like MOSFETs, Zener diod is almost certainly part of the charging chip design template. Most of the manufacturers implement reference design instead of inventing their own weel. The problem with input voltage protection is that both MOSFETs could be shorted by voltage spike of a malfunctioning power supply. If it builds up a high-frequency AC ripple, it may be overseen by ACDET regulator but it will still blow insulator in MOSFET. in this case, you have uncontrolled DCIN going directly into the main power rail which is always a bad situation. Zener diodes are used on every single HDD as an over-voltage protection fuse - it gets blown very fast and it shorts power rail to the ground. Think of Zener diodes as an over-Voltage fuse. Since you did not replace the Zener and customer will use the same PSU, this laptop might come back at some point and I guess if it will, it will come with a blown cap or VCORE MosFET.
Hi @@mudathirs as far i can remember, i did change the diode cause i i was following strictly the vid, by chance i had another motherboard hp with me which i used as a donor, anyway Aliexpress can provide you the whole MOSFET and DIODE you need, but watch comments first to get the best quality, unfortunately many fake components. Good Luck
In my PSU designs I use suppressor diodes to protect from spikes, when they fail, fail short and burn out the fuse, so the rest of the board is safe and doesn't stress the charger or whatewer the power source. HP really should put some kind of fuse to the power rails. EDIT: if something goes wrong with the charger or wrong charger plugged in tantalium capacitors blow up pretty agressively. My guess they use max 25V components.
It's not zenner diode, it's reverse polarity protection. See it's pd9, not pz9 and the symbol shows a diode. That's why it is there for reason and not stupid.
Subbed and Thumbs up! Thank you so much for this! I was a repair engineer _Once_ and I still like to think that I can tackle most things but I was presented one of these in a very similar scenario, with the exception that the charging light comes on and it will charge the battery but when the power button is pressed, lights (but no screen) come on briefly; fan spins briefly then everything goes quiet, leaving only the charge light on. PSU is fine but *not* original. One of my excuses to not attempt something like this is that I don't have a Scope or re-ball facilities but you prove the contrary, using tried and tested basic equipment to repair things that would otherwise be 'beyond economical repair' by smaller companies and astronomically high priced repairs from manufacturers.
That part you were pointing out is actually a TVS diode (transient voltage suppressor) marked as "IV". You can look at it's specifications under it's equivalent being SMAJ20A tvs diode. It was a bit tricky finding it as either new semiconductor devices do not have a standardized marking code or, that (somewhat imperialistic) companies have their own marking code which at times do not even correspond to their own data books.
Now if these diodes are shorting to ground on over voltage then why would it not work correctly again when the over voltage is gone? I suppose that this diode was damaged. Permanently shorting to ground.
31:05 haha what is that someone put coin in USB port ? :O will that make laptop dead ? Respect! i learned so much from you and every day learning working with laptops 20 years and still every day I learn something new from you ! God bless you!
It may be a Transil diode called also TVS (Transient Voltage Supressor). It is used to protect against overvoltage. It shorted itself but protected rest of the components. In some cases transil can even protect against catching fire or explosion of Lithium-ion batteries.
Yes, it may have been a TVS diode doing its protection job correctly. That TVS may have been under-rated, or else a massive voltage spike appeared on the line.
The truth hurts. Sometimes when the baby is ugly you have to call it ugly. You cant fix what you don;t know, or accept in this case, is a broke system. FIX IT HP! ;) lol!
now I am going to look for zener fusible diodes right beside a capacitor....ACER ASPIRE 5333 water came out from ceiling it got poured and now hard to think more possible solutions. Thank you for sharing another idea!
I think its a TVS diode. A transient voltage suppression diode. It will short if the voltage reach its limit and does not recover from short anymore. I found one in a Western Digital Hard drive and its the same problem, the area where it was located we're charred/burnt.
John Price please recall that I did say it’s common practice. Inline TVS between FETs is plainly confusing to me logically. I place transient suppression only on connections where hands touch or near and between power supplies to the logic circuits, to protect against ESD. I must be doing something right since my designs do pass UL.
Fascinating! Thank you! As an application software support programmer, I find similar stupid things that programmers do in their programs. At least half or more of the programmers have no business writing programs. 90% of programs are terribly unstructured, disorderly, and inefficient. 10% of them are quite elegant and are a pleasure to read and follow along. The "logic" in circuitry is very similar to the "logic" in software, and most of the time, there are problems with insufficient testing and a lack of consideration for the end user's perspective.
I Recived this laptop on my shop same day this video was Published, and you know what? Same problem, i think i owe at least a Coffee to Sorin! :D THanks!
