Author Topic: One hung Lo strikes again.  (Read 4704 times)

0 Members and 1 Guest are viewing this topic.

Offline G7PSK

  • Super Contributor
  • ***
  • Posts: 3698
  • Country: gb
  • It is hot until proved not.
One hung Lo strikes again.
« on: September 27, 2012, 11:52:32 am »
I bought 5 power supplies for Dell laptops and one of them was not recognized by the laptops, I contacted the seller and they sent a replacement, this also did not work so having contacted the seller agin I purchased another unit elsewhere.
As the original supplier does not want the units back and is giving me a refund I cracked the units open.
The first unit that was not recognized a transistor labeled U4 was split open on the second unit the main power capacitor was blown open and as I did not hear a bang on first power up it must have arrived in that fashion.
I am attaching pictures for any one interested.
 

Offline Thor-Arne

  • Supporter
  • ****
  • Posts: 503
  • Country: no
  • tinker - tinker, little noob.....
Re: One hung Lo strikes again.
« Reply #1 on: September 27, 2012, 12:25:56 pm »
I've experienced that those Hung-Lo psu's fails after a while.

Guess it's poor design, Rubycon caps should be good enough (if they're new at least).
 

Online madires

  • Super Contributor
  • ***
  • Posts: 5254
  • Country: de
  • A qualified hobbyist ;)
Re: One hung Lo strikes again.
« Reply #2 on: September 27, 2012, 01:17:40 pm »
I've experienced that those Hung-Lo psu's fails after a while.

They're cheap, they're built to fail. Did you expect anything else? :-)

Quote
Guess it's poor design, Rubycon caps should be good enough (if they're new at least).

... and if they're genuine. Why putting expensive caps into a cheap SMPS if fakes generate more profit?
 

Offline saturation

  • Super Contributor
  • ***
  • Posts: 4788
  • Country: us
  • Doveryai, no proveryai
    • NIST
Re: One hung Lo strikes again.
« Reply #3 on: September 27, 2012, 02:04:54 pm »
Sure spewed a mess of electrolyte.  Well, at least you get some parts to salvage, they can't all be bad.
Best Wishes,

 Saturation
 

Online PA0PBZ

  • Super Contributor
  • ***
  • Posts: 4342
  • Country: nl
Re: One hung Lo strikes again.
« Reply #4 on: September 27, 2012, 02:48:57 pm »
The only way I can think of to blow that Rubycon is a bridge rectifier that's not...
Care to measure that one?
Keyboard error: Press F1 to continue.
 

Offline G7PSK

  • Super Contributor
  • ***
  • Posts: 3698
  • Country: gb
  • It is hot until proved not.
Re: One hung Lo strikes again.
« Reply #5 on: September 27, 2012, 03:07:59 pm »
I was thinking of transferring the U4 transistor from the unit with the blown cap. to the one with the blown U4 transistor and seeing what happens. These units were not the cheapest I could find but not genuine Dell units either I have used them many times before and had no problems it is just that this time it is two failures in succession.The supplier has been helpful but obviously they cost so little to them that they do not want the defective units back or even proof that they do not work.
 

Offline saturation

  • Super Contributor
  • ***
  • Posts: 4788
  • Country: us
  • Doveryai, no proveryai
    • NIST
Re: One hung Lo strikes again.
« Reply #6 on: September 27, 2012, 03:35:35 pm »
... or its a counterfeit, if its a product made in China, always beware of it, its not just the name but the component itself could be functionally completely off.

The only way I can think of to blow that Rubycon is a bridge rectifier that's not...
Care to measure that one?
Best Wishes,

 Saturation
 

Offline G7PSK

  • Super Contributor
  • ***
  • Posts: 3698
  • Country: gb
  • It is hot until proved not.
Re: One hung Lo strikes again.
« Reply #7 on: September 27, 2012, 04:12:30 pm »
Well, I swapped the transistor over and the power unit works, I pulled the rectifier bridge from the other one and checked it there is a dead short in one leg of it.
I am going to use the transformer to make an HT battery re-placer for a 1920's radio that I have, I need about 80 or 90 volts its something that I have bee intending for a long time but have never got around to doing, i will check to find the switching frequency that is used and run it back to front.
 

Online tom66

  • Super Contributor
  • ***
  • Posts: 3767
  • Country: gb
  • Electron Fiddler, FPGA Hacker, Embedded Systems EE
Re: One hung Lo strikes again.
« Reply #8 on: September 28, 2012, 07:27:38 am »
Something about that Rubycon screams FAKE to me...
 

Offline T4P

  • Super Contributor
  • ***
  • Posts: 3706
  • Country: sg
    • T4P
Re: One hung Lo strikes again.
« Reply #9 on: September 28, 2012, 07:42:47 am »
That's not a real Rubycon, it's a poor fake. The negative stripe is all wrong.


Found it in a busted Yihua 858D that no longer works and is beyond repair
 

Online tom66

  • Super Contributor
  • ***
  • Posts: 3767
  • Country: gb
  • Electron Fiddler, FPGA Hacker, Embedded Systems EE
Re: One hung Lo strikes again.
« Reply #10 on: September 28, 2012, 04:42:27 pm »
fake... wrong vent.
 

Offline T4P

  • Super Contributor
  • ***
  • Posts: 3706
  • Country: sg
    • T4P
Re: One hung Lo strikes again.
« Reply #11 on: September 28, 2012, 07:33:27 pm »
Yeah, epic fail
 

Offline FJV

  • Regular Contributor
  • *
  • Posts: 91
Re: One hung Lo strikes again.
« Reply #12 on: September 28, 2012, 08:18:36 pm »
Seems like the unused components would have more value than the finished product.

 

Offline M. András

  • Super Contributor
  • ***
  • Posts: 1020
  • Country: hu
Re: One hung Lo strikes again.
« Reply #13 on: September 29, 2012, 07:56:55 am »
that should be a "k" looking vent
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf