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Old 08-24-2016, 10:12 AM   #1
DesperateDude
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Angry Axle typhoon ax-p400l (400W) PSU Dead

Hi people

I came here looking for helps I saw how you guys helped for PSU repairs. Let me tell you my story

I have an Axle typhoon ax-p400l PSU which is 400W but suddenly it stopped working because of a lightning strike which came from Network port.

You may have not heard of this PSU, it's a Chinese made PSU not a high end one like expensive ones over there, but it did me a decent job.

Computer was intact but is PSU dead.

I checked it with my digital multimeter and I saw all the cables have power but it was very low. Like around 2V from 12V cable and etc.. Everything I measured had similar problem. All the pins were around 2V or lower.

So I disassembled the PSU and saw only a 10 ohms resistor was burned but still worked with a burning smell. This resistor is connected to the VCC pin of SG6105DZ. So it seemed like a failure with the IC but I tested some more and saw getting 6V for that said VCC pin.

Now comes the unfortunate part

When I was testing these I accidentally shorted 2 main capacitors of the primary.

Then I tested and shocked to see no power to the secondary side.

There is a DM311 in the primary side and I tested that too. It was not getting any voltage for its VCC pin.

Then I tested all the components near that IC. Found an opened 1ohm resistor and I replaced it. But no avail.

So I checked everything in primary side with my digital multi-meter. And found nothing..

Then I decided to replace all ICs of the board. There is another IC labeled as WT7518D near that SG one.

Then I checked and no changes. Then I went desperate and checked all the components which I couldn't check before.

Only things I didn't check were non fusible resistors and small electrolytic capacitors.

I found only 2 components burned. One was C12 5T Zenner diode (went open) near SG6105 and the optocoupler labeled as 817CN (LED side was burned)

I even checked the 3 transformers.

Even after doing all these no changes (Replaced Optocoupler and replaced Zenner diode with a 12V one). No power to transformers and nothing for secondary side.

I had enough and thought to ask from you geeks

PS: I don't have an ESR meter or Capacitance tester. All did using the digital multimeter.

I am attaching pictures of circuit below..

Sorry for the long story and there may be some grammatical errors in my English because I wanted to type fast and let you guys know



Thank you


Frontside 1
Frontside 2
Backside

Last edited by DesperateDude; 08-24-2016 at 10:15 AM..
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Old 08-25-2016, 01:05 AM   #2
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

Also I forgot to mention this before,

3.3V output is shorted to the Ground too.
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Old 08-25-2016, 02:53 AM   #3
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

check the 3.3v diode - dont be tricked by any low value load resistors
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Old 08-25-2016, 04:45 AM   #4
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Smile Re: Axle typhoon ax-p400l (400W) PSU Dead

Hi

Thank you for replying

As I said earlier I checked all the diodes and fusible resistors (Not just fusible ones I checked some other ones too but not all) but didn't find any problematic ones. I am clueless
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Old 08-25-2016, 10:37 AM   #5
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

Quote:
Originally Posted by DesperateDude View Post
Also I forgot to mention this before,

3.3V output is shorted to the Ground too.
When you said shorted to GND, what resistance are you seeing? <1 Ohms? There has to be shorted component in that 3.3V Output section. What do you get when you remove the rectifier or Zener protection diode in that section, the shorts go away? Something is being overlooked.
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Old 08-25-2016, 11:58 AM   #6
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Smile Re: Axle typhoon ax-p400l (400W) PSU Dead

Thanks for the reply budm.

I checked using continuity test mode and I get a beep and a resistance of 17 ohms.

Also for 12v line I get a sudden beep and then resistance increases. I think that's normal and that's because of the related capacitors.

I checked all the diodes there also even transistors (little ones which were even near the Fan connector) but found nothing..

But I couldn't check for shorts after removing the diodes when I was testing the PSU.

Also by the way I see something very strange that is, There is a transistor of the secondary side. Which is a big one and also connected to the heatsink with the 2 schottky diodes.

And all 3 pins of that one are shorted with each other. This is only when the transistor is soldered to the board. And after removing, transistor was tested good. Only happens when installed back.

Last edited by DesperateDude; 08-25-2016 at 12:01 PM..
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Old 08-25-2016, 12:16 PM   #7
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

17 Ohms is not shorts. Continuity mode in the meter is only good for checking the continuity from point A to point B, not for checking for shorts circuit.
Some meter will beep with up to 100 Ohms resistance, it beeps does not mean it showing shorted circuit.
That resistance reading may be the bleeder resistor.
You have to do more tracing on the board.
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Old 08-25-2016, 12:47 PM   #8
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

Thank you for the correction.

Yes the meter do sounds even for 12 ohms.

For your information, as I said earlier I did check almost everything and confused then I had no choice but to ask from you guys
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Old 08-27-2016, 12:54 PM   #9
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

Anyone?
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Old 08-28-2016, 09:54 AM   #10
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

resistance of vcc of DM311
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Old 08-28-2016, 11:39 AM   #11
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Smile Re: Axle typhoon ax-p400l (400W) PSU Dead

Quote:
Originally Posted by joshnz View Post
resistance of vcc of DM311
Thank you for the reply,

As I remember it has no voltage and also no meter readings for ohms.

To check better, to what pin I must connect negative probe of the meter? Ground pin of DM311 or common ground ?




Thank you..
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Old 08-30-2016, 02:03 AM   #12
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Question Re: Axle typhoon ax-p400l (400W) PSU Dead

Quote:
Originally Posted by joshnz View Post
resistance of vcc of DM311
Hi

I just measured the resistance and I got 20.7K
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Old 08-30-2016, 02:08 AM   #13
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

Do you have standby power?
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Old 08-30-2016, 03:13 AM   #14
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Unhappy Re: Axle typhoon ax-p400l (400W) PSU Dead

Quote:
Originally Posted by joshnz View Post
Do you have standby power?
No no power. Nothing at all..

Even secondary side of the PSU circuit has no power. SG6105DZ not even getting VCC power.

Basically no power is supplying to the secondary side from the primary. All the transformers have no power at either side. DM311 only getting 7V for its 8th pin and around 300V for its 5,6 and 7 pins.
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Old 08-31-2016, 01:40 AM   #15
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

Any one?
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Old 08-31-2016, 05:29 AM   #16
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

get a DM311 datasheet and look at the example schematic
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Old 08-31-2016, 06:20 AM   #17
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Unhappy Re: Axle typhoon ax-p400l (400W) PSU Dead

Quote:
Originally Posted by stj View Post
get a DM311 datasheet and look at the example schematic
Thanks

But that's the first thing I did when started to repair this
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Old 02-09-2019, 08:53 AM   #18
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

Hi Guys,

After around 2.5 years I've decided to repair this again.

So here is what I did,

I had 2 more DM311 ICs around, I don't know if they are good or bad. So I tried them all.

Same issue and PSU doesn't turn on. But I saw something new.

For one IC I got around 1.3V for the 5th pin which is the Vstr pin.

And I tried the other 2 ICs too. Then for those 2 I got around 6.6V for the Vstr pin and that's all I got.

No power to the secondary side (Not even 5v standby) or no power to the Vcc pin (pin 2). I've checked all the diodes ,capacitors and resistors around the IC but non of them were bad.

I also noticed getting around 0.37v for the Optocompler's anode and cathode.

But that's all I saw. I am going to order some more DM311 from eBay to try swapping the current ones.

In the meantime could you guys help me out with this if you have any ideas? Are the transformers bad or anything else? I've checked the transformers with the multimeter.
I really appreciate any help you are willing to give me..

In case of if you can't view my old uploaded images of the circuit board. Here are new links

https://www.dropbox.com/s/lbch7ytz4n..._0007.jpg?dl=0
https://www.dropbox.com/s/ez9yrgypa0..._0008.jpg?dl=0
https://www.dropbox.com/s/a5b0ngljcy..._0009.jpg?dl=0





Thank you.
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Old 02-11-2019, 12:57 AM   #19
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Default

Anyone?
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Old 02-11-2019, 02:18 AM   #20
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Default Re: Axle typhoon ax-p400l (400W) PSU Dead

Quote:
Originally Posted by DesperateDude View Post
Hi Guys,

After around 2.5 years I've decided to repair this again.

So here is what I did,

I had 2 more DM311 ICs around, I don't know if they are good or bad. So I tried them all.

Same issue and PSU doesn't turn on. But I saw something new.

For one IC I got around 1.3V for the 5th pin which is the Vstr pin.

And I tried the other 2 ICs too. Then for those 2 I got around 6.6V for the Vstr pin and that's all I got.

No power to the secondary side (Not even 5v standby) or no power to the Vcc pin (pin 2). I've checked all the diodes ,capacitors and resistors around the IC but non of them were bad.

I also noticed getting around 0.37v for the Optocompler's anode and cathode.

But that's all I saw. I am going to order some more DM311 from eBay to try swapping the current ones.

In the meantime could you guys help me out with this if you have any ideas? Are the transformers bad or anything else? I've checked the transformers with the multimeter.
I really appreciate any help you are willing to give me..

In case of if you can't view my old uploaded images of the circuit board. Here are new links

https://www.dropbox.com/s/lbch7ytz4n..._0007.jpg?dl=0
https://www.dropbox.com/s/ez9yrgypa0..._0008.jpg?dl=0
https://www.dropbox.com/s/a5b0ngljcy..._0009.jpg?dl=0





Thank you.
Please post photos using the attachment button. Off site hosting of photos is a real pain in the butt.
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