A VGA monitor may be easier to repair than you think(cnx-software.com)
cnx-software.com
A VGA monitor may be easier to repair than you think
https://www.cnx-software.com/2021/09/06/how-to-repair-vga-monitor-flatron-w1934s/
127 comments
Low ESR only matters for PWM filtering capacitors, such as those found in monitor backlight drivers and some switching power supplies’ secondary circuits.
It is not necessary to use such capacitors on the primary side, i.e. when the large capacitor nearest to the mains input dies, just replace it with a normal electrolytic capacitor that matches or exceeds the original’s voltage rating and closely matches its capacity.
It is not necessary to use such capacitors on the primary side, i.e. when the large capacitor nearest to the mains input dies, just replace it with a normal electrolytic capacitor that matches or exceeds the original’s voltage rating and closely matches its capacity.
Worse yet, sometimes the circuit won't work with a low-ESR capacitor. For example, you can't put a low-ESR capacitor on the output of an LM1117, it will oscillate.
In a pinch, that could be compensated with a resistor, a few ohms would suffice… :)
Aye I remember bringing back a lot of dead monitors, TV's and even a cheap Pentium 4 motherboard by swapping caps.
A place I worked at had a bunch of 19" Optiquest LCD monitors which ALL eventually died from a single bad cap on the power supply board. I fixed every one of those monitors, think it cost less than $10 to order the caps from digikey.
A place I worked at had a bunch of 19" Optiquest LCD monitors which ALL eventually died from a single bad cap on the power supply board. I fixed every one of those monitors, think it cost less than $10 to order the caps from digikey.
How do you figure out which ones are bad?
Some can be easily spotted by visual inspection for being bulged just like the one in the linked article photo, others will need to be measured.
Leakage (ie, when a capacitor exhibits resistive properties by conducting current also when fully charged) can be measured easily by using an analog tester or a digital one plus a few parts, while the ESR (equivalent series resistance) measurement would need a proper instrument called ESR meter. The ESR is an unwanted static series resistance the capacitor would exhibit no matter the frequency it works at, it increases with aging and it's independent from the capacitive reactance which it's related to the frequency. Therefore, the lower the ESR, the better quality or condition is the capacitor.
However, you can just ignore the 2nd sentence if repairing a device would require just a bunch of capacitors; quality ones aren't that pricey, and if you find a bulged one, it is often advised to replace all capacitors employed in the same stage anyway. Some in fact can degrade without showing any visible hints of their condition.
Leakage (ie, when a capacitor exhibits resistive properties by conducting current also when fully charged) can be measured easily by using an analog tester or a digital one plus a few parts, while the ESR (equivalent series resistance) measurement would need a proper instrument called ESR meter. The ESR is an unwanted static series resistance the capacitor would exhibit no matter the frequency it works at, it increases with aging and it's independent from the capacitive reactance which it's related to the frequency. Therefore, the lower the ESR, the better quality or condition is the capacitor.
However, you can just ignore the 2nd sentence if repairing a device would require just a bunch of capacitors; quality ones aren't that pricey, and if you find a bulged one, it is often advised to replace all capacitors employed in the same stage anyway. Some in fact can degrade without showing any visible hints of their condition.
[deleted]
> the market is literally invaded by rubbish quality capacitors, and swapping a bad quality one with another bad quality one guarantees it will fail again one day
Actually, even a quality capacitor will fail eventually, just not as early as the fake ones. As you have mentioned about the heat, the capacitor will be exposed to it and will fail because of it.
Actually, even a quality capacitor will fail eventually, just not as early as the fake ones. As you have mentioned about the heat, the capacitor will be exposed to it and will fail because of it.
I have replaced more capacitors in appliances than electronics. The fact that appliances runs on higher voltages and stop/starts frequently exacerbate the heat problem.
The 9 years old range hood in my kitchen is already had the start capacitor replaced twice. Whoever designed this unit decided to place the circuitry right in a hot spot, making sure that the capacitor will be gently toasted to death in a couple of years.
The 9 years old range hood in my kitchen is already had the start capacitor replaced twice. Whoever designed this unit decided to place the circuitry right in a hot spot, making sure that the capacitor will be gently toasted to death in a couple of years.
Planned obsolescence using wrongly placed capacitors is one of the few conspiracy theories I tend to believe in (I guess it is conspiracy). I also successfully repaired an old telefone system, a washing machine and an old TV 15 years ago because the same capacitors failed so frequently that even without any knowledge one would be able to Google what needed to be exchanged together with order links. However, I think manufacturers really found better strategies for planned obsolescence eg. by introducing new communication standards or turning off server and not providing software updates. So during the last 10 years I mostly threw away fully functional hardware...
good caps go bad, too. service lifetime is a function of temperature and time. lower the operating temp by 10°C and you double the lifespan of the good name-brand capacitor, and probably quadruple the life of the crappy generic cap.
Then again, if the item you are repairing is 4 years old or more, then the original caps have enough life span to justify using same quality replacements. Sure, you might only be saving 30 cents on an individual item (not counting shipping), but if its what you have on hand there's not really a downside.
Huh. I have a Dell monitor that suddenly started showing these kind of smeared stripes instead of a proper picture. Took it apart, looked carefully at all the capacitors and other components on both boards, but none looked bad. Disconnecting and reconnecting the ribbon that goes to the LCD panel made no difference whatsoever. What could it possibly be?
