One hung Lo strikes again. - Page 1
Forum section: electronics / general

author: G7PSK
author_rank: Super Contributor
timestamp: September 27, 2012, 11:52:32 am
content: 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.

author: Thor-Arne
author_rank: Unknown
timestamp: September 27, 2012, 12:25:56 pm
content: 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).

author: madires
author_rank: Super Contributor
timestamp: September 27, 2012, 01:17:40 pm
content: Quote from: Thor-Arne on September 27, 2012, 12:25:56 pmThey're cheap, they're built to fail. Did you expect anything else? :-)Quote... and if they're genuine. Why putting expensive caps into a cheap SMPS if fakes generate more profit?

author: saturation
author_rank: Super Contributor
timestamp: September 27, 2012, 02:04:54 pm
content: Sure spewed a mess of electrolyte. Well, at least you get some parts to salvage, they can't all be bad.

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 27, 2012, 02:48:57 pm
content: The only way I can think of to blow that Rubycon is a bridge rectifier that's not...Care to measure that one?

author: G7PSK
author_rank: Super Contributor
timestamp: September 27, 2012, 03:07:59 pm
content: 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.

author: saturation
author_rank: Super Contributor
timestamp: September 27, 2012, 03:35:35 pm
content: ... 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.Quote from: PA0PBZ on September 27, 2012, 02:48:57 pm

author: G7PSK
author_rank: Super Contributor
timestamp: September 27, 2012, 04:12:30 pm
content: 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.

author: tom66
author_rank: Super Contributor
timestamp: September 28, 2012, 07:27:38 am
content: Something about that Rubycon screams FAKE to me...

author: T4P
author_rank: Super Contributor
timestamp: September 28, 2012, 07:42:47 am
content: Quote from: tom66 on September 28, 2012, 07:27:38 amFound it in a busted Yihua 858D that no longer works and is beyond repair

author: tom66
author_rank: Super Contributor
timestamp: September 28, 2012, 04:42:27 pm
content: fake... wrong vent.

author: T4P
author_rank: Super Contributor
timestamp: September 28, 2012, 07:33:27 pm
content: Yeah, epic fail

author: FJV
author_rank: Regular Contributor
timestamp: September 28, 2012, 08:18:36 pm
content: Seems like the unused components would have more value than the finished product.

author: M. András
author_rank: Super Contributor
timestamp: September 29, 2012, 07:56:55 am
content: that should be a "k" looking vent