How to open Samsung Power Supply?

Thread Starter

zophas

Joined Jul 16, 2021
165
Any ideas how to open this Samsung Monitor Power Supply? There are no visible screws and I don't feel any indents under the label. I'm at a loss as to how to open it to hopefully effect a repair. SamsungPower1.jpg
 

Ya’akov

Joined Jan 27, 2019
6,561
It's not going to be easy. The construction of that sort of supply is based on a tight-fitting, glued seam. One side will have an overlapping lip.

There are a few ways you can try.

First is the protoype of brute force: a hammer. Preferably a stout, plastic headed mallet. I haven't had much luck with the ubiquitous plastic dead blow type though. The down side of this is if you don't break the glue joint in the first couple of strokes you are going to be subjecting the suppy to a lot of percussive punishment.

Hit the supply on the long narrow edge. At some point you will hear a crack or pop. Stop and try using a screwdriver to pry the halves apart. You may have to repeat to increase the freed section.

Second is with a bench vise. Pad the jaws with a couple of layers of cardboard or something similar and place the supply facing up and halfway in, to just below the seam. Make sure at least one end is in the jaws . Unless you have a massive vise you'll have to choose one. I have had more success, anecdotally squeezing the output end.

Slowly tighten the vice. At some point you will hear a crack or pop. Stop and try using a screwdriver to pry the halves apart. You may have to repeat on the end you didn't originally do.

Last, try a dremel with an abrasive cutoff wheel. Cut no more than until it penetrates the case, you can do a lot of damage if you cut too deep. First try cutting in a corner, then using a screwdriver in the slot and pry by twisting the screwdriver. You may get it all open quickly, or you may have to cut other corners or along the side. You want as much uncut as you can persevere for reassembly using the overlapping parts.
 

MrChips

Joined Oct 2, 2009
27,117
First question: Why do you want to open it?
It is a transformerless switched-mode power supply. These are very difficult to repair and are lethal if you don't know what you are doing.
 

MaxHeadRoom

Joined Jul 18, 2013
25,979
Some time ago I purchased a tool kit for dismantling latest electronics, IPAD's etc, that are constructed in this 'screw-less' manner.
Consists of several flat bladed tools that do not bend when removing the case.

1657549342510.png
 

Thread Starter

zophas

Joined Jul 16, 2021
165
First question: Why do you want to open it?
It is a transformerless switched-mode power supply. These are very difficult to repair and are lethal if you don't know what you are doing.
It popped due to very frequent power cuts in my country. Luckily I had a spare one which I could use after changing the plug. I am aware of the shock hazards but I am hoping I can fix this in case the other one fails. We are still getting the power cuts.
 

Ya’akov

Joined Jan 27, 2019
6,561
Some time ago I purchased a tool kit for dismantling latest electronics, IPAD's etc, that are constructed in this 'screw-less' manner.
Consists of several flat bladed tools that do not bend when removing the case.

View attachment 271229
These sort of tools will work very well once you have the glue crack somewhere. You can get it in the crack and slide it along. Always away from your body and the hand not using the tool. If the tool slips it can lead to disassembly of your self.
 

ThePanMan

Joined Mar 13, 2020
494
I've opened those types of PS's using just an exact-o knife blade and handle. Using the pointed end but using the back edge (flat - not sharp) to score along the seam repeatedly until I've penetrated the plastic body. Do that on all four sides and you'll likely be left with just the four corners to cut through. Using the same methodology continue at the corners until you've managed to open the case. if the plastic remaining is very thin you can usually break that open.

But once they're opened, there's a whole lot of stuff that isn't easy to replace or repair. There are some larger components like caps and diodes that might be replaceable, but chances of fixing it are dubious at best. The ones I've opened - I've opened to modify. One currently in use was (WAS) a 12V output. I modified it to a 13.6V output to keep an old car battery at float voltage to power a car radio. It's useful, but its only purpose is for that radio and voltage. And with differing designs - you really need to know what part of the circuit to modify.

Still, if you want to open yours - I'd opt for an exact-o blade and use the back edge of the blade to score along the seams until I've scored my way through. But then you have the issue of closing it back up when done. You CAN glue it closed, but I've had issues finding a good way of gluing plastics in the past. Some plastics just don't like glue. Super-glue might work; might not. I've had very limited success with SG. Perhaps - and I haven't tried this before - PVC cement might work better. But I don't know. The way I closed mine was with hot melt glue then black electrical tape to encapsulate the unit.
 