If the Zener diode wasn't there you would have a much larger repair job. Yea the Zener killed the laptop but it prevented damage elsewhere. The zener diode is probably there to meet some safety agency requirement.
There are supressors or MOVs which are designed especially for surge protection. Zener diodes are not really suitable for the task. Not in this power range. On a low power rail maybe, or on an I/O line, it is.
I have this exact laptop and for some reason it wont switch over to battery when you pull the AC. Its driving me insane. it also takes forever to start up when battery installed but remove battery and everything is good. Replaced the battery and the problem remains. please can you advise what it could be?
Very good video Sir. This is what is meant by "Inbuilt Obsolescence". These are crafty marketiers doing this on purpose so people will have to keep buying their products. And you are correct. They are not very intelligent humans,.. because they will alert people to not buy HP products. I had bought a HP Prodesk 600 G3 & 13 months after buying, the power supply shorted! First time a power supply shorted with me. When I checked the price of the replacement power supply, Canadian $99.00 + 13% tax!!
Hi can any one help me i have a linksys router ddwrt30x. With bad MMC IC and when you power it just blinks i tried to flush new firmware with ttl serial cable and it does half of job and when it get to MMC chip it hangs there it can not read or write to it. Any help would be greatfull
Sorin I wanna know something. Now whoever is sending you those laptops to you for reapirs, ( you said its from another shop) are those people or that guy not watching your videos and learning to troubleshoot? Get my point? By the way thanks so much once again. Love. Good luck. 😊 You are a man of 'heart'.
Hp doesn`t manufacture this board.It is not their fault.It depend from manufacture like Compal Quanta Inventec Clevo....They also manufacture for other brand,they put their design.Every manufacture has they design and for example Compal make board for hp lenovo and dell...Only except samsung and sony make they own.Same thing with bios Hp doesnt make them it make other company like phoenix....Sorry for my bad english.Greetings from Bosnia.
That's great for HP, many people will just buy a new one, other try a repair and will not succeed, so at HP they think they will sell another laptop ..... what they forget is that many will not buy another HP and go to other brand...!!! Great video.
sorry that's not a Zener diode. Zener diodes are mainly used as basic voltage regulators and are connected in reverse polarity mode. in this case the diode is there to protect against reverse polarity. it protects the power rail by shorting itself.
"Stupid diode" is subjective. For the manufacturer it is smart because it sets up the conditions that would cause someone to go out and buy another computer; ensuring another sale. It's called planned obsolescence.
That diode is meant to make a consumer either bring the laptop to a technician, or (better for them), make you buy a new laptop. When you removed the diode, did you leave that open? You didn't have to bridge that circuit or replace the diode with another one? It looked like you left it open. I have an HP, and if I ever need to remove the diode, that would be good to know.
what a strange design ? i safety device that leaves you with a dead laptop ?? given that your have 2 mosfets whos job is to cut the power if there are problems.............would you not design the power input to detect an overvolt situation and use the mosfets to cut the power ?...........with power being restored when the input voltage returns to normal ??? good video :)
Laptop was used with a non original PSU. The original PSU has a fast blowing fuse, the idea being that a high enough voltage to cause the zener to conduct will cause a high current condition and blow the fuse in the PSU before the zener can burn.
@@incandescentwithrage Well yeah, that'd be the way you or I would do it, but the people making the laptops are building in deliberate fail points. It functions, but designed to penalise the use of a non standard power supply. They of course want people to buy an expensive original from them, not a $5 generic from Walmart.
I think the way you work is slightly different from me, I wouldn't plug a power supply directly to the motherboard, if the voltage is being dragged down, the power regulators are the first thing I normally check for shorts etc..
Really honest person,trying to explain what’s going on , after finding already problems. Thankful
The best teacher I have ever seen.
"Now I'm angry" ..the way you said it... Loved it! Very educative as well.
like MOSFETs, Zener diod is almost certainly part of the charging chip design template. Most of the manufacturers implement reference design instead of inventing their own weel. The problem with input voltage protection is that both MOSFETs could be shorted by voltage spike of a malfunctioning power supply. If it builds up a high-frequency AC ripple, it may be overseen by ACDET regulator but it will still blow insulator in MOSFET. in this case, you have uncontrolled DCIN going directly into the main power rail which is always a bad situation. Zener diodes are used on every single HDD as an over-voltage protection fuse - it gets blown very fast and it shorts power rail to the ground. Think of Zener diodes as an over-Voltage fuse.
Since you did not replace the Zener and customer will use the same PSU, this laptop might come back at some point and I guess if it will, it will come with a blown cap or VCORE MosFET.
