That's how a simple fault can piss all over your electronics knowledge & experience
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- เผยแพร่เมื่อ 28 พ.ย. 2024
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Reverse polarity protection diode was doing its job and because the positive and GND were swapped, the diode was forward-biased whenever the adapter was connected, essentially shorting positive to GND. Unplug the connector and the "short" was suddenly gone, so the adapter restored its output. Measured the connector with the multimeter and there was no dead short, since you were only seeing a diode junction there. Good find - can drive you nuts !
The clue was @ 9:25 you measured +12V from the charger & @ 10:00 you measured -12v from the adapter, I enjoyed the video. Actually I watched it twice.
I saw it to. it was -12
Yup send the - voltage when he measured the adapter cable.
😀😀😀😀😀
I feel grounded after this video.
You had it showing -12V several times and saying it had 12V while I was screaming at the screen and pointing at the minus sign. 🤣
My understanding is this:
Their original adapter probably died and they replaced it with wrong polarity device.
Input diode started melting due to wrong polarity, charger short circuit protection kicked in.
Bios locked/corrupted due to Sorin's rapid and incomplete power off/on cycles using power supply.
Agreed
@Mirko, the new power adapter has good polarity,
you would buy a duplicate as you propose.
What you need, in fact just the 1€ connector adapter with right polarity 9:37
I have never laughed this much on any other tech video.. I am dying..😆😆😆😆😆😆😆😆😆😆😆😆
He had me at POS computer, and I wasn't thinking point of sale.
Great stuff. From past experience I learned to never assume anything and only trust what the customer says after you've verified it.
Great work as usual... This is why its important for the shop to ask more questions, it would have saved time (and their cost)
Thanks for the video and lesson! Its often when there are two faults and you are looking for one that you get trolled.
I did think about a possible centre negative. It could be either the power supply or the adapter that’s been incorrectly replaced.
Lovely to see a thumbnail from back in the day. 👊🏼
I knew that cable was bad but resetting the bios would have stumped me. I do understand why you did though,...it was bound to be corrupt or frozen. Absolutely love you tackling all things electronic. Boundless learning ❤
The customer said it booted when they injected 12v (and if they could do that why didnt they figure such a simple issue) so why would the bios be an issue??
At 10:24 you have a voltage drop of -0.6 (diode) and I was convinced the input diode was reverse soldered because of the obvious meddling in that area 😅
Well done Sorin. I was ahead of you on that fault.
I also wasted a lot of time fault finding a connector just like that one which was connecting video, and audio left & right channels to a video capture card. No video, and only one audio channel working. Same fault, The plug fitted better upside down than the proper way up.
Very good, Positive ground, never would have thought it!
Nice to see when you work on a device other than a laptop. Wow, what a crazy fault! Never would think of that.😖 I would have called it a POS for a different reason.🤣 Outstanding troubleshooting.👍
Did you figure it out before me? :D
Yes i did, from like in the middle of your video but im still doubt it until you figure it out.
The moment you found out the ground wasn't going to ground on the adapter I knew the problem was within the adapter, but I didn't know why. We need those kind of faults every now and then to keep us humble.
you missed the " - " sign on multimeter at first measurement,.... i wait 20 minutes to see when you realise the reverse polarity .
Yes
You’re measuring OCV with the PS unplugged. Under load the voltage drops because there’s not enough current from the PS to supply the connected load. Since there’s no short on the input, I’d say you have a faulty supply.
Good job hanging in there not quitting
I saw the thumbnail and thought you were going to be in the shop. I miss that old atmosphere in your videos.
I like all your video's Sorin. Thanks for sharing as always!
Classic center negative confusion issue. You don't see these often. Great video Sorin!
Ya looks like they bought a center positive adapter cable which flipped the output pins around.at the output plug compared to what the POS required.
Hello🤝 I also had such a situation once in the First Austria console where the poles were changed plus and minus, good job👍👍👍👍👍👏👏👏👋👋👋👋
One of the first test I do for any repair, is to check the ground, and if it is positive or negative.
It is an heritage from my first days, on hybrid devices (build with vacuum tubes AND transistors, usually all PNPs),
This check would have identified the reversed power supply after a couple of minutes at most...
you are a genius
Brilliant fix Sorin, when you were messing with the adapter I guessed it was the fault, been caught out before like that thanks 😊
Minute 7:30, checking input voltage shows -0.56V! That's a negative voltage, and the leads on the multimeter are in the right order (red to plus, black to ground).
This voltage can hint a protection reverse polarity diode FWD voltage drop, exactly on the input power jack...
From that moment onwards, that was just entertainment... 😂
Love it! I always wait for WEEE HAVE PICTURE!!!
This is why it is important that customers tell repair shops everything.
