For anyone interested in power adapter teardowns.. - Page 1
Forum section: electronics / general

author: TimNJ
author_rank: Super Contributor
timestamp: April 26, 2019, 09:39:44 pm
content: Hey all,I work at a power adapter manufacturer, so I'm always interested in checking out the construction techniques and technologies used by other manufacturers. For those of you who are in to power supplies, this Chinese site has great teardowns of lots of popular (and not so popular) adapters. I've enjoyed looking at the Apple adapters. They do some pretty ridiculous things to get everything to fit in the package they want.http://www.chongdiantou.com/wp/archives/category/teardowns/chongdantouFor example, this looks like a custom injection molded part just to hold two capacitors and a common-mode choke in a single-assembly.

author: Electro Detective
author_rank: Super Contributor
timestamp: April 26, 2019, 10:56:45 pm
content: Teardown junkie here, guilty as chargedBesides the usual tools to access mummified adapters (jackhammer, crowbar, sledge, blowtorch, plasma cutter, light sabre etc)I wonder what others use as an alternative?

author: SeanB
author_rank: Super Contributor
timestamp: April 27, 2019, 01:01:56 am
content: I just took apart a potted amplifier module, and for this it took a 3 month soak in MEK solvent to get the epoxy to play nicely with me. That was one tough epoxy block for sure.In general though you find the most common way is the percussive type, hit the joint with a small hammer ( ball peen hitting with the ball side) till the welded part fatigues, or the plastic join where the solvent weld is releases, then use a few spudgers ( preferably, though some big flat blade screwdrivers also are needed) to pop the seam all round, though some the case will need to be cut.To put back together rubber bands to hold while the glue dries works, and I find the best glue to use is a clear contact cement, sold to stick down security alarm cable, which dries fast and is clear, with good adhesion to common plastics and nice gap filling ability. Plus is very cheap as well.

author: TimNJ
author_rank: Super Contributor
timestamp: April 27, 2019, 03:45:46 am
content: Quote from: 3roomlab on April 27, 2019, 12:51:05 amWarning, this website is sometimes slow as hellllll. (Right now, the picture is only like half loaded on my end.)But, YES! I saw that. Totally bonkers. Almost as nuts as having enough market power to request your E-caps without sleeving on the top. I've seen this on a few Apple power adapters. Surely the extra 0.2mm of space savings can't bethatimportant? Thermally related?

author: ElectronicSupersonic
author_rank: Regular Contributor
timestamp: April 27, 2019, 08:17:29 am
content: Quote from: Electro Detective on April 26, 2019, 10:56:45 pmMy favourite weapon of choice is a thick bladed knife (a knife not in Australian sense - a sensible EU type one) with sharp edge placed right in to the seam (starting with corners) and a hammer being used (with reasonable amount of force) to force the blade in. After some persistent hammering, it usually separates cleanly with no plastic broken. It basically "unsticks" the joint so the shell comes apart. If you are careful enough, after glueing the thing back together with epoxy glue, it might look like never been opened (especially if the thing had seen some abuse). An alternative method (haven't tested it myself though) is to use petrol/gasoline/gas. It is to be applied to the seam and after some time the case should separate easily.I use the technique to replace cords (since it's the most common failure). Can't yet repair more then that.

author: German_EE
author_rank: Super Contributor
timestamp: April 27, 2019, 08:43:30 am
content: All agreed about the power cord thing. Right now I have a Thinkpad power supply on my bench and the DC cord is open circuit at the point where it enters the strain relief. They ALL fail at the same point and I've got quite good at pulling the coaxial plus apart so I can resolder the connections.So TimNJ, why do the manufacturers use such crappy DC power cords?