I have repaired my HP Pavilion 15-n225sf , i can't believe this, you are... a master, and i'm as far to be skiled as you are, Thanks thousand times.
@@totoasia i have a pavilion 14 x360 and I cant find the diode, would you be able to assist me?
Hi @@mudathirs as far i can remember, i did change the diode cause i i was following strictly the vid, by chance i had another motherboard hp with me which i used as a donor, anyway Aliexpress can provide you the whole MOSFET and DIODE you need, but watch comments first to get the best quality, unfortunately many fake components. Good Luck
In my PSU designs I use suppressor diodes to protect from spikes, when they fail, fail short and burn out the fuse, so the rest of the board is safe and doesn't stress the charger or whatewer the power source. HP really should put some kind of fuse to the power rails.
EDIT: if something goes wrong with the charger or wrong charger plugged in tantalium capacitors blow up pretty agressively. My guess they use max 25V components.
Happy return teacher, your classes are greatly missed; thanks for the experience and tips, greetings from South America.
You chose the HP because the color matched your shirt.
Thanks for today's lesson.
i said the same think before reading your comment i swear hhhhhhhh
That made me laugh. I had to blink twice 🤣
Weirdly enough it's how people buy HP's
Bloody cheap.
It's not zenner diode, it's reverse polarity protection. See it's pd9, not pz9 and the symbol shows a diode. That's why it is there for reason and not stupid.
Not stupid if they want the laptop to "break" easily...
Now that's not the answer were looking for
Thank you for being such a good teacher!
I like your way in analyzing and solving each case you come up to, i am addicted to your videos, a week without them OMG
That stupid zenner diode allows you to have a client =) your videos are fantastic, thanks for sharing your knowledge!!!
Subbed and Thumbs up! Thank you so much for this! I was a repair engineer _Once_ and I still like to think that I can tackle most things but I was presented one of these in a very similar scenario, with the exception that the charging light comes on and it will charge the battery but when the power button is pressed, lights (but no screen) come on briefly; fan spins briefly then everything goes quiet, leaving only the charge light on. PSU is fine but *not* original. One of my excuses to not attempt something like this is that I don't have a Scope or re-ball facilities but you prove the contrary, using tried and tested basic equipment to repair things that would otherwise be 'beyond economical repair' by smaller companies and astronomically high priced repairs from manufacturers.
Did you fix it sir?? I have the same problem
That part you were pointing out is actually a TVS diode (transient voltage suppressor) marked as "IV". You can look at it's specifications under it's equivalent being SMAJ20A tvs diode. It was a bit tricky finding it as either new semiconductor devices do not have a standardized marking code or, that (somewhat imperialistic) companies have their own marking code which at times do not even correspond to their own data books.
Now if these diodes are shorting to ground on over voltage then why would it not work correctly again when the over voltage is gone?
I suppose that this diode was damaged. Permanently shorting to ground.
Long time no see Master. I've missed you.
amazing talent you have sir.....I do repair things, but a laptop on this level is something I always wished....
I love all your videos.. I truly admire your generosity in sharing your valuable experience and knowledge.
Bless you!
25:46 where fun part starts :)
This stupid I swear I get angry
very cool technician you are ,following since TOGO
I so much love the way you teach... I wish I could be your student.
You kind of already are if you're watching his videos. ;)
Can I have your number
31:05 haha what is that someone put coin in USB port ? :O will that make laptop dead ? Respect! i learned so much from you and every day learning working with laptops 20 years and still every day I learn something new from you ! God bless you!
keep sharing sir ..this a big help to all beginner like me ..to become someday like you sir
'This is moral thing'
Well explained.
Thanks Sorin
Welcome back Sorin we miss you
Thank you for the nice video
wow, best ever video on repairs you are truly a genuis🎉
It may be a Transil diode called also TVS (Transient Voltage Supressor). It is used to protect against overvoltage. It shorted itself but protected rest of the components. In some cases transil can even protect against catching fire or explosion of Lithium-ion batteries.
Yes, it may have been a TVS diode doing its protection job correctly. That TVS may have been under-rated, or else a massive voltage spike appeared on the line.
Thinking maybe the PSU failed and sent a voltage surge to the laptop?
Amazingly intelligent man
I wish i was half as smart as you Sorin. Your videos brighten up my day!
i missed you man, the guy from South Africa.
A very very good explanation, you're the man Sorin !
Always love your teachings Sir..thanks you come back...yes i believe hp got a problem as i experienced
Wonderful, I love your videos man, so much to learn from, thanks a million.
Your all videos are full of information
Thank you sir
Love you
I should call you "Master"! It really helped me a lot. thx!
Thank you Sorin, I imagined the fault before you show it just because I saw your other videos before ...