Interestingly I have 5 Dell monitors, and 10 Samsungs that are 15 years old. Dells are all still running strong. While the Samsungs have needed replacement Caps, and their DVI ports have flaked out. I did find that if I use the VGA port they will work well though, strange...
If there are vertical lines most likely Cof or T-Con board failure. Unfortunately it isn't an easy repair. (Although some YouTube videos show you can work around some minor cof failures by isolating broken lines with a tape)
does a bad capacitor always show damage visibly?
Most likely it will simply NOT power on. That or briefly power on and shut off once the ripple spikes and glitches everything.
In another post here I mentioned fixing Optiquest monitors. The usual issue was you would press the power button and the power LED would flah for a second and... nothing. This is because the output cap of the switching supply would cease to filter the high speed square wave that goes through the transformer. So your DC power supply is now an AC square wave supply. Of course logic circuits don't like that so they will outright fail.
Sometimes there is enough capacitance via decoupling caps, ground planes on the PCB and local filter caps on the logic board so the initial power up works but once the load increases the ripple increases until it becomes AC again and everything goes haywire or shuts down.
In another post here I mentioned fixing Optiquest monitors. The usual issue was you would press the power button and the power LED would flah for a second and... nothing. This is because the output cap of the switching supply would cease to filter the high speed square wave that goes through the transformer. So your DC power supply is now an AC square wave supply. Of course logic circuits don't like that so they will outright fail.
Sometimes there is enough capacitance via decoupling caps, ground planes on the PCB and local filter caps on the logic board so the initial power up works but once the load increases the ripple increases until it becomes AC again and everything goes haywire or shuts down.
no. but often does.
Capacitors can be bad but look perfectly fine.
If there aren't many, one can just replace all of them.
If there aren't many, one can just replace all of them.
Since the title specified a resolution, I assumed a VGA CRT with a DB15 connector. (Not an MDA, CGA or EGA) I was all set to warn you kids about the dangers of CRTs, high voltage, Xrays, and of course the implosion if you break the neck of the tube... and instead got bad capacitors on LCD displays.
Regardless of what the safety standards say, you should always remove power, and short any capacitors with a screwdriver or freshly checked jumper lead, as bleeder resistors (and jumper leads) fail. LCD backlights with cold cathode fluorescents use quite a bit of voltage, so be careful, and good luck!
Regardless of what the safety standards say, you should always remove power, and short any capacitors with a screwdriver or freshly checked jumper lead, as bleeder resistors (and jumper leads) fail. LCD backlights with cold cathode fluorescents use quite a bit of voltage, so be careful, and good luck!
I also immediately had flash-backs to opening up an old CRT 13" TV that was going flaky (the sort of flaky where sometimes percussive maintenance worked). Being an electrical engineering student at the time, I thought I could handle it. I knew about the high voltage, I knew about the retained charged of the capacitors, etc, etc. What I wasn't prepared for was just how poorly shielded this thing was once I got it opened.
I shocked myself almost immediately as I was doing basic examination. I hadn't even gotten to probing for shorts or broken connections. Thankfully, the shock wasn't bad, more startling than anything (I remember it being somewhat like brushing up against an electric fence). I was wearing a grounding strap on the arm of the hand where I got shocked. Not sure how much/if that helped any.
That was enough for me to determine I wasn't qualified to work on it. I reattached the case and lived with its flakiness for a few years longer until it was replaced with an LCD.
I shocked myself almost immediately as I was doing basic examination. I hadn't even gotten to probing for shorts or broken connections. Thankfully, the shock wasn't bad, more startling than anything (I remember it being somewhat like brushing up against an electric fence). I was wearing a grounding strap on the arm of the hand where I got shocked. Not sure how much/if that helped any.
That was enough for me to determine I wasn't qualified to work on it. I reattached the case and lived with its flakiness for a few years longer until it was replaced with an LCD.
> short any capacitors with a screwdriver
Not universally a good idea to do that, especially not in a power supply. Safe enough in some circumstances but not all. Better to buy a discharge probe or make one by soldering a 2200 ohm 5w resistor between a couple of insulated wires.
EDIT: made it less condescending.
Not universally a good idea to do that, especially not in a power supply. Safe enough in some circumstances but not all. Better to buy a discharge probe or make one by soldering a 2200 ohm 5w resistor between a couple of insulated wires.
EDIT: made it less condescending.
Things can fail open, a screwdriver can't. What's wrong with putting a dead short once across a capacitor? I've been doing it for 40 years in the interest of safety. Usually the bleeders are done and nothing happens anyway.
Nothing, as long as it's a low voltage capacitor. Do it to a filter cap in a power supply and you'll have a huge spark and probably damage your screwdriver. Best practice if you're working with large capacitors is to discharge it (safely, using the tool I described), and confirm it worked using a voltmeter.
I learned dealing with 600V monster filter capacitors in vacuum tube power supplies, they'll happily vaporize a screwdriver and knock you off your feet in the process.
I learned dealing with 600V monster filter capacitors in vacuum tube power supplies, they'll happily vaporize a screwdriver and knock you off your feet in the process.
Thanks. I appreciate when someone gives safety advices as they come in handy when starting to tinker electronics. When repairing dishwasher I had to disconnect a huge capacitor... well it looked like it. Knowing what you just wrote about capacitors, it gave me shrugs and I was VERY careful handling that piece of thing.
Can you give any advice on what good fume extractor for soldering does and if hobbyist that does repairs now and then should care?
