I'm guessing the real cause is an aged electrolytic capacitor. The electrolyte can dry out over time causing a change in capacitance. Power supplies are the most common failure in electronics and electrolytic capacitors are a common reason for power supply failure.
There are electrolytic capacitors near where he was heating, and the capacitance of electrolytics can have a strong temperature dependence. He probably managed to heat one of the electrolytic capacitors, which happened to change its capacitance in the correct direction to make the circuit work.
Chances are the monitor would work reliably if all the electrolytic capacitors were replaced.
Edit:
I'm guessing the problem is C208. Section 10 of the LDO data sheet, linked in the article, talks about how stability is dependent on the output capacitor (C208). C208 has probably dried out, reducing its capacitance and making the LDO unstable. Heating was enough to make the circuit stable (for a while).
Further edit:
Predating my comment, "Gordonjcp" also called out C208.
> Power supplies are the most common failure in electronics
In over 35 years of troubleshooting gear and systems, my experience is that 90% (no exaggeration) of problems are bad cables.
It seems even worse, these days, with high-speed serial cables, running on razor-thin margins, and often with embedded ICs.
That's why, when the IT geek comes to your desk, they just rip out all your cables, and replace them with new ones, out of the shrink-wrap. They'll toss out a hundred dollars' worth of perfectly good cables, because they know the deal. They could waste an hour, trying to troubleshoot a problem caused by an intermittent USB C cable.
We had a 500W subwoofer amp just die on us one day. Since the replacement was going to be several hundred dollars, I figured I’d try disassembling it to see if I could find a problem.
Lo and behold, I saw three 1000uF caps that had leaked, one of which had a clear bulge on the top. So I ordered a bunch of replacements off Mouser, bought myself a soldering iron, and replaced all three. Worked like a charm!
I’ll never understand why even high-end equipment manufacturers wind up using crappy knockoff capacitors in their stuff. It seems like it’s just a failure waiting to happen. I guess they get to make good money on the support and service?
It's such a widespread phenomenon that there's an entire site (with good repair forums) about electrolytic capacitors causing failures: https://badcaps.net/
An old trick I learned from a tech who repaired CRT televisions was to test components by spraying them with an aerosol. If something was close to failing, the cold propellant would push it over the edge and you could target individual capacitors to identify which ones need replacement.
A few years ago, I got ahold of an old Samsung Syncmaster LCD that didn't work anymore. After replacing all electrolytic caps for around 2-3$, it worked like new again.
I had a computer that could only be booted with a hair dryer. I did not disassemble any parts, so I never got to know which exact part was failing, but a good 5-10 minutes of pre-heating with the dryer allowed it to boot.
I saved a monitor once that had a bad cap in the power supply— very satisfying and straightforward fix, like a $2 part and fifteen minutes of taking it apart and soldering.
When visiting China as a teenager in the early 90s, my brother and I decided to invest our hard-saved cash in a Micro Genius. This was a rip-off of a Super Famicom which I'd seen a Malaysian school friend play back home in Australia.
There's a photo of us smiling at the counter of a department store, handing over money. We bought a couple of multi-game cartridges. 190-in-1 and 27-in-1 or something.
We tested it in a Hong Kong hotel room, and briefly played a few games. Then imagine our dismay when we eventually got back to Australia and the thing wouldn't reliably load a game. We were blowing on cartridges and all that.
One day, we gave it a shot up in our non-A/C, second-storey bedroom. It was a 40 deg C day, so absolutely cooking upstairs. The console worked! The games loaded! We got to play an assorted of games we'd been eagerly waiting on.
We eventually decided it must be the heat and on the next day I can remember us taking it in turns with a hairdryer trying to warm the console or cartridge to get a game to start while the other person played. It might let us play for several minutes and then fail. Unfortunately, this trick didn't last for long and then the console was surpassed and the games no longer kept our interest.
30 years later, I still have the useless boxed console in my garage and can't bear to throw it out.
This is a really cute story. It might be really nice to fix it up and play it with your brother at Christmas (or other similar holiday) as a bonding fun time.
> A common issue with these types of components is that the quiescent current which ensures for the internal circuitry to work properly depends on the ambient temperature. If it’s too low and the regular doesn’t have enough supply current left the output appears to be dead.
