Familiar problem, didn't think I'd see this easy to fix fault twice in a row, but I'm not complaining. Looks like failed reverse-voltage diodes are a thing around here now.
apparently, the plastic cover is not just as a water damage protection, but also as a heat source pointer so we don't have to spend much time to hunt it with voltage injection. awesome repair Adam. ;)
Sometimes those diodes are not your standard schottky or generic type. Often companies will incorporate a TVS style diode that is designed to function as a standard diode in reverse bias mode, and will clamp (short) when over voltage is detected. In most cases these will clamp without a catastrophic fail and will generally fault a secondary internal circuit protection portion of the board that only a person with some electronics knowledge and a soldering iron can fix. I call TVS diodes a "Warranty buster"
I don't think this is reversed polarity diode. If the second pad is going to the power input pins of secondary power rails then it is and it wouldn't burn when you plug reversed charger it will just not let current flow the opposite way. If it is going to the negative plane then it is a TVS diode that protects from dc voltage spikes. TVS diodes have the following two main properties: 1) Clamping voltage window - usually starting a few volts above the rated voltage of the charger and a max clamping voltage which has to be lower than the max operating voltage of the buck converters feeding off of the main power rail. When they start conducting the excess power to ground they can only do that up to (2) 2) Max conducting power rating at max clamping voltage (usually 200w,400w,600w or 1000w) You can install a few lower power rated diodes in parallel but exact same model or a higher power rated one to prevent them from burning. They should be installed after a reversed polarity diode so they don't burn from reversed chargers. It is possible that some laptop manufacturers don't install a rp diode and count on the tvs one to fail short. If they fail open on reverse polarity - Bye bye motherboard.
So glad I found your channel. Lots of how to videos but very few go through the thought process and more importantly know how to convey the knowledge through the camera. QUICK QUESTION: How do you keep track of where the screws come out as some screws are different lengths etc and also do you keep track of what connector goes where before you disconnect. Thanks!
Experience... you get good at memorising screw and connector positions as you go over time. Connectors are often keyed and only go into the correct places, which makes that easier. Off-camera I'm often putting screws into separate piles for case, mobo, drive, etc. And in the worst case, take pictures as you go, showing where everything was as you removed it.
Why does it seem like a very large percentage of the laptop repairs are around short circuit faults ? They are fun to watch alo0ng with you, I usually watch on my long commute to work...
Hey there, I recently started watching your videos and I guess it will be my side hobby thanks to you 🫡. Btw @6:41 you should have removed the charger first and then attached the keyboard. You just got lucky not to get failed keyboard 😅
Does that oscillating voltage cause the DC - in jack to get hot as well? Thank you 🤓 I realize you didn't really go over the laptop info, but can (could) the CPU be upgraded? Thank you again
I am having same laptop I am getting short of capacitor in the backend of cpu and in other parts of the motherboard also when applying current the ic is getting extremely hot 🥵 my laptop not powering and no led I need help
Third party chargers. The universal ones, or just cheap-ass ones can be the wrong way around, or the wrong voltage - that's the main angle that this would protect from. Toshiba can either A) pay another cent for a protection diode or B) Tell the customer that their laptop went nuclear because they used a non-toshiba charger. Better to have a 'graceful fail' than something that might start smoking!
Hey Adam, Thank you very much, i had a great luck, i have the same model with the same problem which is evident, but i don't have nor i knwo where to find a reverse voltage diode that matches the laptop. where can i find one? thank you very much
Check ebay or aliexpress. You need a Schottky Rectifier Diode rated for 30v, in SMA size. Here's an example on eBay UK: www.ebay.co.uk/itm/192749145068
@@Adamant_IT Today i've sodered the smd diode and it's working. I really love what you do and i hope to become like you. If you ever decide to come to Canary Islands for a break give me a shout :) . I have a guest room as well with my sodering kit :P
You should look for some reverse diode which has a higher amp and volt max rating that the rating you are going to actually use. for example a regular notebook uses 19v 3.14a then you buy a 35v 6a reverse diode and you will be OK. You should, of course, check you are buying an smd diode that would fit there. It is explained in this video, and Adamant has a whole video dedicated to find replacement parts
I know i'm a bit late with this comment but some chargers do have reverse polarity maybe someone plugged and over volted or amped one into it .guitar foot pedals are often negative on the center pin but only 9-12 V DC but other appliances are some times the same (reversed polarity) if the plug fits could have happened. Or a dodgy made in china piece of crap charger.