Can you give any advice on what good fume extractor for soldering does and if hobbyist that does repairs now and then should care?
Solder fumes aren't great for your lungs, but its not a severe health threat: you're not soldering that much. A fan blowing at you to keep smoke and fumes out of your face should be sufficient for up to a few hours a day of soldering. If others in the house complain about the smell, then work on venting outside harder.
A fume extractor with an activated charcoal filter grabs up the organic solvents that were used as flux to help make a good solder connection, and keep them out of your lungs. They don't cost much, but if smoke goes in, and doesn't come out, its helping, even if it isn't perfect.
I did this kind of a repair job to a couple of Samsung 23" 1080p screens back in 2012.
A friend gave them away since their backlights would flicker making the monitor unusable for the first 10 or so minutes after they were turned on, after which they worked completely fine.
I have little to no knowledge of electronics, but did know how to use a soldering iron. As I recall, I watched a YouTube video and was confident that if the problem was just the capacitors, then I could manage to replace them.
I opened up the monitor, saw two or three capacitors which were clearly bulging and I used a soldering iron to get them off the board.
I went to an electronics shop expecting that someone there would be able to advise on replacements which would work. As I recall one or more of replacements they had available on hand had a different "number" on it, but they assured me it was a higher rating and wouldn't affect use, I don't know much about electronics, but this made sense to me so I trusted it.
I managed to re-solder them on and they then worked perfectly.
Fast forward to today, about 9 years later, and my brother is still using both the repaired monitors. They have DVI input, 1080p resolution and VESA mounts so are actually very decent unless things like >60Hz refresh rate, higher resolution or very good colour accuracy are important to you.
A friend gave them away since their backlights would flicker making the monitor unusable for the first 10 or so minutes after they were turned on, after which they worked completely fine.
I have little to no knowledge of electronics, but did know how to use a soldering iron. As I recall, I watched a YouTube video and was confident that if the problem was just the capacitors, then I could manage to replace them.
I opened up the monitor, saw two or three capacitors which were clearly bulging and I used a soldering iron to get them off the board.
I went to an electronics shop expecting that someone there would be able to advise on replacements which would work. As I recall one or more of replacements they had available on hand had a different "number" on it, but they assured me it was a higher rating and wouldn't affect use, I don't know much about electronics, but this made sense to me so I trusted it.
I managed to re-solder them on and they then worked perfectly.
Fast forward to today, about 9 years later, and my brother is still using both the repaired monitors. They have DVI input, 1080p resolution and VESA mounts so are actually very decent unless things like >60Hz refresh rate, higher resolution or very good colour accuracy are important to you.
>they had available on hand had a different "number" on it, but they assured me it was a higher rating and wouldn't affect use
It's probably the amount of farad units the capacitor is rated for. You can often use a capacitor with higher farads as long as the voltage is the same and it can be even more reliable than the original part, the only trouble is sometimes they are physically larger or taller, so you have to be careful if you're working in tight spaces.
It's probably the amount of farad units the capacitor is rated for. You can often use a capacitor with higher farads as long as the voltage is the same and it can be even more reliable than the original part, the only trouble is sometimes they are physically larger or taller, so you have to be careful if you're working in tight spaces.
Seems more likely that it would be the voltage rating? While it’s true that a larger capacitance would be fine in many applications, it wouldn’t always be (e.g. if the cap is part of an RC filter or if it’s used as a bypass cap). In contrast the voltage rating of a cap is just a maximum.
I think you are right, I might've got it mixed up!
I feel old; I came here for a guide to repair a "VGA monitor" and instead got a flat panel.
I am old. I did not even open the link until you mentioned it was an LCD. I was thinking: "Why would you repair a CRT?"
Comes up fairly often as a nostalgia thing for old Macs, Kaypros, Compaqs, arcade games, and so on.
Also, some home computer games from the 80s can be really hard to play with any extra latency so a CRT helps.
For most of the last 15 years, if you had an old CRT television or computer monitor, you had actually to pay someone just to get rid of it. Because of the lead shielding used in CRT tubes, they are considered hazardous waste. (Of course, most people were irresponsible or just didn't know any better and just chucked theirs into a dumpster.)
But in the past few years, retro tech has become sufficiently popular due to certain YouTube channels that a CRT TV or monitor in good working condition can now command a worthwhile price.
But in the past few years, retro tech has become sufficiently popular due to certain YouTube channels that a CRT TV or monitor in good working condition can now command a worthwhile price.
> I was thinking: "Why would you repair a CRT?"
Same here. And I didn't think I was that old...
Same here. And I didn't think I was that old...
Lots of older equipment require a CRT to function properly.
Or maybe if you want to play arcade games ;)
LCD monitors only used VGA because customers didn't know enough to demand DVI. A pixel array is inherently digital, so it makes no sense to put DAC/ADC in the path.
> customers didn't know enough to demand DVI
Really, it was more that we didn't have DVI outputs.
Its the smartest way to break the chicken-egg situation -- for many (I'd wager the majority) the advantage of a flat panel at first was more about space saving then picture quality.
Really, it was more that we didn't have DVI outputs.
Its the smartest way to break the chicken-egg situation -- for many (I'd wager the majority) the advantage of a flat panel at first was more about space saving then picture quality.
DVI output was easy; just buy a video card.
The problem is, you can't add DVI to a VGA-only LCD monitor, and those things were everywhere.
The problem is, you can't add DVI to a VGA-only LCD monitor, and those things were everywhere.