You're a master in the Power fault !!!
Great stuff. I have just bingewatched about 4 hours back-to-back. Thanks.
Loved this one. thx so much for teaching me
HP designer and his manager disliked the video!
The truth hurts. Sometimes when the baby is ugly you have to call it ugly. You cant fix what you don;t know, or accept in this case, is a broke system. FIX IT HP! ;) lol!
capo total la manera de explicar es sensacional soy de argentina y entiendo mas con vos que con los de mi propios idiomas
i have a limited electronic education but you explain so good i can understand .
Did the guy with the computer give you the shirt too?😂😂
Love your stuff man.
Very good your point of view HP notebooks, Excellent contribution to knowledge
happy to see you Sorin :)
we missed you
You are the BEST Sir, it was same on my laptop, GREAT...!!! HP ab203TU ... I solved it looking your lesson.. Thanks again..
You are the best man love your'e video's I learn so much from you thanks man
now I am going to look for zener fusible diodes right beside a capacitor....ACER ASPIRE 5333 water came out from ceiling it got poured and now hard to think more possible solutions. Thank you for sharing another idea!
Thank you Sír you are a great human being for share all of this. I wish I have the 5 dólares to joining your school.
I think its a TVS diode. A transient voltage suppression diode. It will short if the voltage reach its limit and does not recover from short anymore. I found one in a Western Digital Hard drive and its the same problem, the area where it was located we're charred/burnt.
correct...
TVS diodes commonly go on the ends of circuits and not between FETs. It’s more likely to be a zener diode.
@@lelmus3277 Zener diodes don't want to be in the main power bus, they are usually placed on the base/gate of a BJT or FET if I recall
@@lelmus3277 According to the circuit diag. the part number is P4SMAJ20A so we may have to agree to differ on this one .. Keep up the good work .
John Price please recall that I did say it’s common practice. Inline TVS between FETs is plainly confusing to me logically. I place transient suppression only on connections where hands touch or near and between power supplies to the logic circuits, to protect against ESD. I must be doing something right since my designs do pass UL.
Great video.I agree with your reasoning on the protection diode,which does not really protect but kills your laptop.
Thanks sorin for this new vidéo. all your videos are important, not because the device you repaire, but because of all the things you say.
wow... you really cant understand how much you've been a source of inspiration to me. thanks Sir... i really appreciate this
Welcome back ,nice to see you again.
thanks mr sorin,you're my teacher.
i get a lot money from your videos
Fascinating! Thank you! As an application software support programmer, I find similar stupid things that programmers do in their programs. At least half or more of the programmers have no business writing programs. 90% of programs are terribly unstructured, disorderly, and inefficient. 10% of them are quite elegant and are a pleasure to read and follow along. The "logic" in circuitry is very similar to the "logic" in software, and most of the time, there are problems with insufficient testing and a lack of consideration for the end user's perspective.
very helpful to our friends ,, all of you are very kind
I Recived this laptop on my shop same day this video was Published, and you know what? Same problem, i think i owe at least a Coffee to Sorin! :D THanks!
lol, no way!
Sorin, they got you back just to fix all the unfixable ones. Admit it!
Am grateful for your videos it teaches me new methods
Good job Mr. i m learning a lot
If the Zener diode wasn't there you would have a much larger repair job. Yea the Zener killed the laptop but it prevented damage elsewhere. The zener diode is probably there to meet some safety agency requirement.
There are supressors or MOVs which are designed especially for surge protection. Zener diodes are not really suitable for the task. Not in this power range. On a low power rail maybe, or on an I/O line, it is.
@@PHONE-LAPTOP-REPAIRWhat did I say that was disrespectful? Just stating what I felt was a reason for the diode to be there.
Wonderful, I like your enthusiasm
Love the way you teach troubleshooting.
what was that thingy you took out from usb port ??? 31:08 ???
He kinda looks like a grandpa teaching his grandchild with so much care and devotion. 💓💓💓
Hope you had a nice holiday Sorin, I was wondering where you was, I missed your videos big man 👍🏻
I have this exact laptop and for some reason it wont switch over to battery when you pull the AC. Its driving me insane. it also takes forever to start up when battery installed but remove battery and everything is good. Replaced the battery and the problem remains. please can you advise what it could be?
you have to come together with Louis Rossman :)
This is a nice one, thanks for nice diagnosis. I am being inspired.
