Trying to fix a 12V 5A PSU | No output power supply repair

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Sometime it amazes me how I manage to fix anything. After watching this, I wouldn't trust myself to re-wire a 13A plug.
Got there in the end and I'm putting it out there to show others, that we all have days where our brains, take a day off and we end up taking the long way around.
I have set up a Patreon account where I'll be posting photos and videos of upcoming projects and what I'm currently working on.
/ philipbryden
Enjoy the video.
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Website: www.philbryden.co.uk/
Twitter: / philbryden
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Tools:
Multimeter: AstroAI Digital Multimeter, TRMS 6000
Soldering Iron: KSGER T12 Soldering Station
Hot air station: Quick 857DW+
Bench PSU: Tenma 72-2540 30V 5A
Digital Oscilloscope: Rigol DS1054Z
Desolder pump: Duratool
Miscroscope: • Micro soldering set up...
Disclaimer:
The information provide in this video is for entertainment use only.
I am not a professional and any methods I use might not be the correct ones.
I will not accept any responsibility for loss, damage or injury as a result of the information provided in this video.

Развлечения

Опубликовано:

8 июн 2024

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Комментарии : 59

@mart43 Месяц назад

The green component is an inrush resistor NTC. An MOV (Metal Oxide Varistor) is a device that short-circuits when exposed to high voltage 10KV. It is placed between the live and neutral wires, which is why a direct short occurred. As electronic devices age, it is quite common for MOV to fail.

@PhilipBryden Месяц назад

Honestly I could have saved myself a whole load of work if I had just slowed down, examined the components, read the screenprint on the board and not jumped to conclusions. I do this stupid stuff all the time. Thanks for the info on the MOV.

@wisher21uk Месяц назад

Hit the case with a hammer and the letter T before the amperage i.e. T5A /240v the T stands for time delay (slow blow) Brilliant fix well done mate 😊

@PhilipBryden Месяц назад

Thanks Gary. I got the correct fuses, the extra ones will no douby come in handy at some point.

@wisher21uk Месяц назад

@@PhilipBryden well done that man best to be safe then sorry 😊

@g4z-kb7ct Месяц назад

You can test a ntc/mov by heating it up and the resistance should change. If you are unsure whether the bridge is good or not (it seemed that way) to test a bridge remove the next component in line so the DC output doesn't go anywhere then you can measure the AC and DC voltage on the bridge.

@pietpaaltjes7419 Месяц назад

I am glad to see you used the dim bulb tester. That saved your day :-) I was a bit worried when you replaced the mov with something you did not know.

@PhilipBryden Месяц назад

That simple bulb set up has saved a few things and it's so easy to make. Definitely worth the effort. Thanks for watching.

@davidgranger3628 Месяц назад

I use a soldering iron with a knife blade in it to cut a slot .Another good way would be a ultrasonic knife but they are expensive

@PhilipBryden Месяц назад

Strange but I just using my old soldering iron yesterday to melt away plastic resin from a waterproof LED light. I've not heard of ultrasonic knives, I will have to see what they are.

@davidgranger3628 Месяц назад

@@PhilipBryden i bought a hot branding iron ,its just a soldering iron you can insert tips in to make patterns in wood and in amongst it was a small scalpel type knife .Its great for cutting holes and slots in plastic but ofcourse its melting the plastic so you dont keep it in one place or it just melts the slit wider. The ultrasonic knives use high frequency to melt through but as it only touches a tiny bit the slit it produces is far cleaner . The hot version Weller WHK30UK

@tommy3410 Месяц назад

I use gasoline, outside in the open air, to open the case, it penetrates and softens the solder perfectly. Pour the drop to trickle down the thermal or ultrasonic bonding line all around, usually and in most cases it works easily and cleanly. Greetings from Romania.