25:46 best moment in every video ☺👍
in veata mea am vazut multe. da ca tine in prima oara, este ceva increDibil.🤣cred ca voi realiza un video.
The plus is no ground😊😊😊
You can see the dent in the adapter sleeve has to align with the slot on the inner plastic on the input but easy to miss because of the misleading slot on the metal outer sleeve on the input.
i swear these types of puzzles should be preserved so other puzzle solvers enjoy them, it's so stupid it's funny but at the same time you just want to flip the table 😂
haha one of those cases when we almost lose logic because of some of the assumptions that appear to be so obvious :) Thanks Sorin for this excellent video!
Well, that was one the most stupid problems I had ever seen, imagine a simple reverse polarity due to a non-standard cable could take half an hour to figure it out! That's nuts. 😂
At 7.35 minutes I noticed the meter was showing NEGATIVE 0.6 Volts, as somebody else has stated, a protection diode is conducting due to reverse polarity of the psu.
Lucky, never had a job like that, even if you can't fix they pay! Honestly surprises me every time.
Looks like a polarity converter/adapter - I had to buy one for a Casio Keyboard the other week as the centre pin was ground and the replacement charger I had to buy the centre pin was positive.
I really thought it was the female PSU connector on the board that was defective.
Maybe they didn't swap the adapter, but they did swap the charger/PSU. Some of them are inverted (plus outside the barrel, negative on the center pin).
Nice one!
Great video, mate. You assumed that the polarity of the connector was ok. But it was reversed. Assuming in electronics is never good.👍👍
Swap positive and negative inside the ac adapter. Much better than plugging the connector upside down into the pc.
And rub out the positive/negative designation on the ac adapter ....... and engrave new positive/negative orientation.
That way it won't be doggy work plugging in cables upside down.
From now on, I will check ground and plus first. Thanks
Well done!
13:53 I think this adaptercable is not the original part.
Indeed, lots of wasted time due to customers not telling all info. But thats always how it goes… As long as you charge per hour it doesnt really matter
спасибо ржу. причино следственные связи как что то потусторонние, с лицом загадкой
14:59 and you measure MINUS 12V.
This was a really tricky one Soren.😊
Tough one Sorin. Great job.
😀😀😀😀😀
Congratulations from Portugal 🇵🇹
seen some of this symptoms from green corrosion of stranded copper wires inside ...seen some cases of green corrosion (sometimes pulvorized stranded copper wires in solar panel wires because of high current.....the reason sometimes I don't like stranded wires but it depends on where to use it.
Great repair and repair man 👍
That's crazy, well done.
I was very confused about what "resetting the BIOS" could possibly mean. I think what that jumper actually does is "clear the CMOS memory", right?
Sorin, please, reduce the volume of the beep when you're working with the multimeter. It's too loud on phone speaker.
Good teacher😊
I knew from the second i saw a 4 pin proprietary power connector that the problem had to do with that. Ive similar things happen with uncommon connector, lik ones where there's a switch integrated into the connector so checking continuity when its not plugged leads to false conclusions or when extra pins require a pull up or down or interface somehow with input polarity protection. And ur lucky that connector was an adapter because usually its an uncommon connector u dont hav and u don't have access to the pins and u can't cut the cord to check cause it's the customers only one
Good job mate 👍
Oh Sorin - I was screaming at the screen from 1 minute in! Ive been repairing epos for 45 years lol there are 4 pins - 2 shorted pairs. on some the shorted pair run parallel to the flat side of the charge plug and others the shorted pair run perpendicular to it.
I also know you have a customised version of the software - called ICR touch, if you look very closely in one of the top corners, theres a pink line as its been edited in paint - ergo I know that that terminal originated from the west midlands company based in West Bromwich and the guy that edited the blue background has now moved to Ireland. the 4th line down that you are covering with the paper is a phone number ending 5566? am i correct? If you need any help with parts or programming for that (i think its a titan 360 but there are several named models based on that chassis)
AND SUNDAY IS SUPPOSED TO BE MY DAY OFF LOL
Thank you :)
lol, nice one for a sunday. My day started amazing thanks to you Sorin. If it came to me i think i would like to change that charging port with a female socket which will fit that adapter so no one will confuse in future :D
To me perhaps the power supply was wrong and should have been tip to ground ring to power, but plugging in the adapter the other way was a solution(and perhaps it was a tighter fit that way so won't fall out so easily? )
POS have un conventional connection. the four pin connection looks exactly like Toshiba Qosmio X300 ac chargers , I know because I have one. the Voltage for the POs is 12v unlike the regular laptop is 19V.the reverse conection of the four pin adapter just to make it hard to use a regular 4pin charger beside of course the Voltage.
What a fascinating problem.