I'm always wary if these guides. If you know what you're doing then yes, replacing a capacitor is a quick fix to give your hardware a new lease on life, but you can get seriously injured or even killed if you mishandled the open power supplies these devices often contain.
This guide addresses the danger by saying you need to "wait for a while" without telling you what "a while" is (a minute? 5? an hour?) and how to spot the dangerous parts of the circuit board.
Having said all that, I think a general education on how devices like these can be fixed (safely!) is something a lot educational facilities should offer. Repairing basic and often even more advanced electronics requires little more than replacement parts, a soldering iron and some practice, but people are quick to throw something out when it stops working. The assumption seems to be that things are too complex to repair these days, but in all likelihood dead devices just had some protective circuitry do its job and fail before frying the mail circuits.
This guide addresses the danger by saying you need to "wait for a while" without telling you what "a while" is (a minute? 5? an hour?) and how to spot the dangerous parts of the circuit board.
Having said all that, I think a general education on how devices like these can be fixed (safely!) is something a lot educational facilities should offer. Repairing basic and often even more advanced electronics requires little more than replacement parts, a soldering iron and some practice, but people are quick to throw something out when it stops working. The assumption seems to be that things are too complex to repair these days, but in all likelihood dead devices just had some protective circuitry do its job and fail before frying the mail circuits.
IEC 60335 and IEC 62368 state that the voltage across the capacitors must be below 34 V in 1 second after the input power is removed. Modern electronics are remarkably safe and I have never heard of anyone being shocked by power supply capacitors in the last decade. Of course cheap electronics sometimes aren't standards compliant and bleed resistors can conceivably fail hence the advice to wait a bit longer if you want real piece of mind and don't mind waiting.
I had a friend in high school who found it funny to hand unsuspecting people a fully charged capacitor he pulled from a camera flash. This was 30 years ago, before "modern electronics", so the charge lasted longer than a few seconds. Why this never started a fight I don't know.
> before "modern electronics", so the charge lasted longer than a few seconds.
If you take any capacitor and charge it, it'll take quite some time to discharge on its own.
The discharge is usually controlled by a resistor in parallel with the capacitor on the PCB. Removing the capacitor from the board disconnects it from the discharge resistor. So not much "modern electronics" going on here :-P
If you take any capacitor and charge it, it'll take quite some time to discharge on its own.
The discharge is usually controlled by a resistor in parallel with the capacitor on the PCB. Removing the capacitor from the board disconnects it from the discharge resistor. So not much "modern electronics" going on here :-P
I'm working on a project where I may need to open and repair an old device that probably contains some high-voltage capacitors. Would it be relatively safe to do this if I was wearing rubber gloves + shoes, and used a multimeter to check for voltages, and a large resistor to discharge any capacitors? What kind of bleed resistor is typically used, e.g. for old TVs?
This might be a nice feature of a multimeter: discharge mode.
Putting the leads over a capacitor, the multimeter will show the voltage and discharges the capacitor with a constant safe current. Beeps can be used to indicate when the capacitor is safe to handle or not.
Putting the leads over a capacitor, the multimeter will show the voltage and discharges the capacitor with a constant safe current. Beeps can be used to indicate when the capacitor is safe to handle or not.
> a multimeter to check for voltages, and a large resistor to discharge any capacitors
That's all that I use. Don't hold the resistor in your hand though, depending on the size of the capacitor they can get quite hot. I usually use some pliers to hold the resistor.
That's all that I use. Don't hold the resistor in your hand though, depending on the size of the capacitor they can get quite hot. I usually use some pliers to hold the resistor.
If it's 250V or less then that's probably overkill. Rubber gloves alone will protect against a few hundred volts. Bleed resistors depend on the capacitor size but are usually in the high kilaohms.
Just short the positive side to ground to discharge them.
Note: do NOT do this with thin wires and large capacitors / arrays of capacitors, or you may get a hot copper shower.
Note: do NOT do this with thin wires and large capacitors / arrays of capacitors, or you may get a hot copper shower.
Preferably connect it to ground through a resistor.
Computer was unplugged:
"Shawnee teenager is electrocuted while working on a computer":
https://www.kctv5.com/story/19767067/teen-electrocuted-while...
Same story as above as link not available:
https://www.dailymail.co.uk/news/article-2215200/Teenager-Sh...
And a warning:
"I just received an electric shock from an unplugged computer"
https://www.reddit.com/r/computers/comments/53cio2/i_just_re...
"Shawnee teenager is electrocuted while working on a computer":
https://www.kctv5.com/story/19767067/teen-electrocuted-while...
Same story as above as link not available:
https://www.dailymail.co.uk/news/article-2215200/Teenager-Sh...
And a warning:
"I just received an electric shock from an unplugged computer"
https://www.reddit.com/r/computers/comments/53cio2/i_just_re...
What do bleed resistors drain towards if the ground wire has been unplugged by unplugging the monitor?
A charged capacitor has a surplus of electrons on one side, and a shortage on the other. A bleed resistor allows current to flow from one side to the other, balancing the charges on both sides so there is no relative voltage. Q=CV
Great explanation, very helpful! Thank you!
Thank you! I understand this now.
You should never discharge towards the ground wire. The resistor is simply across the two poles of the capacitor.
It's just a resistor over the capacitor that slowly draws current from it. Little enough that it doesn't matter in normal operation, but enough to reasonably quickly discharge the capacitor to a safe level when power is removed.
