Ultra Power Supply

[Sparkie54]

Can someone please help me with repairing a PC power supply. My supply quit and I have been only partially successful. I found a burned out resistor on the board I replaced > a 5 watt 20 ohm and a bulging cap that I also replaced. When I try to power up now with the supply hooked up to a working pc the motherboard lights come on and I get a momentary turning of the fans and then it stops. The board lights still stay on and about every 15 to 30 seconds the fans again do a momentary spin and then stop. I tried to do some power test with a volt meter and did not have any power form the 12 volt rail and from the 5 volt rail I get about .02 volts. I did not test for the 3 volt rail though. I do not have a working knowledge of electronics but can do some minor test with a mulit meter and replace diods capacitors and resistors and such. Any help would be appreciated

Thanks Sparkie54

[sillyboy]

um, why are you trying to repair it? last time i checked power supplies were pretty cheap. based on the behaviour you have explained, i reckon your fixes to the broken components are fine, but not right. i think the power supply is shutting itself down because it is running past some threshold.

[Sparkie54]

um, why are you trying to repair it? last time i checked power supplies were pretty cheap. based on the behaviour you have explained, i reckon your fixes to the broken components are fine, but not right. i think the power supply is shutting itself down because it is running past some threshold.

thank you for your response : I understand that taking time to fix a power supply is not cost effective but I wanted to learn a bit about electronics and a power supply is a lot less complicated than other components of a computer. I am a custom pc builder but a mechanic by trade and computers have become my hobby. I have built two custom PC's with Ultra power supplies and understand that this model Ultra in question is a poor design. Guess I will just toss it and move on. Thanks again Sparkie54

[caperjack]

thank you for your response : I understand that taking time to fix a power supply is not cost effective but I wanted to learn a bit about electronics and a power supply is a lot less complicated than other components of a computer. I am a custom pc builder but a mechanic by trade and computers have become my hobby. I have built two custom PC's with Ultra power supplies and understand that this model Ultra in question is a poor design. Guess I will just toss it and move on. Thanks again Sparkie54

are you aware that its dangerous and a risk of shock to open and work within a power a supply

[caperjack]

thank you for your response : I understand that taking time to fix a power supply is not cost effective but I wanted to learn a bit about electronics and a power supply is a lot less complicated than other components of a computer. I am a custom pc builder but a mechanic by trade and computers have become my hobby. I have built two custom PC's with Ultra power supplies and understand that this model Ultra in question is a poor design. Guess I will just toss it and move on. Thanks again Sparkie54

are you aware that its dangerous and a risk of shock to open and work within a power a supply ,as it hold power after its unplugged

[Sparkie54]

are you aware that its dangerous and a risk of shock to open and work within a power a supply

Yes I am aware of the dangers of a power supply thanks for being concerned. My background is aircraft maintenance and I guess it is fair to say I have tinkered with a few things that can be harmful. With computers being a passion / hobby and having built a few from scratch I thought I would try my luck at the power supply. Sure would be cheaper and easier to just buy a new power supply but for me well that would be throwing in the towel. I have always enjoyed figuring out what makes something tick and what I have found out about power supplies is that in some respects they are simple and others quite advanced. With time and patience I will hopefully fix this one and feel like I have accomplished something.

[caperjack]

With time and patience I will hopefully fix this one and feel like I have accomplished something.

And that the way it should be ,for me i remove the fan and throw them away ,for that all i know,and i know my limits!

[thepastimer]

I noticed that there are two threads with the same name, but it seems this is the one to post on. Have you tested the inverter? (that switches from AC to DC)