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.
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.
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
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.
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.
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!
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!
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!
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.
"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.
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.
First time i've seen a TVS diode present on these boards. I take it, the TVS diode got a large surge and just completely broke and went short, hence why there is a short between those two MOSFETS.
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.
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 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!
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.
I had old laptop from 1999 my son was using for the games on it. It went dead. Dead, dead, dead. It used those surface mount resistors with numbers on them for values. I found some next to power plug that said 0.0 on them. I took that to be a jumper of some sort. One gave no reading so I soldered a tiny wire across it and zam! It works again.
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!!
Thanks so much and your videos has helped me a lot and I were able to fix my Boss's Hp laptop - Probook as the Ram slightly came loose. And I had to open it up and pulled out Ram chip and replaced back into the board and then the laptop powered up and operated after experiencing screen freeze and only lights blinking within the keyboard area,,,. And now I need to fix my friend's Hp ProdID 250 G7 laptop but haven't seen one video of it as yet, and if someone able to show me and I would very much appreciate that,,,,. Regards, Charlie Jay, Wabag, Enga Province, PNG.
you inspire me and i think your job is pretty cool i have a similar problem but the super I/O (ITE chip) is getting hot and i dont have a voltage measure device
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.
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'.
I didn't learn anything but thank you so much for sharing your knowledge because I'm not interested in laptop repairing but on the other hand it is a big service for the people thanks again.
Really honest person,trying to explain what’s going on , after finding already problems. Thankful
The best teacher I have ever seen.
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.
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.
"Now I'm angry" ..the way you said it... Loved it! Very educative as well.
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.
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.
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
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.
That stupid zenner diode allows you to have a client =) your videos are fantastic, thanks for sharing your knowledge!!!
amazing talent you have sir.....I do repair things, but a laptop on this level is something I always wished....
Not stupid if they want the laptop to "break" easily...
Now that's not the answer were looking for
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
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
Long time no see Master. I've missed you.
Thank you for being such a good teacher!
very cool technician you are ,following since TOGO
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!
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!
I love all your videos.. I truly admire your generosity in sharing your valuable experience and knowledge.
Bless you!
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!
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.
keep sharing sir ..this a big help to all beginner like me ..to become someday like you sir
25:46 where fun part starts :)
This stupid I swear I get angry
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?
'This is moral thing'
Well explained.
Thanks Sorin
Amazingly intelligent man
I wish i was half as smart as you Sorin. Your videos brighten up my day!
Great video.I agree with your reasoning on the protection diode,which does not really protect but kills your laptop.
Wonderful, I love your videos man, so much to learn from, thanks a million.
Loved this one. thx so much for teaching me
you have to come together with Louis Rossman :)
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 !!!
You are the BEST Sir, it was same on my laptop, GREAT...!!! HP ab203TU ... I solved it looking your lesson.. Thanks again..
Always love your teachings Sir..thanks you come back...yes i believe hp got a problem as i experienced
i missed you man, the guy from South Africa.
very helpful to our friends ,, all of you are very kind
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
i have a limited electronic education but you explain so good i can understand .
"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.
He kinda looks like a grandpa teaching his grandchild with so much care and devotion. 💓💓💓
I should call you "Master"! It really helped me a lot. thx!
capo total la manera de explicar es sensacional soy de argentina y entiendo mas con vos que con los de mi propios idiomas
wow, best ever video on repairs you are truly a genuis🎉
That diode was put in place on purpose for planed obsolescence
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 good your point of view HP notebooks, Excellent contribution to knowledge
You are the best man love your'e video's I learn so much from you thanks man
they want you to buy only genuine Hp power supply that is why they put a zenior diode on the main power rail. Thnak you
First time i've seen a TVS diode present on these boards. I take it, the TVS diode got a large surge and just completely broke and went short, hence why there is a short between those two MOSFETS.
Welcome back Sorin we miss you
Thank you for the nice video
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.
Your all videos are full of information
Thank you sir
Love you
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.
A very very good explanation, you're the man Sorin !
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!
What a legendary master
Good job Mr. i m learning a lot
Great stuff. I have just bingewatched about 4 hours back-to-back. Thanks.
happy to see you Sorin :)
we missed you
Did the guy with the computer give you the shirt too?😂😂
Love your stuff man.
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.
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.
Am grateful for your videos it teaches me new methods
I had old laptop from 1999 my son was using for the games on it. It went dead. Dead, dead, dead. It used those surface mount resistors with numbers on them for values. I found some next to power plug that said 0.0 on them. I took that to be a jumper of some sort. One gave no reading so I soldered a tiny wire across it and zam! It works again.
Have HP laptop too, if it ever phuds out I’ll remember to check for this one
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!!
Sorin, they got you back just to fix all the unfixable ones. Admit it!
Wonderful, I like your enthusiasm
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.
Sorin, your shirt matches the laptop!
thanks mr sorin,you're my teacher.
i get a lot money from your videos
wow... you really cant understand how much you've been a source of inspiration to me. thanks Sir... i really appreciate this
This fail is present as well in the board model - day23amb6c0 rev c .... thanks for your time !!!
nice work sir I learn something in this video
This is a nice one, thanks for nice diagnosis. I am being inspired.
Thanks so much and your videos has helped me a lot and I were able to fix my Boss's Hp laptop - Probook as the Ram slightly came loose. And I had to open it up and pulled out Ram chip and replaced back into the board and then the laptop powered up and operated after experiencing screen freeze and only lights blinking within the keyboard area,,,.
And now I need to fix my friend's Hp ProdID 250 G7 laptop but haven't seen one video of it as yet, and if someone able to show me and I would very much appreciate that,,,,.
Regards,
Charlie Jay, Wabag, Enga Province, PNG.
Nice tips about how to diagnose a short on the board.
thanks for giving me an idea
you inspire me and i think your job is pretty cool i have a similar problem but the super I/O (ITE chip) is getting hot and i dont have a voltage measure device
This the best instructional video ever.
Welcome back ,nice to see you again.
started more liking for your lessons and a style of teaching too. very informative. Thanks
It’s a great repair again
And indeed the blue case is matching
thank you for New video sir.. Miss you
felicidades maestro y gracias por la leccion. see you next one thanks
Powersupply chatter just got a new meaning for me
I have a Omen by HP that just quit. This is interesting and I'm going to try and figure it out.
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?
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'.
Love the way you teach troubleshooting.
buna, frumos dom profesor, apreciez munca depusa.
You are the best...may God bless u and keep u..
Excellent, compulsive viewing ! The TV is dead !!! Great entertaining show !!
27:00 culprit is unnecessary diode
Wow this is like a magic its work for me thank you sir🙌🙌🙌🙌
Hope you had a nice holiday Sorin, I was wondering where you was, I missed your videos big man 👍🏻
Your a flipping credit to watch. Unreal. Good luck and health to ye. Lorcan here in Ireland
I didn't learn anything but thank you so much for sharing your knowledge because I'm not interested in laptop repairing but on the other hand it is a big service for the people thanks again.
I'm not interested in laptop repairing !! so why are even watching ? sorry but seems stupid comment and doesn't make sense
@@Customer22374rt - Sometimes people enjoy watching people doing things that they are no good at.
...it is a short, but not very short. Loved that
Thanks for the video. Gonna find my bad diode.