Is making sense for voltage to drop if the wires ared skrewed and on load they drop connection ...
Thanks for the video I watched it for a long time but I didn't understand anything and I was trying to understand but you go faster 🇹🇿 but I can say thanks and I still waiting for another
If you are confused sorry I'm not good in English
Assumptions... As the punchline of the old joke goes: "If I were you, I wouldn't start from here".
OMG this is crazy, probably an hour or more for a reversed plug?!!! and with who? the master?!
I noticed something funny when you applied power and measured between the mosfet and ground and you got 0.60-ish volts. A diode drop. I thought someone replaced the protection diode backwards.
Excellent Saturday night comedy programme!
That is what we used to call a "Density Problem" in the shop. LOL Just make it an AC supply, then no problem !
I was wondering why you didn't connect your power supply to the short connector, could have helped point in the right direction.
Electronic repairs by Ray Liotta. 😉
I’ve experience and at 16:82 I’m wondering what the flip is going on…OK at 19:41 I got it, it the wrong bloody polarity.. phew 0.5V one diode drop.That reworked component is a diode and it’s in backwards across the 12V rail.
U missed the minus sign 😅 but how did you fix the frozen bios?
Hi Sorin, i don't figure it before like that... but sometime the swap positive exteranl & negative central PIN..... must look every time at PSU specifics.... good job i work few years for the GDO big distribution installing POS & Antitheaf and never happened me... Please replay to my ask on e-bay UK thank for the lesson bye Francesco Timpano from Florence Italy
I did, in the morning
Thank Sorin, i look in e-bay...@@electronicsrepairschool
Thank Sorin...
@@electronicsrepairschool
24:23 a mirror under the screen will help
What about the input connection?
Thank you, sir, for an interesting video. 😊
Be a while since seen that issue
Buyer beware kinda of thing.😅
Some of this type psu connector also output 12v and 5v.
It is a bad time on technology, windows 7 and so on product keys to windows 10 no longer work. I'm all for saving laptops from landfill, unless it's a 7th gen, anything below is done
This is why I bought an Eload.
"this is so simple. I don't get what's not to udnerstand"
after 3 minutes
"I am so confused"
ahaha
Can you please tell me the model number of this device ?
It looks like a built in screen in a mini computer.
I would like to get one of these. It has 2 serial ports on the motherboard and I need a computer with 2 serial ports
Thank you
good job bro love the videos
Hello, do you work in the UK?
I had a Dell charger , measures 19V , plug in .. no power & doesn't charge. Drove me crazy until I realized the male plug is bent.. straight = good but bent = dead. Cut open .. disconnected wires ! and I was checking the board !
Sherlock Sorin.
Something similar happened to me with a Dell charging connector with the white charging pin being grounded. 🤣🤣🤣🤣🤣🤣🤣🤣
27:16 See, that´s why many technicians are smarter than physicians!
I tell you a joke about it: The veterinarian goes to the physician because he feels sick.
So the physician asks: "Why are you here, what causes your discomfort?"
Then the veterinarian replies: "You know, it´s easy that way."
Yeah my father killed a HDD docking station 2 weeks ago with a 12v PSU with - on the inside and + on the outside of the plug….
When I saw the adapter I suspected it was upside down because it's not original
@ 10 mins you had minus 12v not plus 12v there are 2 versions of those adapters that have a different pin out where it plugs into the computer.
This type of device is really EVIL. The software requires this exact special motherboard otherwise it doesn't work. This is how current gen PC-based arcade games are now too. When the board dies from years of accumulated dust and moisture it's game over permanently unless that exact motherboard can be repaired or replaced with the exact same motherboard. Most of the time the board rots out and is beyond repair and the manufacturers know that. These devices have a forced limited life designed into them. As a result this has created a whole new industry of hackers that crack and modify software to get around motherboard type limits and sell these services for very high prices. It's all very sad and is only going to get worse in the future.
one of my favourite video
so next time check the bios and flip cord upside down lol 🤣🤣🤣🤣
Thank you for give me good hope for all ❤️use What se have 🥰🥰🥰
+/-? LOL Done it myself. You don't look for a fault that shouldn't be there. WPIB (Wrong Part In Box).
I think it all begun with a frozen BIOS and because of the not starting thingy they thought it might be the PS and then they added the second fault...
That was confusing fault🙄😀
Yeah classic center negative plug. It's a common mistake by amateurs to not check the polarity of the plug when replacing an AC adapter. Sega Master System has the same center-negative plug.
Early SEGA power adapters came from Yamaha parts bin due to existing partnership and those were center negative because guitar pedals are center negative, so most electronic music instruments of the era were center negative as well.
Doh, they replaced the PS with the barrel jack with a reverse polarity PS - lol -.