If my power supply goes bad, is it a good idea to go down to my local CompUSA store and buy a replacement? Here is a "used" CompUSA 250 watt ATX power supply which I have recently acquired.
Looks like lots of bulging capacitors. So I applied power to see what the 5vsb was doing. It came up a little over 5 volts. Good start, but thought I would change the bulging output capacitors before proceeding. All were Rulycon brand. Here is what I found:
2200 uF/10V 1.5 (esr)
2200 uF/10V 2.0
2200 uF/10V 1.7
1000 uF/16V 2.8
1000 uF/16V 3.5
470 uF/16V 8.6
1000 uF/10V 4.4 (5vsb filter)
Since ALL of these output capacitors were obviously bad, do you think the non-bulging smaller caps are bad (same brand)? I thought Fuhjyyu were the worst brand of capacitors, but I have never seen a psu where ALL of the capacitors were bad.
Main pwm chip is AP3843B and supervisor chip is marked Bestec B850. 5vsb switching transistors are K3067 and C945, common 2 transistor 5vsb circuit. Marking on 5vsb transformer is LP6100D. With no model number or OEM label, I wonder who made this psu....L&C, Bestec, or .........???
With output caps replaced, power came up fine as follows:
12V 12.03V
5V 5.25V
3.3V 3.38V
5vsb 5.02V
However, as I was monitoring and watching the 12 volt rail, the voltage varied from 12.02V to 12.73V, back and forth for a while. Finally seems to have settled at 12.03V. Maybe those little caps need replacement too!
The 12V and 5V output rails have PI filters, but the 3.3V looks somewhat lacking.
The QC label indicates this psu was manufactured July 2001. Overall, I would not have trusted it as a replacement. Would you?
Looks like lots of bulging capacitors. So I applied power to see what the 5vsb was doing. It came up a little over 5 volts. Good start, but thought I would change the bulging output capacitors before proceeding. All were Rulycon brand. Here is what I found:
2200 uF/10V 1.5 (esr)
2200 uF/10V 2.0
2200 uF/10V 1.7
1000 uF/16V 2.8
1000 uF/16V 3.5
470 uF/16V 8.6
1000 uF/10V 4.4 (5vsb filter)
Since ALL of these output capacitors were obviously bad, do you think the non-bulging smaller caps are bad (same brand)? I thought Fuhjyyu were the worst brand of capacitors, but I have never seen a psu where ALL of the capacitors were bad.
Main pwm chip is AP3843B and supervisor chip is marked Bestec B850. 5vsb switching transistors are K3067 and C945, common 2 transistor 5vsb circuit. Marking on 5vsb transformer is LP6100D. With no model number or OEM label, I wonder who made this psu....L&C, Bestec, or .........???
With output caps replaced, power came up fine as follows:
12V 12.03V
5V 5.25V
3.3V 3.38V
5vsb 5.02V
However, as I was monitoring and watching the 12 volt rail, the voltage varied from 12.02V to 12.73V, back and forth for a while. Finally seems to have settled at 12.03V. Maybe those little caps need replacement too!
The 12V and 5V output rails have PI filters, but the 3.3V looks somewhat lacking.
The QC label indicates this psu was manufactured July 2001. Overall, I would not have trusted it as a replacement. Would you?
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