Cheap power supply tear down - Page 1
Forum section: electronics / testgear

author: wd5gnr
author_rank: Regular Contributor
timestamp: October 15, 2015, 06:21:07 pm
content: http://hackaday.com/2015/10/15/looking-inside-the-arksen-dual-power-supplyDoesn't seem too bad if you trash the leads and also never ever ever turn it on and off with something connected to it. On the other hand, that's kind of a gamble. Even with a small load on it, it threw pretty big spikes.

author: AF6LJ
author_rank: Unknown
timestamp: October 15, 2015, 06:49:14 pm
content: This sums up why one fo the first projects a tech or hobbyist should take on is a homebrew power supply, unless you buy something used and re-cap it.If I were those two transformers on that chassis, I would ask to be liberated from that pile of crap.

author: wd5gnr
author_rank: Regular Contributor
timestamp: October 15, 2015, 07:43:36 pm
content: If you were both of them you'd suffer from split core personality disorder ;-)

author: AF6LJ
author_rank: Unknown
timestamp: October 15, 2015, 10:31:40 pm
content: Quote from: wd5gnr on October 15, 2015, 07:43:36 pmOr it would be my twin and I....

author: wd5gnr
author_rank: Regular Contributor
timestamp: October 15, 2015, 10:40:53 pm
content: Which of you did mother like best? ;-)

author: crispy_tofu
author_rank: Super Contributor
timestamp: October 16, 2015, 12:28:02 am
content: Eek, personal preference but I hateTimes New Romanon test equipment. It feels like it doesn't belongMust be hot and sticky in there.

author: AF6LJ
author_rank: Unknown
timestamp: October 16, 2015, 12:32:18 am
content: Quote from: wd5gnr on October 15, 2015, 10:40:53 pmIt wasn't me, long story.

author: nowlan
author_rank: Frequent Contributor
timestamp: October 16, 2015, 08:58:07 am
content: I thought these things were all clones. Seems expensive to me.Not sure why all the components are at different angles, and cables everywhere.Is there no standard for manufacturers to address these switch on/off issues etc?

author: Kleinstein
author_rank: Super Contributor
timestamp: October 16, 2015, 09:21:29 am
content: Many of the cheap supplies are just clones / rebranded versions of a few designs. However this one looks a little different:quite a lot of cables hangig around and a could not see a fan near the heat sink, which is way to small to work without it.So I would consider this one a rather poor version - expensive to build and possibly even dangerrous if mains and and output side cables are mixed together.

author: rdl
author_rank: Super Contributor
timestamp: October 16, 2015, 01:36:28 pm
content: I was surprised he seemed okay with the whacko voltage output at start up.QuoteThat is not acceptable.

author: wd5gnr
author_rank: Regular Contributor
timestamp: October 16, 2015, 04:40:58 pm
content: There are two fans on the rear. Somehow they never got into a picture.

author: SharpEars
author_rank: Unknown
timestamp: October 16, 2015, 04:44:28 pm
content: Quote from: wd5gnr on October 15, 2015, 06:21:07 pmOne circuit breaker pop (also caused by this supply) or power failure and you can kiss you circuit under test goodbye with these puppies.

author: SharpEars
author_rank: Unknown
timestamp: October 16, 2015, 04:45:48 pm
content: Quote from: wd5gnr on October 16, 2015, 04:40:58 pmTwo fans, because the fan failure percentage is 50%. When you buy the supply, chances aren't too bad that one of the fans will be operational.

author: SharpEars
author_rank: Unknown
timestamp: October 16, 2015, 04:47:33 pm
content: There is exactly one cheap Chinese supply that is not made (i.e., cloned) by Mr. "Some Ting Wong" and that is:Gopher CPS-3010If you get anything else, you are asking for serious trouble.

author: dom0
author_rank: Super Contributor
timestamp: October 16, 2015, 04:59:34 pm
content: Quote from: rdl on October 16, 2015, 01:36:28 pmYeah, I say that over and over again. The designer of a lab supply that doesn't even power up cleanly clearly doesn't give a shit about the design, so what can one expect from such a supply?About freeing transformers ...... they are probably low-grade. Poor core material, bad potting, lots of humming, maybe even isolation that wouldn't hold up in a serious test. High quality transformers can be acquired so cheaply today, I simply wouldn't bother with those. Also, for a good lab supply for analog stuff you really want a transformer with electrostatic shielding. They are a bit harder to come by, and more expensive.

author: AF6LJ
author_rank: Unknown
timestamp: October 16, 2015, 08:04:08 pm
content: Quote from: dom0 on October 16, 2015, 04:59:34 pmAgreed.