@PhilipBryden Месяц назад

Hello Tommy. I don't normally have gasoline or petrol on hand but I wonder of lighter fluid would work too. Thanks for the suggestion 😉

@tommy3410 Месяц назад

@@PhilipBryden Hello, You know better. Acetone dissolves something easier, gasoline something else easier and so on, I don't know the thinner or lighter gas... I noticed that Sorin doesn't lack gas either, a romanian guy from you from the UK who has the "Electronics repair school" channel, I warmly recommend him.Good luck.

@anthonydenn4345 Месяц назад

A channel lock pliers is good for these. Just pinch it all around at the seam.

@vhfgamer Месяц назад

Well that's freaky. I was just working on a power supply that looks identical to the one you have, except mine is rated at 3.5 amps 12 volts. I'm using it to power a home built guitar amp. I paused to eat some lunch, and here you are working on the same supply. Tech tip. When you have supplies like this which are a pain to get open, try squeezing it in a vice. Often times that flexes the whole case and cracks the sonic weld.

@PhilipBryden Месяц назад

Ha ha I did try gripping it with an Irwin quick clamp but it didn't have any impact. This thing was really glued together tight. Good luck with that amp.

@mrdovie47 Месяц назад

If you ever work on a stepper motor that jams or won't run. I fixed many of them by looking for chipped ferrite magnets the chip will jam the motor remove and good as new. The motor was dropped or hammered to make the chip.

@PhilipBryden Месяц назад

I will try to remember to examine the ferrite magnets. I jump to conclusions too quickly at times, my approach needs to be more analytical and patient.

@g4z-kb7ct Месяц назад

The easy way to open those boxes is to use a large flat-bladed screwdriver, place it on the join and give it a sharp tap with a hammer. I mean a sharp tap, like putting backspin on a cue ball, not a hurculean death-blow lol. Do that all the way around and that will crack the heat-fusing and it should come apart easier.

@PhilipBryden Месяц назад

Next time I'll try using a hammer and a wide blunt chisel to break the seal like you suggest. Thanks.

@mikecass8306 Месяц назад

Well done Phil, you got there in the end, stay safe 😁

@PhilipBryden Месяц назад

Cheers Mike. I have a couple of NES's and replacement 72 pin connectors on the bench for the next video. Hopefully there's no surprises when I open them up.

@RWCSNZ Месяц назад

Hi, some of those cases don't glue that well so after gluing the case shut i use a couple of plastic ties

@PhilipBryden Месяц назад

Good call. It's a spare at the moment but If I were to use it then some ties or electrical tape to secure the case would be a good idea. 👍

@wakkowarner7391 Месяц назад

I spend many hours at work fixing switched mode power supplies. They can be a real pain.

@PhilipBryden Месяц назад

I see a lot of people advising against working on PSUs, but I quite like the challenge.

@wakkowarner7391 Месяц назад

Common sense goes a long way :)

@nyeleskettes Месяц назад

Did I see right he straight up removed the PCB from the housing without discharging the buffer capacitor? That my friend holds enough charge even after a week to send you across the room - dont ask me how i know it.

@PhilipBryden Месяц назад

Ouch. I was being careful not to touch the PCB. So far I haven't had a proper whack from anything I've been working on, just some sharp tingles lol. The last one was when I picked up the probes of an LED tester by the wrong ends while it was switched on.

@dingleberry2848 Месяц назад

perfect example how you learn by doing it ;) its probably not worth it moneywise, cause you cant charge decent money for such a repair but education and gaining XP is the point i believe. Good job! Cheers (Im not a pro but I can fix anything this way)

@PhilipBryden Месяц назад

Yeah mistakes like this are painful but sometimes provide a really good learning experience. Thanks for leaving a nice comment.

@edwardreichard3852 Месяц назад

Well done Phil!

@PhilipBryden Месяц назад

Thanks Edward. For some odd reason RU-vid has been promoting this one. Managed to pick up a few new subscribers too.