I think the manufacture know all third party charger in this world is a crap. I have seen the charger come with positive outside with same DC jack and same volt, but not for all laptop. It design to specific laptop or devices.
You are incorrect in the function and nature of that diode. It is not a standard rectifier diode, it is a zener diode which is a form of voltage regulator. It is connected across the input BACKWARDS from a regular diode so that if the voltage goes above, say 20vdc, it will flow current to ground to prevent an overvoltage from reaching the system. I repeat IT IS NOT A STANDARD DIODE.
@@ivanuric1879 , I respectfully disagree. He is calling it CONSISTENTLY a reverse polarity diode, which would not be connected in paralell with the power input jack, but would be in series to prevent plugging in an adapter with the wrong polarity. THAT IS NOT WHAT THIS IS. This is a special kind of diode with a specific reverse breakdown voltage that shorts to ground if the breakdown voltage is exceeded. If you were to put a standard rectifier diode in its place you'd have to exceed 1000VDC or more before it will begin to conduct instead of the 20.5 or so the zener would start to conduct at. Further the rectifier is not designed to conduct in reverse and would quickly undergo RUD. (random unplanned disassembly. I.e. it'll blow.)
![Toshiba C55 No 3.3/5v rails [Fail] - LFC#216](/img/n.gif)
apparently, the plastic cover is not just as a water damage protection, but also as a heat source pointer so we don't have to spend much time to hunt it with voltage injection. awesome repair Adam. ;)
Sometimes those diodes are not your standard schottky or generic type. Often companies will incorporate a TVS style diode that is designed to function as a standard diode in reverse bias mode, and will clamp (short) when over voltage is detected. In most cases these will clamp without a catastrophic fail and will generally fault a secondary internal circuit protection portion of the board that only a person with some electronics knowledge and a soldering iron can fix. I call TVS diodes a "Warranty buster"
Spot on repair work. I really enjoy your videos, thanks for sharing your knowledge with the world.
You help me so much with improving my English! "hecking chonkers" will see regular use for sure!
reversed protection diode is for the universal laptop chargers that are out there that are not keyed for centred positive plugs
I don't think this is reversed polarity diode. If the second pad is going to the power input pins of secondary power rails then it is and it wouldn't burn when you plug reversed charger it will just not let current flow the opposite way. If it is going to the negative plane then it is a TVS diode that protects from dc voltage spikes.
TVS diodes have the following two main properties:
1) Clamping voltage window - usually starting a few volts above the rated voltage of the charger and a max clamping voltage which has to be lower than the max operating voltage of the buck converters feeding off of the main power rail. When they start conducting the excess power to ground they can only do that up to (2)
2) Max conducting power rating at max clamping voltage (usually 200w,400w,600w or 1000w)
You can install a few lower power rated diodes in parallel but exact same model or a higher power rated one to prevent them from burning. They should be installed after a reversed polarity diode so they don't burn from reversed chargers. It is possible that some laptop manufacturers don't install a rp diode and count on the tvs one to fail short. If they fail open on reverse polarity - Bye bye motherboard.
Yes, transil diode, had the same issue on an Acer netbook years ago.
So glad I found your channel. Lots of how to videos but very few go through the thought process and more importantly know how to convey the knowledge through the camera. QUICK QUESTION: How do you keep track of where the screws come out as some screws are different lengths etc and also do you keep track of what connector goes where before you disconnect. Thanks!
Experience... you get good at memorising screw and connector positions as you go over time. Connectors are often keyed and only go into the correct places, which makes that easier.
Off-camera I'm often putting screws into separate piles for case, mobo, drive, etc.
And in the worst case, take pictures as you go, showing where everything was as you removed it.
5:04 ‼ when this happened. I heard the Metal Gear Solid sound effect in my head.
05:11 Your reaction was so nice :) By the way your videos are so helpful. Thank you !
Why does it seem like a very large percentage of the laptop repairs are around short circuit faults ? They are fun to watch alo0ng with you, I usually watch on my long commute to work...
Have two of these boards stashed away somewhere. 😲 time to dig them up and check those diodes...
Don't shock 😅✌️✌️✌️nice one to you sir more videos 😉
Highlight of the show was when the plastic cover snapped back!
Apologies for giggling!
