I have watched many of the previous videos and I notice that you have always put out a warning regarding the high voltage capacitor warning. Appreciate the warning to all noob electricians. Kudos.
I've repaired a number of video monitors with blown 5v internal supplies simply by bypassing them and fitting eBay buck converters instead ... Works a treat! A couple of quid and a few wires ... Job done. Cheaper, quicker & easier than buying individual components and repairing directly on the board. 👍👍👍
@@blackterminalsorry! Too much other stuff on. Plus, with the number and variety of different monitors around even from just one supplier, it wouldn' t help anyone unless they had the exact model. You need to be experienced enough in circuit repair to be able to a) locate the on board buck converter stages and b) be both confident and competent enough to be able to isolate the onboard regulator at both the input and output and then inject the necessary correct voltage onto the output rail and check for short circuits using a current limited bench supply before hooking up a new buck converter to both the input supply to the original buck supply and then to the output of it taking great care to have set the requisite voltage first. Good luck! Follow Richard's EXCELLENT series of videos he is quite adept at fault finding and even if he makes errors occasionally you will learn even more as he realises, back tracks and corrects his errors!
Fantastic video. I had run into a bit of a rut trying to repair a switch mode supply of my own but your idea of just installing a separate 5v supply rather than trying to rebuild one component by component is genius. I'm sat here thinking why didn't I think of that? Looking forward to your next video now you have the bits for it. I imagine you'll be onto a winner with it.
Watching all the ATX power supply fixing videos, it seems there is a certain decision tree you subconsciously follow. It would be cool to have that on paper. The first step is checking 5V STB, if not: check for shorted output; if yes: test other voltages. You get the idea. Could you draw something like that?
To take this a step further, there could be probabilities of each decision branch listed. For example, it's very likely for a PSU to have faulty caps and very unlikely to have a failed transformer.
Great information I have a HP Pavilion slimline power supply. DPS 160QB cannot find a schematic. The 330vdc is present but no 5vstby or any rail voltages. Testing for short on connector I have Orange =50ohms, purple=206ohms, red =249ohms blue = 2.5kohms, yellow = 435ohms, grey = 1.3kohms, green= 1.7kohms do these seem ok? Not enough experience to know. Many thanks for your videos they are very helpful to a retired novice basically learning electronics to try and keep the old grey matter working.😊
Always wanted to learn how to fix this stuff, and I've pretty much been able to learn how to fix anything simple, but this is way over my head. As an extreme newbie, who can solder pretty well, I've learned a lot with these videos, but still have lot's of questions. \ I have a 550 PS that I've been trying to fix for a few days and just can't figure it out and was going to give up till I saw this video, since mine is almost identical to this one. After watching this, I found that the 5v transistor is definitely short, and though I know almost nothing, I was wondering if I could put a 5v power supply on the diode and bypass it. Well what da ya know!
Excellent video, although power supplies such as this hardly deserve a repair. A common sign of cheaping out can be found at the AC input, completely omitted all the filtering.
Can I make a suggestion. Do a video on some shotgun repairs that are likely to work. Ie replace all caps, test again. Replace all transistors test again. Replace fets test again. It might not be your preferred way but it would be quicker?
Good idea about using an external DC to DC converter module to replace an unfixable 5V standby circuit. Just need to find a point on the primary side where the rectified high voltage DC is dropped to a more sensible voltage (15V to 20V or something) for an after market step-down to 5V DC to DC converter module to tap from, which is plenty of them out there to choose from BTW, or you can simply DIY, that conforms to the ATX 5V SB minimum wattage requirement. On a side note, the supervisor IC (WT7520) may not be dead. Datasheet says that Power Good output is set high ONLY when there's no OVL/UVL condition for 3.3V 5V and 12V (pin 1 to 4) and because you took out the main switching transistors, therefore nothing is driving the main transformer, those voltages are obviously missing, right?
Hi getmefix I have the parts here now for this repair I was thinking of proving the idea of using a 5V PSU to replace the 'unrepairable' 5V STB and a small boost converter running from that PSU to generate the 16V-24V whatever is needed for the PWM controller and driver circuit to the transformer supplying base drive to the output transistors. Just to see if it can be done and how easy it is to implement such a repair or work-around
I don’t have voltage on vcc on the 5v controller chip. I tried to trace it but can’t tell where the voltage come from. The chip tda16822 just shows voltage coming after the rectifier and cap(sample circuit). Is there another circuit that gives power to some of those chips?
