repair and troubleshoot atx power supply 435 W

[senz_90]

anyone could u mind to help me fix this power supply please?

i have 2 power supply like this specified and i just try to fix it after have a time. maybe u can tell me to buy a new cheap one. but i just wanna make a training for myself because that PS looks like a challenge for me, i haved repaired the other 2 piece PS before. and the problem just a bulked caps so it's not a very hard of course.
i just think that power supply can be used again with this problem that is not very bad i think
1. one PS have a voltage in rail likes 12v, 5v but the problem is I get a little electric shock when i touch the probe meter to measure volts, of course that is a problem so my PC can't turn on when i use that. i can't figure out the problem.
2. for the second one there is almost have'nt any voltage in rail. i just try to open it and like the other's guide maybe the power transistor, mosfet, or diode schottkhy have a problem, i try to use my AVOmeter test that, the transistor and diode looks like no problem, Mosfet is the one I don't know to to test it. so i can't tell you that is fine or defective.. this photo below is the second one power supply..


So anyone could help me what is the problem with my PS? for note i have already test filter capacitor and mains filter capacitor 200v with my homemade ESR meter, every caps looks like fine and have a low ESR and didn't have a bulked, leakage view of course.. i think the problem maybe the IC 2005Z on this photo, but it just a predict. my fuse looks fine when i tested it. no sign likes burns, or stinky smell.

any advice or guide to test the predicted defectice component is really helpful..

[Th3_uN1Qu3]

Re: repair and troubleshoot atx power supply 435 W

On the first PSU replace the Y caps which are most likely failed and leaky, and dangerous. They are on the primary side from line to earth and neutral to earth. Also make sure you are using a properly grounded outlet.

On the second one, what do you mean by "almost haven't any voltage?" Numbers please.

By the way, your photo does not show.

[senz_90]

Re: repair and troubleshoot atx power supply 435 W

On the first PSU replace the Y caps which are most likely failed and leaky, and dangerous. They are on the primary side from line to earth and neutral to earth. Also make sure you are using a properly grounded outlet.

On the second one, what do you mean by "almost haven't any voltage?" Numbers please.

By the way, your photo does not show.

first at all, thanks replying

Y caps is caps means filtering mains current? it has 2 caps that i tested good with my homemade esr meter. but i'll try your advice.. i have a unused caps on my store box.. sorry i think that my upload success. and sorry for late replying bcoz busy on my college. haha..

i means that it hasn't voltage when i measure it. just 5v on standby mode. the others no voltage absolutely... is there any advice?

[lti]

Re: repair and troubleshoot atx power supply 435 W

The Y caps are the two blue ceramic caps in the corner.

[Behemot]

Re: repair and troubleshoot atx power supply 435 W

Y are usually the blue ceramic caps which should be safety certified as Y caps but they often use cheap uncertified ones in this crappy PSUs.

As Th3_uN1Qu3 suggested, check that you have good ground in your plug (aluminium conductors for example get loose quite often in the plug and you need to tighten them). I would also add to check the grounding inside the PSU. The earth wire (middle pin) should be connected tightly to the casing.

EDIT: lti, you pay the

[Escort Eagle]

Re: repair and troubleshoot atx power supply 435 W

For the Second Power Supply - If you get +5VSB and Both C13007 in Primary Side are OK then, --> Check those Switching Transistors (C945 or C1815) and Crystal Diodes (1N4148) Which I have shown in the Image . May be one of them or Both transistors (C945 or C1815) or Crystal Diodes (1N4148) are faulty .

For First Power supply - one of the Capacitor or Diodes or Y capacitors is leaky . But it is very difficult to find the Faulty one !!! I think you should leave this First one otherwise it will crack your brain !!

[senz_90]

Re: repair and troubleshoot atx power supply 435 W

The Y caps are the two blue ceramic caps in the corner.

thanks the advice.. i'm gonna change it and maybe it fixed my problem issue..

Y are usually the blue ceramic caps which should be safety certified as Y caps but they often use cheap uncertified ones in this crappy PSUs.

