Help, my comp is dying or dead

[tw]

Originally Posted by glatt

tw, you have posted about power supplies in the past. Can you link to a power supply that you would buy, and explain what it has that makes it different?

Too many power supply manufacturers (hundreds if not thousands) meaning too much time to assemble a list. However basic market techniques used to buy anything technical also apply to a power supply.

First, market retail price makes obvious supplies that are missing essential functions. Minimum sufficient supplies are about $60 full retail (not to be confused with discounted prices for that same model). That does not even imply a $100 supply is sufficient as one might assume using binary logic.

Second, a manufacturer provides a long list of numeric spec. A manufacturer dumping an inferior product will not provide those specs so that the 1% who actually know technology cannot 'blow the whistle'. What constitutes numeric specs for a power supply? So many numbers as to fill a page. Some of those manufacturer numbers that must exist in writing would include:
Short circuit protection on all outputs (short all outputs together and still power supply will never fail)
Over voltage protection (power supply will never damage any other computer components)
Over power protection (too many computer components never causes damage to a supply)
EMI/RFI compliance for CE, CISPR22, FCC part 15 (ie put an AM (medium wave) radio next to computer and have no interference)
Safety compliance for VDE, TUV, D, N, S, Fi, UL, C, UL, CB
Full load hold up time (how long power supply works just fine with no AC power input): 16msec.
Efficiency greater than 65% (power supplies should exceed this number although conservatively rated supplies may only list this number)
Ripple or noise 1%
MTBF under full load at 25°C >100k hrs
Acoustics noise listed in dB while under full load.

Third, only useful power supply reviews always do tests such as loading the power supply to 100% rated power and measure its voltages. Also short all power supply outputs and demonstrate no failure. Tom's Hardware was one of so few web sites that performed such tests. Most reviews are so technically pathetic as to discuss appearance, weight, and some implied convenience.

Fourth, recommendations from many computer techs often mean nothing. To be A+ Certified, a computer tech need not even know how electricity works. Too many techs will push irrelevant numbers such as total wattage and will also hype more fans.

Even better supplies are also universal. These are features beyond minimal requirements. For example, a 120 volt power supply works just fine when AC voltage is at 90 volts or rises to 265 volts - just like all laptops. Many supplies that do this will claim a minimum voltage of 100 VAC or less. Such 120 VAC supplies will often work even at 85 VAC.

Even better supplies also include power factor correction which means its AC power interface is even more robust as well as more efficient.

Some manufacturers are often listed repeatedly for their superior designs including Antec, Computer Power & Cooling, and Seasonic. That does not mean every supply from these companies are best. But as noted previously, no supply observed in CompUSA appeared to be minimally acceptable. Dumped supplies into an American market flooded with technically naive computer assemblers is so profitable.

A quickest identifier of a defective supply is the AM (medium wave) radio test. If a power supply interferes with reception, then the power supply probably has multiple severe deficiencies.

Move on to wattage. Total wattage says little useful. For example a Dell 300 watt power supply might be rated as 430 watts by a clone manufacturer. Neither watt number is a lie. But many computer assemblers would not understand why those two numbers accurately measure the same supply.

More important are output amperage for each voltage. Unfortunately, no one can accurately say what the actual load will be or if that power supply is actually performing properly. A fully assembled computer with all peripherals accessed simultaneously has output voltages measure using a multimeter. If building a computer, there is no way around confirming hardware with measured numbers. If the computer has a motherboard voltage monitor, that motherboard function also must be calibrated with the meter.

None of this is complex. Most of this takes longer to read here than to actually perform - except if a power supply manufacturer makes doing this difficult.