5V, 12V. Due to the turns ratio, there is a very strong correlation between 3.3V, 5V, and 12V as a group. This is why a single control loop is sufficient to control it. Rectifiers are placed on each AC output of the three winds, giving DC voltages. Since the switching frequency is so high, relatively small electrolytic capacitors can give a reasonably smooth clean DC output. That is the description of a "traditional" 0.7PF 70% efficient power supply. I have several ATX PSUs in older computers that follow this description of behavior. For more info, see this hand-drawn schematic of a commercial PSU from slightly before 1999 perhaps. Don't quote everything this does verbatim, because some of what is in here, isn't exactly the way most are done. But it does illustrate the architecture a bit at least. And how cross-loading could be present, as a behavior. http://www.pavouk.org/hw/en_atxps.html More modern supplies have changed that a bit, and it affects the +5V behavior. Now, the architecture is called "double forward conversion", the conversion goes "120VAC to 12VDC", "12VDC to 3.3V/5V". There could be a cross loading effect between 3.3V and 5V, which sit on a separate SMPS regulator board. There should be less of an effect, between 12V loading and 5V output voltage. I might only have one supply here of that architecture, and I've never needed to measure any voltages on it, so can't provide any first hand experiences in terms of "wandering voltage values" with it. This is just a quick capsule summary of what you might see or expect from the primary DC voltages in the machine. Yes, the voltages do tell you things about what the machine is doing. In cases where the PSU is defective, sometimes the problem is obvious. As an example, my very first PSU from the 1999 year PC, it failed with "weakness". The supply still works today. However, the 12V rail will only power a 0.1 ampere fan. If you connect two fans to it, the voltage drops to around 6V or so. The supply cannot run a processor. You can't say the thing has "totally failed", but the supply is completely useless in any computer. It has a "strength problem". Visual examination of the inside of the supply, shows no leaking caps, and it's before the capacitor plague era, so that's not an expected failure for that one. I have other supplies that just conked out because their safety circuits detected trouble (internal overload). Supplies come in all shapes and sizes, some with rather bizarre designs inside and strange behaviors. There is the 200W Bestec that when it blows up, the 5V output rises to 9V, ruining hard drive, optical drive, and other stuff related to 5V rail. There aren't many other supplies that behave that badly, but it's not for a lack of trying. Paul |
#16
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Getting there
[snippage]
Place the ground of your multimeter on an I/O screw on the back panel. I like to clip the black probe to a screw, so I only need one hand to make measurements with the red probe. The ATX main power connector, you can probe in the back of the connector, and just barely touch the metal on each wire crimp in there. This allows every voltage on the connector to be verified. As long as an older power supply is used, it has nice colored wire and this makes it easier to determine which rail each wire is connected to. If you scroll down to 50% of this web page, there's a table of wire colors. http://www.playtool.com/pages/psucon...onnectors.html PWR_OK gray Pin 8 || || Pin 20 white -5 volts (optional) === "blank pin" You can see in that example, every wire has a color like gray or white or red or orange. And for the ATX supplies that adhere to the standard, this makes debugging a lot easier. I have a newer PSU with all-black wires and that's nothing but a pain in the ass. This kind of extension cable can be added to the power path, if you need some "wire colors" for inspiration. I might use something like this with my all-black-wire PSU, during a debug session. https://www.newegg.com/p/N82E16812198008 Paul Thanks for the valuable hardware info. I recall checking 5V when the Q9650 was plugged in. Even then 5V was unnatural. It would peak at 5V and then descend. Only boot 3 recycles, not infinite. When you're watching the voltages of an ATX supply, keep in mind it has only one regulation loop, and a rail can be influenced by: 1) direct loading 2) cross loading Let's make up an example. If you're monitoring 5V and decide to draw 20 amps, maybe you see 4.9V from the PSU. That would be an example of direct loading. Now, instead, load the 12V rail with a 20A load, while monitoring the 5V. The 12V drops to 11.9V say. But the 5V rises to 5.1V. This is cross loading. The supply measures the mean of the 3.3V/5V/12V voltages and uses that value in the control loop. If something is getting loaded, the "whole PSU works harder". The