@frozerinosrepairs Месяц назад

Great video ❤❤❤

@PhilipBryden Месяц назад

Thank you Froz. I hope you're well.👍

@frozerinosrepairs Месяц назад

@@PhilipBryden everything good 😊😊

@Moonball1981 Месяц назад

Jesus Phil your some Butcher… 😀 But that’s why we love ya. I learn more from your videos than anyone else’s. Thanks again for the videos.

@PhilipBryden Месяц назад

How dare you! lol. It's not my fault the case wouldn't open 😒 Thanks for the message of encouragement. Glad someone likes the videos!

@dubstatic Месяц назад

I find the easiest way to open these is a lump hammer and a wide chisel, hit hard and shock it open

@PhilipBryden Месяц назад

Thanks for the tip, I'll look out for a wide chisel to use in future.

@matthewmaidment8464 Месяц назад

Philip how the devil are we, hope all good 👍🏼

@PhilipBryden Месяц назад

Yeah I'm great. Just been doing other stuff. How are you Matthew?

@broderperdurabo Месяц назад

Put them i a freezer. Easier to crack open.

@PhilipBryden Месяц назад

I'll try that for the next one. Perhaps pop it into a plastic bag first to try and avoid any frost or condensation building up.

@MrBobWareham Месяц назад

They are plastic welded together, so all you can do is dremel with a cutter on the seam and glue back again

@PhilipBryden Месяц назад

I have a Dremel but I was worried about going through the case and into any components.

@VVerVVurm Месяц назад

@@PhilipBryden I would vote against using a Dremel to open this kind of case. It was what I first used and it makes a royal mess. I then used my hot air station and a knife along the seams which took a long time but was better. Last time I opened up my laptop power supply to fix it I used lighter fluid on the seam (used a glass syringe) and it came apart clean - still took some time. It all depends.. some cases open up easily and others are stubborn..

@PhilipBryden Месяц назад

Ah that might have worked. I have some IPA in a little bottle for precise applications. Maybe some of that in the seam could have loosened it up. This one was definitely one of the tougher ones to open.

@VVerVVurm Месяц назад

@@PhilipBryden yes it worked for me - but I think it must have been glued shut. If it is was welded I would have progressed to acetone which desolves ABS plasitc - but the black plastic sludge sticks to everything and again makes things messy

@ianhaylock7409 Месяц назад

"Two a penny". Well there's inflation for you, it used to be ten a penny. Sometimes you can squeeze the PSU case in a vice to break the case apart.

@PhilipBryden Месяц назад

I remember when you could buy a 10p mix up too lol. The good old days. I did try to grip it in a clamp but didn't have much luck.

@aurthorthing7403 Месяц назад

So... you need a lot more practice taking those sealed cases apart. I suggest a large pair of water pump pliers...and a small ball peen hammer.

@PhilipBryden Месяц назад

I need more practice reading what's written on the components too lol. I'll try clamping and tapping the next one, to see if it's any easier. Thanks.

@bobwarren2590 Месяц назад

this is why they make dremel tools

@PhilipBryden Месяц назад

I have a dremel but I was concerned about cutting through a component and being able to glue it back together after I had cut through the seam.

@preston963 Месяц назад

7:32 It's not a Thermistor it's a 470V Varistor that's across the mains to clamp spikes, protect p/s & blow fuse... 19:12 The little one is a in rush Thermistor... OMG That was painful for a 10 minute fix, been a tech 40yrs, BTW You didn't have to destroy the case IPA will dissolve the glue with patients.

@PhilipBryden Месяц назад

I know, I know. I'm sorry lol. Even after I checked the writing on the components and searched online, I still didn't notice one was a varistor and the other a thermistor. I'm so ashamed lol. It took me six weeks to get around to fitting the new fuse and the correct part. Editing was painful but I left the whole lot in. I'm glad I uploaded the video, it's been one of my most successfull videos to date and it's an absolute shambles of a repair attempt. Thanks for the supportive comments.