As Th3_uN1Qu3 suggested, check that you have good ground in your plug (aluminium conductors for example get loose quite often in the plug and you need to tighten them). I would also add to check the grounding inside the PSU. The earth wire (middle pin) should be connected tightly to the casing.

yes.. i have the same predicted but i feel i tighten all ground plug already.. maybe the problem is the Y caps.. im gonna change it.. thank you

For the Second Power Supply - If you get +5VSB and Both C13007 in Primary Side are OK then, --> Check those Switching Transistors (C945 or C1815) and Crystal Diodes (1N4148) Which I have shown in the Image . May be one of them or Both transistors (C945 or C1815) or Crystal Diodes (1N4148) are faulty .

For First Power supply - one of the Capacitor or Diodes or Y capacitors is leaky . But it is very difficult to find the Faulty one !!! I think you should leave this First one otherwise it will crack your brain !!

i haved checked already that i feel.. but i wanna check it again by your advice. maybe i made a mistake reading on the result..after i checked it and maybe found defective one's, what could the next step maybe i have to go after change the defective one's and got no result sir?

[Pentium4]

Re: repair and troubleshoot atx power supply 435 W

Did you check the diode that you pulled that was just to the left of the 5VSB transformer? (Probably SB540 or SB560) Also check the little 50V caps in that area (and the two by the feedback transformer), seen YC caps dry out and die

[Escort Eagle]

Re: repair and troubleshoot atx power supply 435 W

i haved checked already that i feel ............................ after change the defective one's and got no result sir?

First tell us, what is the result ?

[Escort Eagle]

Re: repair and troubleshoot atx power supply 435 W

If the both Transistors and Crystal Diodes are OK, Then change ---

1. Those both 2.7K Resistors. If you don't find 2.7K Resistor in the market, then you can Replace it with 2.2K or 3.3K (1/4W) . (Shown in the Image)

And Change -

2. Those both 10μF/50V Capacitors also . (Shown in the Image)

And let us know what is the result ......

[senz_90]

Re: repair and troubleshoot atx power supply 435 W

Did you check the diode that you pulled that was just to the left of the 5VSB transformer? (Probably SB540 or SB560) Also check the little 50V caps in that area (and the two by the feedback transformer), seen YC caps dry out and die

did you mean schottsky diode on the heat sink sir? component on the heat sink is already checked likes i said in the early posted.. but just the one mosfet i still no confidence to say it is defective or not because i don't know the way checked mosfet with my cheapy analog VOM.. the other's has good result and i just checked it good..YC caps where it is exactly?

for note : i have already change two blue Y caps on the corner (472, 1Kv) that suggested from the other's kind and tighten ground cable in mid of mains socket to the case already. but it is still got me electric shock

If the both Transistors and Crystal Diodes are OK, Then change ---

1. Those both 2.7K Resistors. If you don't find 2.7K Resistor in the market, then you can Replace it with 2.2K or 3.3K (1/4W) . (Shown in the Image)

And Change -

2. Those both 10μF/50V Capacitors also . (Shown in the Image)

And let us know what is the result ......

hmm.. i don't checked the transistor and diode already, but i have already change the Y caps because i thought that lead me to good result..but it is still got me electric shock.. there is exactly another defective must to change !! I think this night i wanna make it clear.. to check all about you suggest sir.. this night gonna be a long long night of course i'll be as soon as give you the result..

[Pentium4]

Re: repair and troubleshoot atx power supply 435 W

I attached a picture of the diode i was referring to.

Are the blue Y caps you used safety certified?

It looks like all the electrolyitcs are YC, I would check all of those small capacitors probably ranging from 1uF, 2.2uF, 4.7uF, 10uF, 22uF, 47uF all rated at 50V

[senz_90]

Re: repair and troubleshoot atx power supply 435 W

If the both Transistors and Crystal Diodes are OK, Then change ---

1. Those both 2.7K Resistors. If you don't find 2.7K Resistor in the market, then you can Replace it with 2.2K or 3.3K (1/4W) . (Shown in the Image)

And Change -

2. Those both 10μF/50V Capacitors also . (Shown in the Image)

And let us know what is the result ......

the resistor, transistor is fine and diode also..both capacitors value 2.2μF/50V in my case (not 10μF/50V) like the one u point me on photo to check also fine.. so i didn't change anything.. just the Y caps.. what is the next step that i have to check the component sir??