loaded rail (12V in the cross load example), still demonstrates it "feels the load". The output has dropped to 11.9V. But because the "entire PSU is turned up", the 3.3V and 5V rails end up higher than they should be. The PSU design aims for no more than 5% cross load. Which is practically the whole range for regulation. The output transformer establishes outputs via turns ratio of the single output transformer. The high frequency transformer has winds for 3.3V, 5V, 12V. Due to the turns ratio, there is a very strong correlation between 3.3V, 5V, and 12V as a group. This is why a single control loop is sufficient to control it. Rectifiers are placed on each AC output of the three winds, giving DC voltages. Since the switching frequency is so high, relatively small electrolytic capacitors can give a reasonably smooth clean DC output. That is the description of a "traditional" 0.7PF 70% efficient power supply. I have several ATX PSUs in older computers that follow this description of behavior. For more info, see this hand-drawn schematic of a commercial PSU from slightly before 1999 perhaps. Don't quote everything this does verbatim, because some of what is in here, isn't exactly the way most are done. But it does illustrate the architecture a bit at least. And how cross-loading could be present, as a behavior. http://www.pavouk.org/hw/en_atxps.html More modern supplies have changed that a bit, and it affects the +5V behavior. Now, the architecture is called "double forward conversion", the conversion goes "120VAC to 12VDC", "12VDC to 3.3V/5V". There could be a cross loading effect between 3.3V and 5V, which sit on a separate SMPS regulator board. There should be less of an effect, between 12V loading and 5V output voltage. I might only have one supply here of that architecture, and I've never needed to measure any voltages on it, so can't provide any first hand experiences in terms of "wandering voltage values" with it. This is just a quick capsule summary of what you might see or expect from the primary DC voltages in the machine. Yes, the voltages do tell you things about what the machine is doing. In cases where the PSU is defective, sometimes the problem is obvious. As an example, my very first PSU from the 1999 year PC, it failed with "weakness". The supply still works today. However, the 12V rail will only power a 0.1 ampere fan. If you connect two fans to it, the voltage drops to around 6V or so. The supply cannot run a processor. You can't say the thing has "totally failed", but the supply is completely useless in any computer. It has a "strength problem". Visual examination of the inside of the supply, shows no leaking caps, and it's before the capacitor plague era, so that's not an expected failure for that one. I have other supplies that just conked out because their safety circuits detected trouble (internal overload). Supplies come in all shapes and sizes, some with rather bizarre designs inside and strange behaviors. There is the 200W Bestec that when it blows up, the 5V output rises to 9V, ruining hard drive, optical drive, and other stuff related to 5V rail. There aren't many other supplies that behave that badly, but it's not for a lack of trying. Paul Thanks Paul. I found a pin on the 24-pin ATX power cable that gave steady 5V, each cycle. The MOBO would try to POST, give steady 5V, then shut down. Ad nauseam. I don't think the extension cable would give a fruitful line of inquiry. I looked into whether my eBay purchase was covered by money back guarantee, but the seller has gone out of business. I found two GA-EP45-DS3L boards for sale on eBay. The best looking offer is from the US, "factory refurbished" and fitted with an Intel E8400 CPU. I'll wait until the seller responds to my email and then possibly buy it? |
#17
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Getting there
[snippage]
Place the ground of your multimeter on an I/O screw on the back panel. I like to clip the black probe to a screw, so I only need one hand to make measurements with the red probe. The ATX main power connector, you can probe in the back of the connector, and just barely touch the metal on each wire crimp in there. This allows every voltage on the connector to be verified. As long as an older power supply is used, it has nice colored wire and this makes it easier to determine which rail each wire is connected to. If you scroll down to 50% of this web page, there's a table of wire colors. http://www.playtool.com/pages/psucon...onnectors.html PWR_OK gray Pin 8 || || Pin 20 white -5 volts (optional) === "blank pin" You can see in that example, every wire has a color like gray or white or red or orange. And for the ATX supplies that adhere to the standard, this makes debugging a lot easier. I have a newer PSU with all-black wires and that's nothing but a pain in the ass. This kind of extension