Which honestly makes very little sense to me, and also reads a bit like a terminology tombola. A quick googling did not turn up more material on the idea that voltage regulators depend on the temperature like that, and it would be surprising (generally electronics performs better when cooled).
I would expect the problem to be due to a bad solder joint, which would explain why heating it helps since it might make the solder flow a little bit back into making connection (although hair dryer temperatures at 200°F/93°C) are too low to properly reflow solder). Or it might just make components and/or solder expand enough to make contact (which is kind of the same thing but different).
In the olden days we used to use hair driers and cans of "freezer spray" - ozone-depleting freon in a can, now replaced with more eco-friendly stuff - to heat and cool components to see which ones were temperature-sensitive. Quite often you'd get a fault that would only show up when the set was cold, or only after it was thoroughly warm.
I'm wondering if perhaps C206/C207/C208 in the LDO circuit that decouple the output might have gone a bit leaky and warming them up causes them to act more like capacitors and less like resistors to ground. If they're SMD multilayer ceramics that would be a pretty common failure.
The part is a LDO (low-dropout regulator). You can read about these here. See also the section about the quiescent current. One more thing: what made you believe that the given explanation is wrong?
It's not uncommon for solder joints to get damaged due to heat stress. It happens to BGA compontents too when not properly cooled. The hair dryer may or may not have provided enough heat to fix a small crack (I didn't look up the temperature a hair dryer provides).
Did kind-of the same with my Philips TV a while back. Still going strong.
I agree, it makes no sense. I am a real hardware electronics engineer and I don't understand his explanation. I believe the LDO could fail in a temperature dependent way. I do not believe the explanation.
I am not an expert, just a hobbyist. It's hard to tell anything without measurements. Either the regulators are half dead (factory spec for operating temperature is -40 to +85 C°) and should be replaced, or thermal expansion causes a cracked solder joint to touch again, or some other component is half dead and needs a bit of warmth to work properly.
>A quick googling did not turn up more material on the idea that voltage regulators depend on the temperature like that, and it would be surprising (generally electronics performs better when cooled).
Not a hardware expert either, but Wikipedia points at this TI doc[0] which claims ambient temperature is necessary for the quiescent current. There's no mechanism described there, though.
This observation isn't directly applicable to this story in particular, as this case the fix did require some in depth troubleshooting knowledge of the subject.
That being said, I'm often struck by how often something can be fixed by just opening it up and looking at it, even if you know next to nothing about the internals.
Two examples, both car-related:
- I used to drive an old Ford Ranger, and one day it started running like crap. Horrible acceleration, engine running rough. I made an appointment with a mechanic, but the day before my appointment I thought "What the heck, I might as well look at it." I popped the hood and immediately noticed that the air filter housing was cracked in half. Patched it up with duct tape, and it was good as "new".
- One of my wheels started making a godawful constant squealing. I couldn't drive 10 yards without turning heads. I brought it into the mechanic, where they took the wheel off and promptly a pebble fell out of the brake calipers. Had I just jacked it up and taken the wheel off myself, I would have saved a trip to the mechanic.
I would never guess that a piece of even consumer hardware was designed with such low tolerances as to develop such issues.
Is this some kind of a trend that I'm not up to date with?
I was surprised to find out that my laptop fans started first getting noisy and then rattling after less than two years since purchase. I searched around and apparently the tight tolerances combined with low quality of the bearings eventually produce this effect.
This is especially audible if I let them heat up - it appears that thermal expansion is enough for the blades to get too close to the housing.
I ordered a set of new ones and appropriate tools, but I can't imagine doing this every two years. My previous laptop lasted around seven, after which both the battery and the power socket gave out.
> Is this some kind of a trend that I'm not up to date with?
It's called planned obsolescence and it's part of the factory-to-landfill pipeline. It's not exactly new.
Do we know how to make a long lasting laptop fan? Yes. Would nearly every consumer pay $0.25 more for a laptop with a longer lasting fan? Yes. Can you buy laptops with high quality fans? Yes, but seemingly only by dumb luck.