Dodgydave

Joined Jun 22, 2012
10,497
You need a flat blade screwdriver or something similar or a Dremel, and work your way around the seam , these are ultrasonic welded .
If it's blown there is a fuse on the mains input side, but it could have blown because the Mosfet has gone too.
 
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Externet

Joined Nov 29, 2005
1,929
After the effort of opening the case;
without harming yourself,
if you know what you are looking at inside,
with no schematic,
with no skills to troubleshoot it,
no spare parts available at your location
if any is identifiable after exploded,
It will be another item in your junk box.
So better dedicate your efforts to find one that replaces it by label specifications and connector type. Which seems a laptop supply made by the millions and if there is a recycling center or a electronics repair shop around, chances to find one are good. Just cross fingers that the supply is the damaged and not the laptop. :rolleyes:

As an extraordinary event, once I managed to have the power transformer replacement of my very expensive stereo receiver ordered and paid by the electric company after their goofing damaged it. Found they do have a budget to cover customer repairs from their mistakes.:oops:
 
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Reloadron

Joined Jan 15, 2015
6,963
While not designed to be opened or serviced my weapon of choice is a Dremel tool with a cutter wheel mounted on it. On the off chance you get it apart for reassembly a run a bead of super glue around the cut and clamshell it back together using a few rubber bands to hold it till the glue dries. Lacking a Dremel tool I have used an old hacksaw blade or just scored the seams over and over again with a knife. Just make sure you are careful. :)

Ron
 

Thread Starter

zophas

Joined Jul 16, 2021
165
As an extraordinary event, once I managed to have the power transformer replacement of my very expensive stereo receiver ordered and paid by the electric company after their goofing damaged it. Found they do have a budget to cover customer repairs from their mistakes.:oops:
The power cuts in my case are nationwide and effect everyone else too. I have heard of many other people suffering equipment failure of many sorts. No one has ever been compensated by the only power company we have.

Edit: We even made it to Wikipedia. https://en.wikipedia.org/wiki/South_African_energy_crisis
 
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DickCappels

Joined Aug 21, 2008
9,317
I repaired a printer power supply in a similar enclosure. I opened it up with a hacksaw while the power supply was held in a vice. It takes a gentle touch an a lot of removing the blade to observe progress in order to just barely cut through the plastic.

Just remember not to touch any circuitry while the thing is plugged into the AC power source.

After the repair is seen to be successful you should glue the pieces (in this the plastic enclosure and the lower case "lid" back together for one thing, to keep flames from propagating in case of a failure that would make that happen. Epoxy would probably be better if it cannot sustain a flame.
 

MrChips

Joined Oct 2, 2009
27,117
Many of my electronics are plugged into power bars.
When there is a power outage I run around the house and turn off all the power bars and unplug electronics.
 

Thread Starter

zophas

Joined Jul 16, 2021
165
Many of my electronics are plugged into power bars.
When there is a power outage I run around the house and turn off all the power bars and unplug electronics.
I do the same with some of my appliances (fridges, Water heater). My computer equipment is on a UPS which I'm told helps with the constant on-off. But I still have to switch it off after shutting down my computer as it only lasts about 10 minutes. In good times my computers run 24/7.
 

Thread Starter

zophas

Joined Jul 16, 2021
165
Ok I got the supply open using tips from here. Thanks to all. No obvious damaged components. No Magic Smoke evidence. Whatever failed did so peacefully. I do see a small round orange 2A fuse next to the input power plug but I don't think it would be as simple as that. I'm calling this one beyond my capabilities. @bassbindevil Thanks for the thrift store tip.
SamsungPSU.jpg
 

ThePanMan

Joined Mar 13, 2020
494
Somebody here mentioned going to places like internet provider stores where you can get modems for their systems. Many modems have external 12V power supplies, often 2 or 3 amps. I've since found that going to satellite stores you can also find PS's there as well. I got (for free) one rated for 5 amps. But thrift stores are also a potential source.
 

Dodgydave

Joined Jun 22, 2012
10,497
Ok I got the supply open using tips from here. Thanks to all. No obvious damaged components. No Magic Smoke evidence. Whatever failed did so peacefully. I do see a small round orange 2A fuse next to the input power plug but I don't think it would be as simple as that. I'm calling this one beyond my capabilities. @bassbindevil Thanks for the thrift store tip.
View attachment 271305


As you mentioned the fuse, you could check the Mosfet and bridge rectifier, otherwise just bin itIMG_20220712_193328.jpg
 

Thread Starter

zophas

Joined Jul 16, 2021
165
Thanks @Dodgydave . I am reading thru a thread in the power section where someone is trying to fix/learn about a printer SMPS.
When I am done with that I will decide what to do about my supply. Thanks.
 
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