They don't bleed to ground. Even if the power-chord is disconnected, there still is a circuit between the resistor and the capacitor, and this is where the current runs.
[deleted]
How does this work in practice... do compliant capacitors have to be designed to 'leak' stored charge across an internal resistor or something like that?
[edit] Ah I see this is called a bleed resistor, never mind
[edit] Ah I see this is called a bleed resistor, never mind
They usually just have a normal resistor in parallel with the capacitor. In my experience it's also kind of nice to have minimal load at the output, which makes it a bit easier for the voltage controller.
https://en.wikipedia.org/wiki/Bleeder_resistor
https://en.wikipedia.org/wiki/Bleeder_resistor
Probably this is only about exposed terminals? Like touching the power plug will not shock you, but poking at the internals could.
IEC states what should happen. I strongly suggest making sure that the capacitors are discharged before working on any circuit.
Well, knowing capacitors to be a common culprit with broken monitors might inspire the non-electronics-savvy to go to a repair shop instead of shopping for a new monitor. And save money and the environment I might add.
I think more than a few of us are familiar with the mess of bad capacitors that made their way into products throughout the early 00s. I still see this from time to time, but I remember the first time I encountered it -- I had purchased a $200 SageTV Media Streamer (v1) and it failed a few months out of warranty. I replaced it with a v2 and put the v1 in the basement.
Then Google bought SageTV[0] and they stopped producing software/products. Meanwhile, I wanted another TV hooked up. Taking apart the device revealed capacitors that -- even though I had been unfamiliar with the issues -- were obviously bad -- one had leaked all over itself, others were bulging.
I hit up ebay, repaired that, and thought about the growing pile of unreliable/broken hardware in a room that I had been putting off salvaging. That weekend, I repaired about ten LCD monitors -- caps in the PSU all around, one old plasma TV, 5 ATX power supplies and two NetGear 1Gbps switches. EVERY single one had varying degrees of damage. All but one power supply was functional again.
[0] The product was a TiVo for PCs and was among the best. Google purchased them as an acqui-hire and -- I think -- used portions of the software in their STBs for Fiber. They later released the code open source.
Then Google bought SageTV[0] and they stopped producing software/products. Meanwhile, I wanted another TV hooked up. Taking apart the device revealed capacitors that -- even though I had been unfamiliar with the issues -- were obviously bad -- one had leaked all over itself, others were bulging.
I hit up ebay, repaired that, and thought about the growing pile of unreliable/broken hardware in a room that I had been putting off salvaging. That weekend, I repaired about ten LCD monitors -- caps in the PSU all around, one old plasma TV, 5 ATX power supplies and two NetGear 1Gbps switches. EVERY single one had varying degrees of damage. All but one power supply was functional again.
[0] The product was a TiVo for PCs and was among the best. Google purchased them as an acqui-hire and -- I think -- used portions of the software in their STBs for Fiber. They later released the code open source.
> Then Google bought SageTV[0] and they stopped producing software/products.
Man I remember when that happened. I was happy for the SageTV devs but I knew that was the end of a great run. SageTV was our DVR for years... It was such a cool product!
Man I remember when that happened. I was happy for the SageTV devs but I knew that was the end of a great run. SageTV was our DVR for years... It was such a cool product!
Tangentially related: many VGA monitors can be given a new life by driving their panel using cheap ready made controllers. Search for "hdmi controller board" on Ebay, Aliexpress etc. Some are programmed in advance and the seller must be given the exact name of the panel they will work with before purchasing, while others are sold ready to be programmed. Some can also drive large TV screens.
Here are some links that might turn out useful.
http://www.elecrealm.com/down/class/
http://www.mattmillman.com/info/lcd/rovatools/
https://github.com/ghent360/RTD-2660-Programmer/
https://sites.google.com/site/lcd4hobby/home
http://openrtd2662.ru/
https://www.codeforge.com/article/258602
https://www.panelook.com/index.php
http://lcdtech.info/en/
Here are some links that might turn out useful.
http://www.elecrealm.com/down/class/
http://www.mattmillman.com/info/lcd/rovatools/
https://github.com/ghent360/RTD-2660-Programmer/
https://sites.google.com/site/lcd4hobby/home
http://openrtd2662.ru/
https://www.codeforge.com/article/258602
https://www.panelook.com/index.php
http://lcdtech.info/en/
FTA:
> it was clear what the problem was with a swollen C812 capacitor.
> So no need to check anything with a multimeter or an oscilloscope, a visual inspection of the board could immediately detect the issue.
I'm looking at the picture. I'm not in electronics and I can assure you it's absolutely not clear to me that this is the capacitor I'm looking for. So what should it look like ? I understand these things sometimes burn or swell but is it always visible ? And if not, what should I do to detect it ?
> it was clear what the problem was with a swollen C812 capacitor.
> So no need to check anything with a multimeter or an oscilloscope, a visual inspection of the board could immediately detect the issue.
I'm looking at the picture. I'm not in electronics and I can assure you it's absolutely not clear to me that this is the capacitor I'm looking for. So what should it look like ? I understand these things sometimes burn or swell but is it always visible ? And if not, what should I do to detect it ?
As I understand it, as someone who is also not in electronics, the cross at the top of the other capacitors you can see is designed as a pressure release, it’s a deliberate weakness in the structure of the capacitor so that if it fails, that’s where it will burst. So it’s very likely that if a cap fails, that’s where any swelling will be visible. You can see the cross is distorted/swollen on the failed cap.