cable can be added to the power path, if you need some "wire colors" for inspiration. I might use something like this with my all-black-wire PSU, during a debug session. https://www.newegg.com/p/N82E16812198008 Paul Thanks for the valuable hardware info. I recall checking 5V when the Q9650 was plugged in. Even then 5V was unnatural. It would peak at 5V and then descend. Only boot 3 recycles, not infinite. When you're watching the voltages of an ATX supply, keep in mind it has only one regulation loop, and a rail can be influenced by: 1) direct loading 2) cross loading Let's make up an example. If you're monitoring 5V and decide to draw 20 amps, maybe you see 4.9V from the PSU. That would be an example of direct loading. Now, instead, load the 12V rail with a 20A load, while monitoring the 5V. The 12V drops to 11.9V say. But the 5V rises to 5.1V. This is cross loading. The supply measures the mean of the 3.3V/5V/12V voltages and uses that value in the control loop. If something is getting loaded, the "whole PSU works harder". The loaded rail (12V in the cross load example), still demonstrates it "feels the load". The output has dropped to 11.9V. But because the "entire PSU is turned up", the 3.3V and 5V rails end up higher than they should be. The PSU design aims for no more than 5% cross load. Which is practically the whole range for regulation. The output transformer establishes outputs via turns ratio of the single output transformer. The high frequency transformer has winds for 3.3V, 5V, 12V. Due to the turns ratio, there is a very strong correlation between 3.3V, 5V, and 12V as a group. This is why a single control loop is sufficient to control it. Rectifiers are placed on each AC output of the three winds, giving DC voltages. Since the switching frequency is so high, relatively small electrolytic capacitors can give a reasonably smooth clean DC output. That is the description of a "traditional" 0.7PF 70% efficient power supply. I have several ATX PSUs in older computers that follow this description of behavior. For more info, see this hand-drawn schematic of a commercial PSU from slightly before 1999 perhaps. Don't quote everything this does verbatim, because some of what is in here, isn't exactly the way most are done. But it does illustrate the architecture a bit at least. And how cross-loading could be present, as a behavior. http://www.pavouk.org/hw/en_atxps.html More modern supplies have changed that a bit, and it affects the +5V behavior. Now, the architecture is called "double forward conversion", the conversion goes "120VAC to 12VDC", "12VDC to 3.3V/5V". There could be a cross loading effect between 3.3V and 5V, which sit on a separate SMPS regulator board. There should be less of an effect, between 12V loading and 5V output voltage. I might only have one supply here of that architecture, and I've never needed to measure any voltages on it, so can't provide any first hand experiences in terms of "wandering voltage values" with it. This is just a quick capsule summary of what you might see or expect from the primary DC voltages in the machine. Yes, the voltages do tell you things about what the machine is doing. In cases where the PSU is defective, sometimes the problem is obvious. As an example, my very first PSU from the 1999 year PC, it failed with "weakness". The supply still works today. However, the 12V rail will only power a 0.1 ampere fan. If you connect two fans to it, the voltage drops to around 6V or so. The supply cannot run a processor. You can't say the thing has "totally failed", but the supply is completely useless in any computer. It has a "strength problem". Visual examination of the inside of the supply, shows no leaking caps, and it's before the capacitor plague era, so that's not an expected failure for that one. I have other supplies that just conked out because their safety circuits detected trouble (internal overload). Supplies come in all shapes and sizes, some with rather bizarre designs inside and strange behaviors. There is the 200W Bestec that when it blows up, the 5V output rises to 9V, ruining hard drive, optical drive, and other stuff related to 5V rail. There aren't many other supplies that behave that badly, but it's not for a lack of trying. Paul Thanks Paul. I found a pin on the 24-pin ATX power cable that gave steady 5V, each cycle. The MOBO would try to POST, give steady 5V, then shut down. Ad nauseam. I don't think the extension cable would give a fruitful line of inquiry. I looked into whether my eBay purchase was covered by money back guarantee, but the seller has gone out of business. I found two GA-EP45-DS3L boards for sale on eBay. The best looking offer is from the US, "factory refurbished" and fitted with an Intel E8400 CPU. I'll wait until the seller responds to my email and then possibly buy it? Update from seller. Not "factory refurbished". Pulled out of father's computer, still working. Hence same condition as one form China. From USA, eBay guarantee should work. |