By the time you figure out that a product has a high failure part the company will no longer be manufacturing it and therefore reviews won't be relevant (granting relative immunity to bad reviews). And when every brand is doing it, there's no way for "free market" competition to sort it out. It's a race to the bottom. (3. 2. 1. Cue "The morality of protecting share holders eclipses the morality of ripping consumers off.")
I only buy used laptops now. The significant reduction in price is a reduction in risk. Also a used product has had "burn in" time to weed out the lemons. The engineer calculated xx% of fail-early laptops often aren't the ones being resold.
I'm bitter. I'm cynical. Despite being aware of my mind's ability to find patterns to confirm my biases... I'm really struggling to be excited about new products. I'm spent like nuclear fuel; I'm toxic. They say knowing is half the battle... not in psychology. Doesn't help me a damned bit.
Today's sponsor is Better Help. I should just stop now.
He's talking about a 12 years-old screen that probably saw daily use. Something failing at that point is more than expected.
As others have noted, it's in fact probably bad capacitors, which is a really common issue for electronics of that era. I also encountered that several times, it's a quick fix if you know how to solder new ones, and you can find such capacitors for cheap (like 1$ cheap last time I had to look, though finding that price for a single one is hard, and much less when bought in bulk).
>I would never guess that a piece of even consumer hardware was designed with such low tolerances as to develop such issues.
It wasnt, the explanation in the blog is nonsense. 10 years is a good lifespan for capacitors working in hot environment, and that is what failed. Electrolytic Capacitors are perishable, they age even when not used.
>I ordered a set of new ones and appropriate tools, but I can't imagine doing this every two years. My previous laptop lasted around seven, after which both the battery and the power socket gave out.
then use better quality replacement mechanical part. People arent surprised when servicing cars, why different expectations with modern electronics?
If this is the case, you could consider bearingless fans, which should prevent them from wearing out. The only issue is you may not be able to find them in the size requirement you need.
I fixed a 2008 macbook with a GPU issue (wouldn't boot past BIOS) by turning it on and letting it run full-tilt under a blanket. Eventually it just resoldered itself.
It didnt. 8600M had a design defect in microbumps connecting die to package. Thermal cycling in high heat scenarios (Apple is famous fo cooking components at the margin of T-junction) softened improperly selected underfill and broke microbumps connecting die to package. Repeated heating up can again soften it to release stresses and temporarily reconnected broken traces. It never fixes the main issue of broken chip.
>On July 2, 2009, the date being ironically a year after the notorious 8-K that publicly kicked off bumpgate, the company put up a job listing for a “DIRECTOR OF PACKAGE TECHNOLOGY”.
Can confirm that this saved our old Samsung lcd television.
It took longer and longer to turn on. Some guy on YouTube used this hair dryer trick. So I did just that, blow the air inside the TV from below through the panels, and like magic it works again. Life hack!
Sandwich one of those silly cheapo USB mug warmers into the case. Plug it in briefly for a little warmth just to get it going. Like a choke on an old-fashioned car!
Not to be a worry wart, but a long time ago we got a batch of monitors with a defective board. A capacitor overheated, melted some sort of glue on an adjacent component, which in turn dripped on a power supply component, shorted out and started a fire.
A couple of days later, it happened again… and we ended up getting all hands on deck to find those monitors.
Reminds me of the "myth" of putting a Radeon GPU into the oven on low heat for a while if it was broken. I tried it when mine stopped working and indeed it fixed it.
Also another Radeon card was identical as a more powerful one, except that two pins (maybe wrong word) were not connected. I drew the connection using a pencil directly on the board and it worked as well, saving around 100 Euros.
It's over a decade ago, so details may be slightly wrong. But still interesting how low tech solutions worked on such complicated machinery.
I love the last picture with their desk covered in stickers. I thought we were supposed to keep the stickers in a box forever until we find the "perfect" use for them...
Hair dryers can be quite useful. If you have a small engine that won't start like a lawnmower, heating it with a hair dryer will often allow it to crank.
My old Benq monitor was blinking for the fist 10-20 minutes when I turn it on and I used similar trick. I knew nothing about electronics and used common sense. I would direct hair dryer towards air vents of the monitor and wait for 30 seconds.
I got bored after a month repeating the same thing every day and sold it unrepaired.