This the best instructional video ever.
started more liking for your lessons and a style of teaching too. very informative. Thanks
Very good video Sir. This is what is meant by "Inbuilt Obsolescence". These are crafty marketiers doing this on purpose so people will have to keep buying their products. And you are correct. They are not very intelligent humans,.. because they will alert people to not buy HP products. I had bought a HP Prodesk 600 G3 & 13 months after buying, the power supply shorted! First time a power supply shorted with me. When I checked the price of the replacement power supply, Canadian $99.00 + 13% tax!!
Hi can any one help me i have a linksys router ddwrt30x. With bad MMC IC and when you power it just blinks i tried to flush new firmware with ttl serial cable and it does half of job and when it get to MMC chip it hangs there it can not read or write to it. Any help would be greatfull
Sorin I wanna know something. Now whoever is sending you those laptops to you for reapirs, ( you said its from another shop) are those people or that guy not watching your videos and learning to troubleshoot? Get my point? By the way thanks so much once again. Love. Good luck. 😊 You are a man of 'heart'.
God bless you for today’s lesson ❤️🙌🏽
Hp doesn`t manufacture this board.It is not their fault.It depend from manufacture like Compal Quanta Inventec Clevo....They also manufacture for other brand,they put their design.Every manufacture has they design and for example Compal make board for hp lenovo and dell...Only except samsung and sony make they own.Same thing with bios Hp doesnt make them it make other company like phoenix....Sorry for my bad english.Greetings from Bosnia.
Interesting. thks for the info.
That's great for HP, many people will just buy a new one, other try a repair and will not succeed, so at HP they think they will sell another laptop ..... what they forget is that many will not buy another HP and go to other brand...!!! Great video.
Only for PC experts this. My problem with a new HP laptop that wouldn't turn on was unplugging power , press power button for 30 seconds.
So where's your new wireless soldering iron? I recall that you were quite happy about it. Why are you not using it?
Hot air is probably easier.
Wow this is like a magic its work for me thank you sir🙌🙌🙌🙌
sorry that's not a Zener diode. Zener diodes are mainly used as basic voltage regulators and are connected in reverse polarity mode.
in this case the diode is there to protect against reverse polarity. it protects the power rail by shorting itself.
Sorin, your shirt matches the laptop!
thank you for New video sir.. Miss you
nice work sir I learn something in this video
the best sorin all over the world, thx too much 🌹🌹
"Stupid diode" is subjective. For the manufacturer it is smart because it sets up the conditions that would cause someone to go out and buy another computer; ensuring another sale. It's called planned obsolescence.
Yep.
buna, frumos dom profesor, apreciez munca depusa.
Your a flipping credit to watch. Unreal. Good luck and health to ye. Lorcan here in Ireland
That diode is meant to make a consumer either bring the laptop to a technician, or (better for them), make you buy a new laptop.
When you removed the diode, did you leave that open? You didn't have to bridge that circuit or replace the diode with another one? It looked like you left it open. I have an HP, and if I ever need to remove the diode, that would be good to know.
you typically don't bridge diodes, but especially this one, because its in parallel with the input of the laptop, so it will be a caboom :D
You are amazing man Thanks for o lot of hints and I recovered a HP Laptop coz of you.
Helpful video 👍
what a strange design ? i safety device that leaves you with a dead laptop ?? given that your have 2 mosfets whos job is to cut the power if there are problems.............would you not design the power input to detect an overvolt situation and use the mosfets to cut the power ?...........with power being restored when the input voltage returns to normal ??? good video :)
27:00 culprit is unnecessary diode
Laptop was used with a non original PSU. The original PSU has a fast blowing fuse, the idea being that a high enough voltage to cause the zener to conduct will cause a high current condition and blow the fuse in the PSU before the zener can burn.
Then the Zener should be on the output of the PSU, not after the first MOSFET of the motherboard. This approach still makes no sense.
@@incandescentwithrage Well yeah, that'd be the way you or I would do it, but the people making the laptops are building in deliberate fail points. It functions, but designed to penalise the use of a non standard power supply. They of course want people to buy an expensive original from them, not a $5 generic from Walmart.
And what do you think they'll do when you take in the laptop for repair? Replace the diode or replace the entire MB for a lot more money?
@@RJVBI get what you're saying but why are you directing that rant/question at me?
Excellent work!! Love your lessons.
You are the best...may God bless u and keep u..
Where to order the parts electronic?
DigiKey ?
What a legendary master
Thank you so much for today lesson!
felicidades maestro y gracias por la leccion. see you next one thanks
I think the way you work is slightly different from me, I wouldn't plug a power supply directly to the motherboard, if the voltage is being dragged down, the power regulators are the first thing I normally check for shorts etc..
Soren seems more brutally old skool IMO. I think he's fantastic. 😊
Well using your method, you just missed a faulty charging port. Recall that this came to the guy listed as a faulty charging port.