Hi i have a 500 watt powersuply if switch off the pc the powersuply goes on of and keeps on doing it and there is like a crackling sound in it every time itgoes on off eny help
my atx smps starts up fine, boots into OS, up to +/- 10min, then PC shuts off. After this I hear some slight short crackling inside PSU, and no standby which once lit up mobo LEDs anymore, power cycles a few times spinning fans briefly, then stops completely. I remove cables, come back after a while, it starts with standby voltage LEDs ok, story repeats itself...
Ahhh yes I was going to do a part two for this one but it got left on one side, I do still have it, plus some parts I ordered, and will get round to it now you reminded me.
Am I the only one that was screaming 'the glue! the glue!' when he couldn't work out why it wasn't coming out? Also, the pin by pin checking is a little laborious. If you wiggle the heatsink you'll quickly see which pins aren't moving! Great video though!
Whery nice video, can you made one with testing the stand by transformer, and the main transformer? what readings should be on primary and secundary side? and they have two legs on one but many on the other side, what should be the resistance on those pins? Thank you :)
You can't really test the transformer coils using a resistance meter, apart from if they are open circuit, or a short between two windings. One shorted turn on any winding will stop the transformer from working, generate low / no outputs, or possibly blow the driver transistor(s) but won't make any difference to the resistance measurement even comparing with a known good one
@@Watch__This_ There should be no open circuit windings and no shorts between windings. Some windings may have more than 2 pins, for example a centre tap. As I mentioned, these tests will find a faulty transformer but if the tests are good, it does not mean 100% that the transformer will be good. There could be shorted turns on a winding.
I have watched many of the previous videos and I notice that you have always put out a warning regarding the high voltage capacitor warning. Appreciate the warning to all noob electricians. Kudos.
I've repaired a number of video monitors with blown 5v internal supplies simply by bypassing them and fitting eBay buck converters instead ... Works a treat! A couple of quid and a few wires ... Job done. Cheaper, quicker & easier than buying individual components and repairing directly on the board. 👍👍👍
Can you do a video on that?
@@blackterminalsorry! Too much other stuff on. Plus, with the number and variety of different monitors around even from just one supplier, it wouldn' t help anyone unless they had the exact model.
You need to be experienced enough in circuit repair to be able to
a) locate the on board buck converter stages and
b) be both confident and competent enough to be able to isolate the onboard regulator at both the input and output and then inject the necessary correct voltage onto the output rail and check for short circuits using a current limited bench supply before hooking up a new buck converter to both the input supply to the original buck supply and then to the output of it taking great care to have set the requisite voltage first.
Good luck!
Follow Richard's EXCELLENT series of videos he is quite adept at fault finding and even if he makes errors occasionally you will learn even more as he realises, back tracks and corrects his errors!
Fantastic video. I had run into a bit of a rut trying to repair a switch mode supply of my own but your idea of just installing a separate 5v supply rather than trying to rebuild one component by component is genius. I'm sat here thinking why didn't I think of that?
Looking forward to your next video now you have the bits for it. I imagine you'll be onto a winner with it.
these are one of the best smps troubleshooting tutorials videos
Thank You!
Watching all the ATX power supply fixing videos, it seems there is a certain decision tree you subconsciously follow. It would be cool to have that on paper. The first step is checking 5V STB, if not: check for shorted output; if yes: test other voltages. You get the idea. Could you draw something like that?
To take this a step further, there could be probabilities of each decision branch listed. For example, it's very likely for a PSU to have faulty caps and very unlikely to have a failed transformer.
Great information I have a HP Pavilion slimline power supply. DPS 160QB cannot find a schematic. The 330vdc is present but no 5vstby or any rail voltages.
Testing for short on connector I have Orange =50ohms, purple=206ohms, red =249ohms blue = 2.5kohms, yellow = 435ohms, grey = 1.3kohms, green= 1.7kohms do these seem ok? Not enough experience to know. Many thanks for your videos they are very helpful to a retired novice basically learning electronics to try and keep the old grey matter working.😊
Same thing here friend, I really like this stuff, but it's not easy for this old mule.
Always wanted to learn how to fix this stuff, and I've pretty much been able to learn how to fix anything simple, but this is way over my head. As an extreme newbie, who can solder pretty well, I've learned a lot with these videos, but still have lot's of questions. \
I have a 550 PS that I've been trying to fix for a few days and just can't figure it out and was going to give up till I saw this video, since mine is almost identical to this one. After watching this, I found that the 5v transistor is definitely short, and though I know almost nothing, I was wondering if I could put a 5v power supply on the diode and bypass it. Well what da ya know!