#18
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Getting there
Norm Why wrote:
[snippage] Place the ground of your multimeter on an I/O screw on the back panel. I like to clip the black probe to a screw, so I only need one hand to make measurements with the red probe. The ATX main power connector, you can probe in the back of the connector, and just barely touch the metal on each wire crimp in there. This allows every voltage on the connector to be verified. As long as an older power supply is used, it has nice colored wire and this makes it easier to determine which rail each wire is connected to. If you scroll down to 50% of this web page, there's a table of wire colors. http://www.playtool.com/pages/psucon...onnectors.html PWR_OK gray Pin 8 || || Pin 20 white -5 volts (optional) === "blank pin" You can see in that example, every wire has a color like gray or white or red or orange. And for the ATX supplies that adhere to the standard, this makes debugging a lot easier. I have a newer PSU with all-black wires and that's nothing but a pain in the ass. This kind of extension cable can be added to the power path, if you need some "wire colors" for inspiration. I might use something like this with my all-black-wire PSU, during a debug session. https://www.newegg.com/p/N82E16812198008 Paul Thanks for the valuable hardware info. I recall checking 5V when the Q9650 was plugged in. Even then 5V was unnatural. It would peak at 5V and then descend. Only boot 3 recycles, not infinite. When you're watching the voltages of an ATX supply, keep in mind it has only one regulation loop, and a rail can be influenced by: 1) direct loading 2) cross loading Let's make up an example. If you're monitoring 5V and decide to draw 20 amps, maybe you see 4.9V from the PSU. That would be an example of direct loading. Now, instead, load the 12V rail with a 20A load, while monitoring the 5V. The 12V drops to 11.9V say. But the 5V rises to 5.1V. This is cross loading. The supply measures the mean of the 3.3V/5V/12V voltages and uses that value in the control loop. If something is getting loaded, the "whole PSU works harder". The loaded rail (12V in the cross load example), still demonstrates it "feels the load". The output has dropped to 11.9V. But because the "entire PSU is turned up", the 3.3V and 5V rails end up higher than they should be. The PSU design aims for no more than 5% cross load. Which is practically the whole range for regulation. The output transformer establishes outputs via turns ratio of the single output transformer. The high frequency transformer has winds for 3.3V, 5V, 12V. Due to the turns ratio, there is a very strong correlation between 3.3V, 5V, and 12V as a group. This is why a single control loop is sufficient to control it. Rectifiers are placed on each AC output of the three winds, giving DC voltages. Since the switching frequency is so high, relatively small electrolytic capacitors can give a reasonably smooth clean DC output. That is the description of a "traditional" 0.7PF 70% efficient power supply. I have several ATX PSUs in older computers that follow this description of behavior. For more info, see this hand-drawn schematic of a commercial PSU from slightly before 1999 perhaps. Don't quote everything this does verbatim, because some of what is in here, isn't exactly the way most are done. But it does illustrate the architecture a bit at least. And how cross-loading could be present, as a behavior. http://www.pavouk.org/hw/en_atxps.html More modern supplies have changed that a bit, and it affects the +5V behavior. Now, the architecture is called "double forward conversion", the conversion goes "120VAC to 12VDC", "12VDC to 3.3V/5V". There could be a cross loading effect between 3.3V and 5V, which sit on a separate SMPS regulator board. There should be less of an effect, between 12V loading and 5V output voltage. I might only have one supply here of that architecture, and I've never needed to measure any voltages on it, so can't provide any first hand experiences in terms of "wandering voltage values" with it. This is just a quick capsule summary of what you might see or expect from the primary DC voltages in the machine. Yes, the voltages do tell you things about what the machine is doing. In cases where the PSU is defective, sometimes the problem is obvious. As an example, my very first PSU from the 1999 year PC, it failed with "weakness". The supply still works today. However, the 12V rail will only power a 0.1 ampere fan. If you connect two fans to it, the voltage drops to around 6V or so. The supply cannot run a processor. You can't say the thing has "totally failed", but the supply is completely useless in any computer. It has a "strength problem". Visual