I'm an electronic engineer by education and have worked with boards many times as a hobby only though (outside of the university) and I can tell you I do see the capacitor being swollen just from the picture, you can see the ones below are in a normal state. Many times this is very very obvious but other times not in which case you need to remove each capacitor and measure its capacitance with the relevant (cheap) equipment
Sounds like trolling (it's not), but some electrolytic capacitors have a fishy smell when they've leaked.
I did this when I was a teenager - with CRT monitors. Higher voltages and I had the fun of refocusing the tube and fixing the colour registration while it was on, reaching around the back while I looked at my test pattern.
I learnt a lot about computing hardware and software on that Pentium box: 166 MMX (overclocked to 200MHz), 16MB RAM (later 64MB), running Debian and my resurrected 15” LG CRT. Oh, and a 56kbps modem.
I learnt a lot about computing hardware and software on that Pentium box: 166 MMX (overclocked to 200MHz), 16MB RAM (later 64MB), running Debian and my resurrected 15” LG CRT. Oh, and a 56kbps modem.
[deleted]
Power supply caps fail so often that maybe they should be socketed?
Whoever uses junk capacitors to save some cents would never ever spend more money to add a socket. That is not the problem, shitty parts are.
Good capacitors do exist, but they're getting less common with time; actually you're more likely to find good electrolytic caps in a 30 years old radio than in a 5 years old one. Today some manufacturers are cutting corners everywhere and parts quality tanked.
Good capacitors do exist, but they're getting less common with time; actually you're more likely to find good electrolytic caps in a 30 years old radio than in a 5 years old one. Today some manufacturers are cutting corners everywhere and parts quality tanked.
The answer isn't socketed but high quality capacitor ( Solid or Tantalum etc ) . Swollen capacitor should really be a thing of the past.
Unfortunately Capacitor is an area that is easiest to cut cost and has no immediate effect on the devices function and are hard to spot. Part of the reason why I switch over to Mac ~20 years ago. I dont want to spend time looking at every capacitor on a motherboard or to gather enough information on all these details. That was before the time when Capacitor marketing on motherboard was a thing.
Unfortunately Capacitor is an area that is easiest to cut cost and has no immediate effect on the devices function and are hard to spot. Part of the reason why I switch over to Mac ~20 years ago. I dont want to spend time looking at every capacitor on a motherboard or to gather enough information on all these details. That was before the time when Capacitor marketing on motherboard was a thing.
> Capacitor marketing on motherboard was a thing.
That is a thing? What do they advocate, the fine smell of rotten eggs when they die?
That is a thing? What do they advocate, the fine smell of rotten eggs when they die?
It was a long long time ago, before Solid Capacitor were affordable enough to be used in mainstream electronics. Now they are expected in any quality motherboard. At the time they used to market brands like RubyCon for exceptional stability or another brand which I cant remember for similar marketing reason. And redundant capacitor etc.
Last mobo I bought proudly talked about their "Military Grade Capacitors" which is funny because if you know anything about Military Grade that means "whoever will provide a product that meets minimum spec for the least amount of money"
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Why would they be? Less money for the manufacturer.
Just throw the whole thing away (preferably in the garden waste bin for that extra good feeling) and buy a new one. /s
Just throw the whole thing away (preferably in the garden waste bin for that extra good feeling) and buy a new one. /s
Nah soldering isnt that hard an operation and sockets are expensive.
Though it'd be nice if they made those kinds of things more easily accessible, rather than hiding it behind tons of warranty stickers and really tiny screws.
Sure, just saying that it not being socketed should not be that big a barrier to entry. If you want an awesome way of doing things look at old tektronix scopes https://w140.com/tekwiki/wiki/Ceramic_Strips
I'm assuming that the reason why there's so much discussion about soldering techniques and practice on that page is that the tubes failed on a predicable schedule and user servicing the machine was a mandatory part of ownership, right?
The tubes are socketed. Not sure if the soldering was entirely meant for the users or for specialized maintainers, might have been a mix. these things cost the price of a new car and came with similar responsibilities. The soldering techniques are to prevent bad contacts or impurities as this is sensitive measurement equipment.
A had an awesome (for its time), Hyundai L90D+ monitor, and used it for ~8 years.
One day it turned and stayed off, sent it to some local shop for repair, and the tech told me that he added another light control circuit and, my brightness had to be adjusted via an external control. He also said that two ICs damaged, and he cannot source any.
I got pissed, found the parts, removed the other abomination and changed the damaged parts myself.
The monitor came back alive for 30 seconds and then died again.
It had no leaky caps, no visible damage, nothing on the board.
Had to trash it.
So, YMMV.
One day it turned and stayed off, sent it to some local shop for repair, and the tech told me that he added another light control circuit and, my brightness had to be adjusted via an external control. He also said that two ICs damaged, and he cannot source any.
I got pissed, found the parts, removed the other abomination and changed the damaged parts myself.
The monitor came back alive for 30 seconds and then died again.
It had no leaky caps, no visible damage, nothing on the board.
Had to trash it.
So, YMMV.
The board had probably developed a short somewhere because one of those tiny ceramic SMD capacitors had failed which is very hard to tell just by looking at it. Or the PCB substrate may have degraded, allowing two traces to come into contact but this is less likely.
The tech probably figured out that this was happening but was unable or unwilling to isolate the issue.
The tech probably figured out that this was happening but was unable or unwilling to isolate the issue.