Hey there, I recently started watching your videos and I guess it will be my side hobby thanks to you 🫡. Btw @6:41 you should have removed the charger first and then attached the keyboard. You just got lucky not to get failed keyboard 😅
How many people jumped when the plastic went back into place? "me"
I jumped out my seat haha Was not expecting that 😅
Reverse voltage on newer laptops might be for safety regulations for some countries
Does that oscillating voltage cause the DC - in jack to get hot as well? Thank you 🤓 I realize you didn't really go over the laptop info, but can (could) the CPU be upgraded? Thank you again
how about changing 100% but Plug Out Charge laptop die, Dynabook r732/g, it's battery or board Sir ?
special thank you
I am having same laptop I am getting short of capacitor in the backend of cpu and in other parts of the motherboard also when applying current the ic is getting extremely hot 🥵 my laptop not powering and no led
I need help
Hello, is it possible to change processor?
why not a full brige rectifier to fix this?
How can someone apply reverse polarity with a charger?? Not the toshiba charger?
Third party chargers. The universal ones, or just cheap-ass ones can be the wrong way around, or the wrong voltage - that's the main angle that this would protect from. Toshiba can either A) pay another cent for a protection diode or B) Tell the customer that their laptop went nuclear because they used a non-toshiba charger.
Better to have a 'graceful fail' than something that might start smoking!
@@Adamant_IT It makes sense, thanks. btw reverse polarity protection was my first protection "circuit" i learned. :)
You can never have too much flux.
Hi do you repair motherboards?
Why fit it?
Maybe to make laptops break. Or me being too cynical?
Hey Adam, Thank you very much, i had a great luck, i have the same model with the same problem which is evident, but i don't have nor i knwo where to find a reverse voltage diode that matches the laptop. where can i find one?
thank you very much
Check ebay or aliexpress. You need a Schottky Rectifier Diode rated for 30v, in SMA size. Here's an example on eBay UK: www.ebay.co.uk/itm/192749145068
@@Adamant_IT thank you very much man i will let you kknow of my adventures :D
@@Adamant_IT Today i've sodered the smd diode and it's working. I really love what you do and i hope to become like you. If you ever decide to come to Canary Islands for a break give me a shout :) . I have a guest room as well with my sodering kit :P
5:10 that has happened to me. same exact reaction lol
WHERE CAN I BUY THIS REVERSE POLARITY DIOD FOR ** TOSHIBA SATELLITE 55D-C ** if someone can help me please? Thanks!
You should look for some reverse diode which has a higher amp and volt max rating that the rating you are going to actually use. for example a regular notebook uses 19v 3.14a then you buy a 35v 6a reverse diode and you will be OK. You should, of course, check you are buying an smd diode that would fit there. It is explained in this video, and Adamant has a whole video dedicated to find replacement parts
That was more like 2 micropauls of flux if you ask me
Great Fix
5:08 i got socked too 😂
I know i'm a bit late with this comment but some chargers do have reverse polarity maybe someone plugged and over volted or amped one into it .guitar foot pedals are often negative on the center pin but only 9-12 V DC but other appliances are some times the same (reversed polarity) if the plug fits could have happened. Or a dodgy made in china piece of crap charger.
Use Flux to desolder easy peasy.
I think the manufacture know all third party charger in this world is a crap. I have seen the charger come with positive outside with same DC jack and same volt, but not for all laptop. It design to specific laptop or devices.
I got scared 5:10
You should get thermal camera
You are incorrect in the function and nature of that diode. It is not a standard rectifier diode, it is a zener diode which is a form of voltage regulator. It is connected across the input BACKWARDS from a regular diode so that if the voltage goes above, say 20vdc, it will flow current to ground to prevent an overvoltage from reaching the system. I repeat IT IS NOT A STANDARD DIODE.
That is literally what he said, he just used didn't use the term zener diode. You're nitpicking and you sound very condescending.
@@ivanuric1879 , I respectfully disagree. He is calling it CONSISTENTLY a reverse polarity diode, which would not be connected in paralell with the power input jack, but would be in series to prevent plugging in an adapter with the wrong polarity. THAT IS NOT WHAT THIS IS. This is a special kind of diode with a specific reverse breakdown voltage that shorts to ground if the breakdown voltage is exceeded. If you were to put a standard rectifier diode in its place you'd have to exceed 1000VDC or more before it will begin to conduct instead of the 20.5 or so the zener would start to conduct at. Further the rectifier is not designed to conduct in reverse and would quickly undergo RUD. (random unplanned disassembly. I.e. it'll blow.)