examination of the inside of the supply, shows no leaking caps, and it's before the capacitor plague era, so that's not an expected failure for that one. I have other supplies that just conked out because their safety circuits detected trouble (internal overload). Supplies come in all shapes and sizes, some with rather bizarre designs inside and strange behaviors. There is the 200W Bestec that when it blows up, the 5V output rises to 9V, ruining hard drive, optical drive, and other stuff related to 5V rail. There aren't many other supplies that behave that badly, but it's not for a lack of trying. Paul Thanks Paul. I found a pin on the 24-pin ATX power cable that gave steady 5V, each cycle. The MOBO would try to POST, give steady 5V, then shut down. Ad nauseam. I don't think the extension cable would give a fruitful line of inquiry. I looked into whether my eBay purchase was covered by money back guarantee, but the seller has gone out of business. I found two GA-EP45-DS3L boards for sale on eBay. The best looking offer is from the US, "factory refurbished" and fitted with an Intel E8400 CPU. I'll wait until the seller responds to my email and then possibly buy it? Update from seller. Not "factory refurbished". Pulled out of father's computer, still working. Hence same condition as one form China. From USA, eBay guarantee should work. With the E8400 in it, you'd at least have a known-working config to go back to. If and when you get that, check the BIOS version just to see how it compares to the other one. Paul |
#19
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Getting there
[snippage]
I should've checked the CMOS battery first. But when I checked it was dead so I replaced it with a good one. Now the system no longer responds to keyboard like it did at first. Beep speaker give single beep, OK. System shuts down unexpectantly after five seconds. This means CMOS needs tweaking. Currently running with 500 MB RAM module and Q8400 CPU. Later. Do you have the heatsink/fan on the CPU ? Is the cable from the heatsink/fan plugged into the *CPU* header ? The BIOS expects to find the pulsations of the RPM signal from the CPU fan, on the CPU header pins. Failure to provide pulsations on the third yellow wire, will result in the BIOS doing a safety shutdown. No other fan header has such a requirement. Whether it's a three wire or four wire fan, plug it into the CPU header. Make sure the fan spins at powerup. If the header has three pins, and the fan has four wires, it can still work as long as pin1 goes to pin1. The user manual will typically label the pins, black is ground, red might be +12V, yellow could be the RPM (2ppr) signal. The fan pulses twice per revolution, due to the way the brushless design, the permanent magnets and the hall probe for mag field work. Paul Yes and yes. The problem seems to be that the BIOS program does not respond to my PS/2 keyboard. I have BT keyboard and mouse. That seems a goofy idea. I have a USB mouse but no USB keyboard. I suppose device selection can be done in BIOS program. Once the BIOS program decides nothing is happening the PC shuts down. I sent a message to seller. The PS/2 connections go through the IO shield to the mainboard. It is independent of any connections to MX300-X gaming case. |
#20
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Getting there
Do you have the heatsink/fan on the CPU ? Is the cable from the heatsink/fan plugged into the *CPU* header ? The BIOS expects to find the pulsations of the RPM signal from the CPU fan, on the CPU header pins. Failure to provide pulsations on the third yellow wire, will result in the BIOS doing a safety shutdown. No other fan header has such a requirement. Whether it's a three wire or four wire fan, plug it into the CPU header. Make sure the fan spins at powerup. If the header has three pins, and the fan has four wires, it can still work as long as pin1 goes to pin1. The user manual will typically label the pins, black is ground, red might be +12V, yellow could be the RPM (2ppr) signal. The fan pulses twice per revolution, due to the way the brushless design, the permanent magnets and the hall probe for mag field work. Paul Yes and yes. The problem seems to be that the BIOS program does not respond to my PS/2 keyboard. I have BT keyboard and mouse. That seems a goofy idea. I have a USB mouse but no USB keyboard. I suppose device selection can be done in BIOS program. Once the BIOS program decides nothing is happening the PC shuts down. I sent a message to seller. The PS/2 connections go through the IO shield to the mainboard. It is independent of any connections to MX300-X gaming case. My bad. I had one stick 500 MB RAM installed. I removed that and installed two 4GB RAM sticks in dual channel configuration. Now keyboard and BIOS program work. |
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