Excellent video, although power supplies such as this hardly deserve a repair. A common sign of cheaping out can be found at the AC input, completely omitted all the filtering.
Can I make a suggestion. Do a video on some shotgun repairs that are likely to work. Ie replace all caps, test again. Replace all transistors test again. Replace fets test again. It might not be your preferred way but it would be quicker?
This was a perfect explanation of how that power supply failed.
Great exploring! Thanks!😅
Good idea about using an external DC to DC converter module to replace an unfixable 5V standby circuit. Just need to find a point on the primary side where the rectified high voltage DC is dropped to a more sensible voltage (15V to 20V or something) for an after market step-down to 5V DC to DC converter module to tap from, which is plenty of them out there to choose from BTW, or you can simply DIY, that conforms to the ATX 5V SB minimum wattage requirement.
On a side note, the supervisor IC (WT7520) may not be dead. Datasheet says that Power Good output is set high ONLY when there's no OVL/UVL condition for 3.3V 5V and 12V (pin 1 to 4) and because you took out the main switching transistors, therefore nothing is driving the main transformer, those voltages are obviously missing, right?
Hi getmefix
I have the parts here now for this repair
I was thinking of proving the idea of using a 5V PSU to replace the 'unrepairable' 5V STB and a small boost converter running from that PSU to generate the 16V-24V whatever is needed for the PWM controller and driver circuit to the transformer supplying base drive to the output transistors. Just to see if it can be done and how easy it is to implement such a repair or work-around
I don’t have voltage on vcc on the 5v controller chip. I tried to trace it but can’t tell where the voltage come from. The chip tda16822 just shows voltage coming after the rectifier and cap(sample circuit). Is there another circuit that gives power to some of those chips?
Hello Richard. Could you put in the description the link to the 2nd part of this video, please? Cheers, Pedders.
Hi i have a 500 watt powersuply if switch off the pc the powersuply goes on of and keeps on doing it and there is like a crackling sound in it every time itgoes on off eny help
my atx smps starts up fine, boots into OS, up to +/- 10min, then PC shuts off. After this I hear some slight short crackling inside PSU, and no standby which once lit up mobo LEDs anymore, power cycles a few times spinning fans briefly, then stops completely. I remove cables, come back after a while, it starts with standby voltage LEDs ok, story repeats itself...
53:41 - Can I check for a shorted turn using an inductance meter?
My power supply pg is missing what steps i should do?
Hi there just come across your video when trying to repair a dead ATX PSU, was there a part two to this video?
Ahhh yes I was going to do a part two for this one but it got left on one side, I do still have it, plus some parts I ordered, and will get round to it now you reminded me.
@@LearnElectronicsRepair Part 2???
Lol @@jonpeterson1447
Why sometimes the 3.3v is low to around 2.8v? 🤔
Am I the only one that was screaming 'the glue! the glue!' when he couldn't work out why it wasn't coming out?
Also, the pin by pin checking is a little laborious. If you wiggle the heatsink you'll quickly see which pins aren't moving!
Great video though!
Whery nice video, can you made one with testing the stand by transformer, and the main transformer? what readings should be on primary and secundary side? and they have two legs on one but many on the other side, what should be the resistance on those pins? Thank you :)
You can't really test the transformer coils using a resistance meter, apart from if they are open circuit, or a short between two windings. One shorted turn on any winding will stop the transformer from working, generate low / no outputs, or possibly blow the driver transistor(s) but won't make any difference to the resistance measurement even comparing with a known good one
@@LearnElectronicsRepair i am testing if there is a short, and if they are open line, and should be no conection between primary and secundary
@@Watch__This_ There should be no open circuit windings and no shorts between windings. Some windings may have more than 2 pins, for example a centre tap.
As I mentioned, these tests will find a faulty transformer but if the tests are good, it does not mean 100% that the transformer will be good. There could be shorted turns on a winding.
@@LearnElectronicsRepair thank you for the tips, and replay, nice videos, keep on going 👍👍👍
what if standby voltage is 5.6v? is it still okay?
While it will probably work, it is out of specification
www.oreilly.com/library/view/pc-hardware-in/059600513X/ch26s02s01.html
@@LearnElectronicsRepair what component causing the slightly higher voltage?
nice one sir
Thank you
I guess I'm dull of senses sometimes you gotta spell it out for ole tk.😊😮🤪🤠
I mean 5volts standby 😅