I wonder if there could be another issue. I remember we had a hardware guy once where I worked who took apart a broken cable modem prototype, found that one of the traces was thinly broken. Traces are the lines on a printed circuit board, Vias the circles. He used an emory cloth to strip the protective green coating, then a small narrow heat gun to melt the trace slightly and bring it together.
If OP had a broken trace in there, then heat might have fixed it. Then again, OP's reasoning is probably better as I am not a hardware guy.
Kinda reminded me of the time I used listerine on my MacBook screen and it solved the gross reflective coating issue that apple wouldn’t fix for me. Crazy part is it worked
[+] [-] femto|3 years ago|reply
There are electrolytic capacitors near where he was heating, and the capacitance of electrolytics can have a strong temperature dependence. He probably managed to heat one of the electrolytic capacitors, which happened to change its capacitance in the correct direction to make the circuit work.
Chances are the monitor would work reliably if all the electrolytic capacitors were replaced.
Edit:
I'm guessing the problem is C208. Section 10 of the LDO data sheet, linked in the article, talks about how stability is dependent on the output capacitor (C208). C208 has probably dried out, reducing its capacitance and making the LDO unstable. Heating was enough to make the circuit stable (for a while).
Further edit:
Predating my comment, "Gordonjcp" also called out C208.
[+] [-] ChrisMarshallNY|3 years ago|reply
In over 35 years of troubleshooting gear and systems, my experience is that 90% (no exaggeration) of problems are bad cables.
It seems even worse, these days, with high-speed serial cables, running on razor-thin margins, and often with embedded ICs.
That's why, when the IT geek comes to your desk, they just rip out all your cables, and replace them with new ones, out of the shrink-wrap. They'll toss out a hundred dollars' worth of perfectly good cables, because they know the deal. They could waste an hour, trying to troubleshoot a problem caused by an intermittent USB C cable.
[+] [-] anonymousiam|3 years ago|reply
Also, here's a related article describing how a Chinese failure at industrial espionage created a worldwide capacitor problem: https://www.theguardian.com/technology/blog/2010/jun/29/dell...
[+] [-] nneonneo|3 years ago|reply
Lo and behold, I saw three 1000uF caps that had leaked, one of which had a clear bulge on the top. So I ordered a bunch of replacements off Mouser, bought myself a soldering iron, and replaced all three. Worked like a charm!
I’ll never understand why even high-end equipment manufacturers wind up using crappy knockoff capacitors in their stuff. It seems like it’s just a failure waiting to happen. I guess they get to make good money on the support and service?
[+] [-] userbinator|3 years ago|reply
[+] [-] whoopdedo|3 years ago|reply
[+] [-] dbrgn|3 years ago|reply
[+] [-] Pixelbrick|3 years ago|reply
[+] [-] pierrebai|3 years ago|reply
[+] [-] mikepurvis|3 years ago|reply
[+] [-] prawn|3 years ago|reply
https://en.wikipedia.org/wiki/Micro_Genius
There's a photo of us smiling at the counter of a department store, handing over money. We bought a couple of multi-game cartridges. 190-in-1 and 27-in-1 or something.
We tested it in a Hong Kong hotel room, and briefly played a few games. Then imagine our dismay when we eventually got back to Australia and the thing wouldn't reliably load a game. We were blowing on cartridges and all that.
One day, we gave it a shot up in our non-A/C, second-storey bedroom. It was a 40 deg C day, so absolutely cooking upstairs. The console worked! The games loaded! We got to play an assorted of games we'd been eagerly waiting on.
We eventually decided it must be the heat and on the next day I can remember us taking it in turns with a hairdryer trying to warm the console or cartridge to get a game to start while the other person played. It might let us play for several minutes and then fail. Unfortunately, this trick didn't last for long and then the console was surpassed and the games no longer kept our interest.
30 years later, I still have the useless boxed console in my garage and can't bear to throw it out.
[+] [-] rocky1138|3 years ago|reply
[+] [-] pvillano|3 years ago|reply
[+] [-] unwind|3 years ago|reply
> A common issue with these types of components is that the quiescent current which ensures for the internal circuitry to work properly depends on the ambient temperature. If it’s too low and the regular doesn’t have enough supply current left the output appears to be dead.