I attached a picture of the diode i was referring to.

Are the blue Y caps you used safety certified?

It looks like all the electrolyitcs are YC, I would check all of those small capacitors probably ranging from 1uF, 2.2uF, 4.7uF, 10uF, 22uF, 47uF all rated at 50V

i think that is worth enough caps.. i have checked all small caps with my esr meter and didn't found defective one's.. the diode that u suggest to check is fine.. it has a two legs right (in my case SB560)? i just checked it like usual check diode method and no defective... what is the problem exactly i have?
i think i have to upload my changed capacitor and hear ur opinion about that.. as soon as i will give u the photo sir..

[Escort Eagle]

Re: repair and troubleshoot atx power supply 435 W

May be I was talking about your Second Power Supply which was not totally running . But how does "Y Caps" drop in the middle !!! Let me clear one thing - Which Picture you have uploaded here - are they of Second Power supply (Which was not totally running) OR first Power Supply (Which gives shock at 5V) ??

[Pentium4]

Re: repair and troubleshoot atx power supply 435 W

It is definitely a little easier to make separate threads for two different PSU's. How high was the ESR on those little caps?

[senz_90]

Re: repair and troubleshoot atx power supply 435 W

May be I was talking about your Second Power Supply which was not totally running . But how does "Y Caps" drop in the middle !!! Let me clear one thing - Which Picture you have uploaded here - are they of Second Power supply (Which was not totally running) OR first Power Supply (Which gives shock at 5V) ??

ahh.. i forget one thing. please forgive my stupidness. the second one is now run like the first one. have a normal voltage each rails. but a little electric shock too. the picture is the second one but i mean the other one that has not totally running. so stupid me forget to upload the third one that i means.. maybe it must be a different thread because the third one has different type specs..

[senz_90]

Re: repair and troubleshoot atx power supply 435 W

It is definitely a little easier to make separate threads for two different PSU's. How high was the ESR on those little caps?

it has a low esr between 1-3.5 ohms that reading on my esr.. yeah. i made mistake that gonna be makes someone blames me..really sorry for that..is that normal reading for a small value caps 1uf to 47uf caps sir?
i must makes different thread now..

[Th3_uN1Qu3]

Re: repair and troubleshoot atx power supply 435 W

Yes that reading is fine for low value caps. For electrolytic caps <100uF, capacitance reading is more important than ESR.

[Pentium4]

Re: repair and troubleshoot atx power supply 435 W

A little off topic. When would you say the ESR for these low value caps starts to become a problem? I replace any that are 8 ohms or higher because that just tells me that if it hasn't failed yet, it is failing and will cause problems soon.

[Escort Eagle]

Re: repair and troubleshoot atx power supply 435 W

haaaaah...... !!! You are really crazy man !!! Continuously I was suggesting for that third non-running Power supply and you are applying it to running power supply .... huh ... lol !!!

If your both power supply is shocking a little - that means - You have a poor Ground Source . Make a Good Ground Source - I think your problem will be solve . I don't understand, what is the problem if PSU gives little shock, PC can run fine with that little shock . Because every PSU gives a little shock .

Probably Solution For Shock - Every rail +12V, +5V, +3.3V and +5VSB has their Discharging Resistors . Look at each rail you will find 10 Ω to 100 Ω and they are 1/2W to 2W Discharging Resistor Connected in each rail . Change those Discharging Resistors . I know they are measuring good . But they are not working well-enough as a new one . So, Change them without any question . I hope your problem will be solved . If your problem do not solve by changing Discharging resistors, then you have no other option left to solve that .

And Make a different Post with your Third PSU which does not run at all .