> The tech probably figured out that this was happening but was unable or unwilling to isolate the issue.
I suspect. It was just a run of the mill repair shop. If he had found it, it would have warned me when I told him about my future intentions.
I suspect. It was just a run of the mill repair shop. If he had found it, it would have warned me when I told him about my future intentions.
Since the days of ISA and DIMMs I've been 'fixing' things myself. I also do all sort of 'handy-man' work at home.
Being 'technical' I'd still suggest evaluating things before engaging to them.
Some repairs aren't worth it. this is per-basis calculation based on your capabilities, experience and time.
So the important word is... MAY be easier... maybe it won't be easier than you think ;)
Being 'technical' I'd still suggest evaluating things before engaging to them.
Some repairs aren't worth it. this is per-basis calculation based on your capabilities, experience and time.
So the important word is... MAY be easier... maybe it won't be easier than you think ;)
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I’ve don’t similar fixes over the years soldering replacements for dead components and changing the CCCL in a laptop.
I was surprised by how simple and spacious the boards in these displays are, easy for an oaf like me to replace components on. Just find where the magic smoke came from and order a replacement part for pennies.
I was surprised by how simple and spacious the boards in these displays are, easy for an oaf like me to replace components on. Just find where the magic smoke came from and order a replacement part for pennies.
I just had a newish (but out-of-warranty) LG 4k monitor go bad on me. The picture went mostly dark, with a few streaks of white. I figured how to take off the back panel, but then got them stuck removing the EM shield covering the main board. I got all of the screws off, but then it wouldn't come off.
I've got several broken electronics that I'd love to try to repair someday, but they don't have any screws and they are obscure enough to not have any tear-down guides to tell me if a heat gun would help. Cutting them open could just leave them unappealing to use, and thus I wasted my time.
I like working on things that are broken: you break it such that you can't get it back together again, who cares, it was broken anyway. What I worry about are things that work but need maintenance - mess up the oil change an a good car and you destroy the car...
In short, get in there are see what happens. Sometimes you will destroy something, but right now it is landfill material so you didn't lose anything. sometimes it is an easy fix.
In short, get in there are see what happens. Sometimes you will destroy something, but right now it is landfill material so you didn't lose anything. sometimes it is an easy fix.
How do you find a broken capacitor on a board?
The article says it was clear that the cap was "swollen" but how do I know what a swollen cap looks like?
And what if it's broken but not swollen?
The article says it was clear that the cap was "swollen" but how do I know what a swollen cap looks like?
And what if it's broken but not swollen?
It's very noticeable when you pay attention and compare it to the others. There are generally a lot of capacitors there, and only one or two will be swollen (the top part is supposed to be flat or even slightly curved inward, if it's curved upward, it's bad). Really, if it even looks slightly out of place, change it, capacitors are dirt cheap.
I'm not sure it can be broken without being swollen, or at least that's not a frequent failure mode.
Having repaired a few displays just like that, I can say it's really easy provided you are able to open the display and solder on a basic level, which anyone can learn in an afternoon.
On the other hand, not all display will be that easily repaired. Sometimes, you cannot easily identify any swollen capacitors, or there is a burn mark somewhere else, or something else that you cannot identify (and thus order a replacement for). In those cases, unfortunately it generally doesn't make sense to bring it to a shop to be repaired by pros.
I'm not sure it can be broken without being swollen, or at least that's not a frequent failure mode.
Having repaired a few displays just like that, I can say it's really easy provided you are able to open the display and solder on a basic level, which anyone can learn in an afternoon.
On the other hand, not all display will be that easily repaired. Sometimes, you cannot easily identify any swollen capacitors, or there is a burn mark somewhere else, or something else that you cannot identify (and thus order a replacement for). In those cases, unfortunately it generally doesn't make sense to bring it to a shop to be repaired by pros.
look at the other capacitors. the top is really flat. you can even spot those that start to fail because light will reflect slightly differently on top of them.
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Consider sharing this on repair.wiki.
Opening Amazon and buying a new one is even easier and you end up with a more modern and therefore better product.
"modern" does not imply "better" anymore, for at least a decade now.
Think of SmartTV, microwaves, or every kind of consumer electronics in general.
Think of SmartTV, microwaves, or every kind of consumer electronics in general.
I do think you should open your mind a bit. Smart TVs are pretty terrific, I can just cast whatever I want across the room and bam, it's on the TV. Friends can come over and share the input. I can lay in bed with nothing but a remote and browse my plex library.
I used to go along this line of thinking, and had a "dumb" TV for a long time. I would spend hundreds of hours trying to get a PC/xbmc/kodi setup with a remote control to be comfortable, but always required a keyboard and mouse next to the TV. In the end it was a waste of time and I wasn't enjoying my TV as an entertainment device.
When I finish work, I want to sit down and just have everything work. I don't want to have to keep getting up and pressing buttons and messing around to get a myriad of supplemental devices of varying quality to work. I just want one single device, on the wall, with a remote.
I used to go along this line of thinking, and had a "dumb" TV for a long time. I would spend hundreds of hours trying to get a PC/xbmc/kodi setup with a remote control to be comfortable, but always required a keyboard and mouse next to the TV. In the end it was a waste of time and I wasn't enjoying my TV as an entertainment device.
When I finish work, I want to sit down and just have everything work. I don't want to have to keep getting up and pressing buttons and messing around to get a myriad of supplemental devices of varying quality to work. I just want one single device, on the wall, with a remote.