author: Electro Detective
author_rank: Super Contributor
timestamp: April 27, 2019, 09:23:10 am
content: Quote from: German_EE on April 27, 2019, 08:43:30 amThat's Classified info mate, next question please

author: nctnico
author_rank: Super Contributor
timestamp: April 27, 2019, 02:05:47 pm
content: This one is pretty neat (also from Apple). It makes me think of the mechanical casings rxPilot makes...http://www.chongdiantou.com/wp/archives/30093.html

author: Kjelt
author_rank: Super Contributor
timestamp: April 27, 2019, 03:47:28 pm
content: Quote from: TimNJ on April 27, 2019, 03:45:46 amI never seen that besides shrunk due to exhaustive heat.However I know of a German firm upgrading/tweaking av equipment and to conceal the brand of caps they order them without sleeving which seems even for a few reels per value not a problem.These are A brand caps like Rubycon/Nichicon/Mats....PanasonicAlways have problems spelling matsushita ita ta ta

author: TimNJ
author_rank: Super Contributor
timestamp: April 27, 2019, 11:28:51 pm
content: Quote from: German_EE on April 27, 2019, 08:43:30 amHmm I can’t remember the phrase but it rhymes with shplanned shobsolescence.But actually, I’m not too sure. I haven’t heard of too many failures relating to power cords. I also don’t handle RMAs. I would imagine it’s related to the durometer of the jacket and the durometer of the strain relief. (i.e. using a stiff strain relief and soft cable.)

author: wilfred
author_rank: Super Contributor
timestamp: April 28, 2019, 03:47:54 am
content: Quote from: Electro Detective on April 26, 2019, 10:56:45 pmI start with a trick @Mikeselectricstuff (IIRC) showed where you give the seam a few hard taps with a large screwdriver handle. I've found it works often enough to be tried always. If that doesn't work then I use rubber bands to hold a pair of pencils alongside the seam and squeeze it in a vice. The pencils direct the pressure to the seam. Next I bash it with a hammer because I am frustrated by now and I am losing focus on reassembling it cleanly.Then a rotary cutting tool.Maybe if I remember I'll check the label to see if there is a screw under it.

author: TimNJ
author_rank: Super Contributor
timestamp: April 28, 2019, 03:16:47 pm
content: Two methods that work pretty well.1.) Using heavy duty side cutters, clip each of the four corners of the plastic housing. Many times, this is enough to break the entire seal. If not, bring it over to an arbor press (or bench vice), rotate unit at a 45 degree angle (so that the edge of the press is pressing on the seal) and push!2.) Set up a small table saw so that the blade only protudes a few millimeters. Position the fence so the blade runs right along the sealing seam. This one takes more effort to set up but good if you need to open many of the same units.

author: Electro Detective
author_rank: Super Contributor
timestamp: April 28, 2019, 10:37:47 pm
content: Quote from: TimNJ on April 28, 2019, 03:16:47 pmIn fairness, if doing a few identicalsealed to survive a point blank phasor blasttough dog LRD units (Landfill Repair Design)I give them the option to draw straws who goes firstThe first one is always the hardest, once cracked open it's obvious what the manufacturer was thinking (or not)and work out an easy/better pleasing aesthetic 'never opened' close up solution..once the device has been repaired/upgraded/resoldered/re-grommetted/all the guts swapped out/etc..You always know it's a cloudy day outside when you have a few of these suckers on the bench, and all different or one off weird style PITAs,and cracking them open may be the easy part

author: Red Squirrel
author_rank: Super Contributor
timestamp: April 29, 2019, 01:27:29 am
content: I did a teardown of one a while back if anyone interested. Nothing too special and I don't really go into the technical details or anything but thought I'd share since we're on the subject.

author: TimNJ
author_rank: Super Contributor
timestamp: April 29, 2019, 06:10:29 pm
content: Quote from: Red Squirrel on April 29, 2019, 01:27:29 amOh man, that's about as chintzy as they get. As you point out, the primary-secondary clearance is completely unacceptable. It should never really be below 4mm. 8mm is a good rule of thumb to comply with most safety standards, medical or ITE (information technology equipment).