Problem with ATX 450W PSU

[shovenose]

Have you verfied that there is no short anywhere?

[Galib]

Sorry, you didn't mention that you tested the ICs in your last POST. How are you testing them?

Man !! Why will I stock the Bad IC ?? IC testing is not sky rocking Hard !! It is very simple . If you have an extra power supply, then Put there two IC Base - One for TL494 - it will be 16 DIP and Another for LM339 - it will be 14 DIP for Permanently . If you get any TL494 or KA7500B or LM339 from non-working power supply, then just put the IC to that good Power supply's correct IC Base and then Just Run the power supply . If the Power supply runs then IC is GOOD, If not then the IC is BAD . If it is good then stock to your collection, otherwise throw it ........ !!! Is it so sky rocking Hard ....... !?!?

Have you verfied that there is no short anywhere?

No Shovenose, there is no short circuit .

[c_hegge]

@Galib, could we have a picture of the internals?

I wasn't trying to say in my last post that parts are hard to test, but some people still get it wrong.

[Galib]

Hi,
I was extremely busy with repairing of power supply . Good news is that I have repaired 6 power supplies and today delivered them .

Why do you want picture of power supply ? What can you understand with that !!!!!!!! I think you may be looking for Bad Capacitor . But for your kind information - All Caps are absolutely Fine . They have not any bulge and they are looking young sexy !!!!!!! All the Power supply made by China and everyone is familiar with China made power supply .

Currently I am facing problem with two power supplies - One is not switching . I am not getting switching voltage . I have checked all the resistor, Diode, Capacitor and everything in the controller section but no one has any problem .

Another - It is Switching but Power supply is not running . I have checked all things in 13007 Primary high voltage section and Output section . Everything is OK . But the Power supply is not running .

[c_hegge]

I wasn't just looking for bad caps. I was more interested in what sort of design and what components we're dealing with. Exactly what can go wrong can vary from unit to unit.

[Galib]

Sorry!! My mobile Camera's Resolution is not good !!

1(A,B,C) is for one power supply which is not switching . And 2(A,B,C) is for another power supply which is switching but not running .

Here mentioned that - I have removed some parts from both power supply like - Transistor, IC, Transformer, Resistor etc . Both Power supply has two IC - TL494 and LM339 and Three Transformers

[c_hegge]

OH NO!!!!! I see jumpered input filtering!!!! and undersized components!!!!

Those wouldn't even be legal here.

Are you sure you want to fix those $10 cheapies?? I think it would be more trouble than it's worth, especially since you can get some good units at reasonable prices.

But if you REALLY have no other option, then OK.

When you say it is not switching, what exactly do you mean? Generally, switching implies the primary switching transistors doing their job, so if it's switching, it's running (and if it's not switching, it's not running). What happens if you try to power it on? Does the fan twitch? do you get any 5vsb?

If you do get the fan twitch, then either there is a short circuit somewhere, a protection is being tripped or the contoller IC (TL494) is faulty and is shutting the the unit down un-necessarily. I can't see any obvious solder bridges in the first unit (although the quality does make it a bit hard to tell), but I may have found something in the second unit in picture 2C near the middle. It's hard to tell if it's a solder bridge or just a shadow, but it looks like it could be a solder bridge.

If no fan twitch, then the problem is more than likely in the primary side somewhere, such as a failed switching transistor, transformer or bad start caps (which are really small and don't have vent stamps).

[Galib]

Hahahaha ............ Belive it or not - This is the orginal face of CHINA . They always look to create product within cheap price and shortcut !! They never think about the Quality of Product, they always think for cheap price . LOL CHINA . In my country - there are many products of LOL CHINA, If I give you the pictures of those product, I am 100% sure your Heart will Struck !!! I hate china :shit::shit: .... Waaak thuuuuu !!! But We have no option left without using china . No other country cann't business here because they fail with the competition at Price with the same china Product . China gives the same product Just 1/3 (One-third) price than other countries .

When you say it is not switching, what exactly do you mean?

If you check the good power supply, then you will notice that - The Voltage of three Pins of Switching Transformer will go little higher than normal State when you short the PS-ON with Ground . That means your Controller section is OK and it is working perfectly .

do you get any 5vsb?

Yes, I get 5V PS-ON and 5VSB also .

Does the fan twitch?

No, The Fan does not twitch .

I may have found something in the second unit in picture 2C near the middle

I just check again Output Rectifier with Multimeter - the Rectifier itself and and its connection is OK .

failed switching transistor, transformer or bad start caps (which are really small and don't have vent stamps)

I have checked the Switching transistor, transformer, Fusing Resistor, Crystal and Schottky Diode all of them are OK . When I work in this 13007 Primary section, I always replace these two Start Capacitors 10µF/50V with a new one whether they are good or bad . Which capacitors you are watching in the Picture, they are totally new .

[c_hegge]

hmmm. I'm really beginning to think that it may not be worth investing more time trying to fix a cheap unit that really just belongs in the grabage - even if still working (and I'm running out of ideas ) If I remember correctly, you're from India (unless I'm thinking of another member). I'd highly recommend considering http://www.theitdepot.com/details-Corsa ... P8929.html . Most corsair power supplies are good quality and not overly expensive.

http://www.theitdepot.com/details-Gigab ... P4845.html would also be an option if cou can't afford the extra $10/500INR. I don't particularly like gigabyte "superb" power supplies, but they're still MUCH better than either of those two.

[Galib]

Yes, you are right . I am from India . Hahaha .... Why will I buy Power supply ..... these power supply is not mine . These PSU come to me for repairing . I am a electronics goods repairer .

Just two hours ago - I got another work of repairing of 5 Power supplies . Don't be surprise these are also made by LOL CHINA:shit: Among these 5 PSU, 4 PSU are same as usual . But one power supply seems to be different . Here are the 5 Power supplies .
[attachment=372]

Among them WINSTARS brand looks different . I have attached 2,3,4,5 Pictures for this WINSTARS brand . Still I have not look in deep of this power supply- this is just from top view . I will open it in the last position after working the 4 . I am watching that - In the primay section there is two transistors - one is Large and one is medium . And two Transformer - one is EE-19 Core and another is EE-35 Core . But it has three Optocoupler IC marked in the picture 4 . It has two different looking IC - One is in the Primary high voltage section and another is in Controller section . Currently I am not able to give the IC number because I have not look in the deep yet .

I have not worked such kind of power supply before . Can you help me to figure it out - how this kind of power supply works ........