What you didn't include: the data gathering and the ads. tons of ads. I interacted with smart TVs before, but when i pay for it and it displays me ads in the UI, its an instant return. I'll have none of that shit.
And don't get me started on weird bugs that i can't even fix myself. Stuff like my dad's TV randomly outputting 1-2 seconds of audio of the last selected sender /while being turned off/. Audio only, with the screen turned off. Just a few moments. Nightmare fuel when its dark and you are sleeping in the same room.
And don't get me started on weird bugs that i can't even fix myself. Stuff like my dad's TV randomly outputting 1-2 seconds of audio of the last selected sender /while being turned off/. Audio only, with the screen turned off. Just a few moments. Nightmare fuel when its dark and you are sleeping in the same room.
I don't experience ads with my TV. I don't understand why this is an often repeated point. I've had three so far (due to moving countries), and never experienced this "tons and tons of ads" thing I see people complain about. It's always just been a UI and some apps.
Regarding data collection, who cares? Just get a pi hole if you really care about that.
Also you are describing a fault that can occur with a dumb tv.
EDIT: okay. I found this https://external-preview.redd.it/DcKcaASCdFkfM-eK5pOiu6DIOZb...
I have a samsung TV and I do not see this. Perhaps this is a region thing. I've lived in The Netherlands and the UK and not experienced this.
Regarding data collection, who cares? Just get a pi hole if you really care about that.
Also you are describing a fault that can occur with a dumb tv.
EDIT: okay. I found this https://external-preview.redd.it/DcKcaASCdFkfM-eK5pOiu6DIOZb...
I have a samsung TV and I do not see this. Perhaps this is a region thing. I've lived in The Netherlands and the UK and not experienced this.
Dumb TV + Streaming stick is the way to go. Bundling your TV (hardware) with your smart TV (software) is a recipe for disappointment and frustration 2-3 years down the road when the tech evolved and your TV manufacturer has lost interest in supporting your model (looking at you LG)
I don't completely disagree. VGA should have been removed from monitors 10 years ago. Some companies still buy new monitors and hook them up via VGA. That should be prohibited by labour laws. The image quality wasn't good enough to be used for an entire work day in 2010 and it certainly isn't acceptable today.
Tens years ago I argued with a previous boss that it didn't matter how cheap the monitor was, he shouldn't force anyone to use a VGA monitor and hurt their eyes when DVI was available and only slight more expensive.
That being said, if you need a VGA monitor, perhaps for some retro computing or a system that only supports VGA for some reason, it's better and cheaper to just fix it, if possible.
Tens years ago I argued with a previous boss that it didn't matter how cheap the monitor was, he shouldn't force anyone to use a VGA monitor and hurt their eyes when DVI was available and only slight more expensive.
That being said, if you need a VGA monitor, perhaps for some retro computing or a system that only supports VGA for some reason, it's better and cheaper to just fix it, if possible.
I think with VGA, being analog, the image quality depends on the specific hardware. I've used monitors on 1080p 60Hz using VGA cable and it's been fine. On the other hand, I've also had poor image quality (ghosting) at the same resolution with a different cable and monitor. So it is possible to have decent quality on VGA, but not guaranteed.
I think these days that you don't really pay extra to have an HDMI port on a monitor. As HDMI is signal compatible with DVI, you can just use a passive adapter if your computer only has a DVI output.
I have considered digital inputs (DVI, HDMI or DP) mandatory for any monitor I have purchased for myself since 2010 and when people ask me for advice on monitors I advise the same.
I have considered digital inputs (DVI, HDMI or DP) mandatory for any monitor I have purchased for myself since 2010 and when people ask me for advice on monitors I advise the same.
> or a system that only supports VGA for some reason
AFAIK, nearly all modern servers only have VGA, serial, network, and a couple of USB ports, so it's much more common than you think. Of course, most of the time you'll be configuring them through the dedicated management network interface, so the VGA and serial outputs are mostly a fallback.
AFAIK, nearly all modern servers only have VGA, serial, network, and a couple of USB ports, so it's much more common than you think. Of course, most of the time you'll be configuring them through the dedicated management network interface, so the VGA and serial outputs are mostly a fallback.
Just like 3.5mm headphone jack. No.
Well, people complain about Bitcoin to kill our climate but on the other hand have no problems to buy new monitors when it's not necessary ...
Defective capacitors are a common plague in modern electronics, and the culprit is always the capacitor: the market is literally invaded by rubbish quality capacitors, and swapping a bad quality one with another bad quality one guarantees it will fail again one day, so buy only reputable parts from reputable vendors; avoid online purchases of branded parts from unknown resellers (pretty sure that 99.999% of Nichicon or ELNA capacitors sold by any Aliexpress, Ebay, Amazon, etc. sellers are relabeled fakes); pay them more but pay them once. A web/image search for "counterfeit capacitors" works better than 1000 words.
Anyway, when shopping for (hopefully genuine) electrolytic capacitors, respect also the temperature ratings. Capacitors mounted into a power supply are exposed to higher temperatures, so always choose the 105c degrees type. Capacitance is usually not critical; electrolytic capacitors accuracy can be worse than 20%, and that's not a problem because they're not required to be accurate for their job, so if you don't find the exact value, you can safely swap the part with one with slightly higher capacitance; same for the rated operating voltage which can be higher (not lower!). Low ESR rated ones are preferred; if you can, buy them instead of generic ones.