Which honestly makes very little sense to me, and also reads a bit like a terminology tombola. A quick googling did not turn up more material on the idea that voltage regulators depend on the temperature like that, and it would be surprising (generally electronics performs better when cooled).
I would expect the problem to be due to a bad solder joint, which would explain why heating it helps since it might make the solder flow a little bit back into making connection (although hair dryer temperatures at 200°F/93°C) are too low to properly reflow solder). Or it might just make components and/or solder expand enough to make contact (which is kind of the same thing but different).
All real hardware experts, please explain. :)
[+] [-] Gordonjcp|3 years ago|reply
I'm wondering if perhaps C206/C207/C208 in the LDO circuit that decouple the output might have gone a bit leaky and warming them up causes them to act more like capacitors and less like resistors to ground. If they're SMD multilayer ceramics that would be a pretty common failure.
[+] [-] _Microft|3 years ago|reply
https://en.wikipedia.org/wiki/Low-dropout_regulator
https://en.wikipedia.org/wiki/Low-dropout_regulator#Quiescen...
[+] [-] ariejan|3 years ago|reply
Did kind-of the same with my Philips TV a while back. Still going strong.
https://www.devroom.io/projects/repair-philips-42pfl6057h-12...
[+] [-] pie314isi|3 years ago|reply
[+] [-] jonsen|3 years ago|reply
Or inside the IC a bad bonding between the chip and the package leads. Or IC package developed cracks and moisture creeps in.
[+] [-] type0|3 years ago|reply
Yeah, most probably it deformed into contact
[+] [-] laci37|3 years ago|reply
[+] [-] ivanbakel|3 years ago|reply
Not a hardware expert either, but Wikipedia points at this TI doc[0] which claims ambient temperature is necessary for the quiescent current. There's no mechanism described there, though.
[0]: https://www.ti.com/lit/an/slva079/slva079.pdf
[+] [-] audiometry|3 years ago|reply
[+] [-] justusthane|3 years ago|reply
That being said, I'm often struck by how often something can be fixed by just opening it up and looking at it, even if you know next to nothing about the internals.
Two examples, both car-related:
- I used to drive an old Ford Ranger, and one day it started running like crap. Horrible acceleration, engine running rough. I made an appointment with a mechanic, but the day before my appointment I thought "What the heck, I might as well look at it." I popped the hood and immediately noticed that the air filter housing was cracked in half. Patched it up with duct tape, and it was good as "new".
- One of my wheels started making a godawful constant squealing. I couldn't drive 10 yards without turning heads. I brought it into the mechanic, where they took the wheel off and promptly a pebble fell out of the brake calipers. Had I just jacked it up and taken the wheel off myself, I would have saved a trip to the mechanic.
[+] [-] Tade0|3 years ago|reply
Is this some kind of a trend that I'm not up to date with?
I was surprised to find out that my laptop fans started first getting noisy and then rattling after less than two years since purchase. I searched around and apparently the tight tolerances combined with low quality of the bearings eventually produce this effect.
This is especially audible if I let them heat up - it appears that thermal expansion is enough for the blades to get too close to the housing.
I ordered a set of new ones and appropriate tools, but I can't imagine doing this every two years. My previous laptop lasted around seven, after which both the battery and the power socket gave out.
[+] [-] li2uR3ce|3 years ago|reply
It's called planned obsolescence and it's part of the factory-to-landfill pipeline. It's not exactly new.
Do we know how to make a long lasting laptop fan? Yes. Would nearly every consumer pay $0.25 more for a laptop with a longer lasting fan? Yes. Can you buy laptops with high quality fans? Yes, but seemingly only by dumb luck.
By the time you figure out that a product has a high failure part the company will no longer be manufacturing it and therefore reviews won't be relevant (granting relative immunity to bad reviews). And when every brand is doing it, there's no way for "free market" competition to sort it out. It's a race to the bottom. (3. 2. 1. Cue "The morality of protecting share holders eclipses the morality of ripping consumers off.")
I only buy used laptops now. The significant reduction in price is a reduction in risk. Also a used product has had "burn in" time to weed out the lemons. The engineer calculated xx% of fail-early laptops often aren't the ones being resold.
I'm bitter. I'm cynical. Despite being aware of my mind's ability to find patterns to confirm my biases... I'm really struggling to be excited about new products. I'm spent like nuclear fuel; I'm toxic. They say knowing is half the battle... not in psychology. Doesn't help me a damned bit.
Today's sponsor is Better Help. I should just stop now.
[+] [-] slig|3 years ago|reply
[+] [-] Fradow|3 years ago|reply
As others have noted, it's in fact probably bad capacitors, which is a really common issue for electronics of that era. I also encountered that several times, it's a quick fix if you know how to solder new ones, and you can find such capacitors for cheap (like 1$ cheap last time I had to look, though finding that price for a single one is hard, and much less when bought in bulk).
[+] [-] rasz|3 years ago|reply
It wasnt, the explanation in the blog is nonsense. 10 years is a good lifespan for capacitors working in hot environment, and that is what failed. Electrolytic Capacitors are perishable, they age even when not used.
>I ordered a set of new ones and appropriate tools, but I can't imagine doing this every two years. My previous laptop lasted around seven, after which both the battery and the power socket gave out.
then use better quality replacement mechanical part. People arent surprised when servicing cars, why different expectations with modern electronics?
[+] [-] ungamedplayer|3 years ago|reply
Good luck !
[+] [-] rompic|3 years ago|reply
There are a lot of similar 10 year old reports on the net. E.g.: https://www.badcaps.net/forum/showthread.php?t=24494&highlig...
[+] [-] abofh|3 years ago|reply
1$ - Blowing a hairdryer at the monitor
9,999$ - Knowing where to point the hair dryer...
[+] [-] mdrzn|3 years ago|reply
I would have no idea where to start to find that fix, or even where to find the schematics!
[+] [-] mmastrac|3 years ago|reply
[+] [-] rasz|3 years ago|reply
https://en-academic.com/dic.nsf/enwiki/2011837#Problems
https://semiaccurate.com/2009/08/21/nvidia-finally-understan...
>On July 2, 2009, the date being ironically a year after the notorious 8-K that publicly kicked off bumpgate, the company put up a job listing for a “DIRECTOR OF PACKAGE TECHNOLOGY”.
https://notebooks.com/2008/10/10/apple-to-replace-faulty-nvi...
[+] [-] gijsnijholt1980|3 years ago|reply
It took longer and longer to turn on. Some guy on YouTube used this hair dryer trick. So I did just that, blow the air inside the TV from below through the panels, and like magic it works again. Life hack!
Curious why it works though
[+] [-] adav|3 years ago|reply
[+] [-] Spooky23|3 years ago|reply
Not to be a worry wart, but a long time ago we got a batch of monitors with a defective board. A capacitor overheated, melted some sort of glue on an adjacent component, which in turn dripped on a power supply component, shorted out and started a fire.
A couple of days later, it happened again… and we ended up getting all hands on deck to find those monitors.
[+] [-] tomxor|3 years ago|reply
Also good to think of alternative fixes like this when it's difficult to source replacement components.
[+] [-] Knufferlbert|3 years ago|reply
Also another Radeon card was identical as a more powerful one, except that two pins (maybe wrong word) were not connected. I drew the connection using a pencil directly on the board and it worked as well, saving around 100 Euros.
It's over a decade ago, so details may be slightly wrong. But still interesting how low tech solutions worked on such complicated machinery.
[+] [-] barbazoo|3 years ago|reply
[+] [-] causality0|3 years ago|reply
[+] [-] jwilk|3 years ago|reply
https://archive.today/eAmar
[+] [-] f311a|3 years ago|reply
I got bored after a month repeating the same thing every day and sold it unrepaired.
[+] [-] 1970-01-01|3 years ago|reply
https://badcaps.net/forum/showpost.php?p=1002389&postcount=7
[+] [-] favadi|3 years ago|reply
[+] [-] bryanrasmussen|3 years ago|reply
[+] [-] mrexroad|3 years ago|reply
[+] [-] Communitivity|3 years ago|reply
If OP had a broken trace in there, then heat might have fixed it. Then again, OP's reasoning is probably better as I am not a hardware guy.
[+] [-] r0m4n0|3 years ago|reply
Context: https://www.reddit.com/r/mildlyinteresting/comments/gho3s4/m...