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- Опубліковано 6 жов 2024
- Yet another dumpster diving LCD monitor repair.
This time an LG Flatron monitor with bad caps.
Using the Bob Parker ESR Meter
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Dave, please do more fault-finding and repair videos! They're very educational!
Dave, there is a simple way to make the cap fail in 2 or 3 years... Filter most of the ripple but leave just enough to kill the electrolitics! However you can fix this by just adding a few 100nf caps near the filtering coil to get the edge a little smoother. This lengthens the life of the cap's considerably.
Unbelieveable. I found almost exactly the same monitor (A silver LG Flatron) exposed on the street about 6 Years (or even more) ago. I took it home, figured out that the caps were bad (just by looking - didnt have an esr meter that days), replaced them and the monitor is still running. This was my first Monitor repair i ever tried.
Well done Mirko! And thanks for helping keep our planet GREEN rather than toss another failed Chinese manufactured piece of electronic equipment in a landfill junk heap! Restoring previously failed electronic equipment back to fully operational condition approaches being Godlike in my humble estimation!
@@mikeadams110 soon china will not sell anything to the usa anymore, don''t worry.
Totally outstanding video. Well done mate! Just purchased an ESR meter last week which has literally paid for itself several times over already. I'm astonished how impressively well they work without having to remove the caps under test out of circuit anymore. What a great time saver! By the way, I've gotten the same readings and results even once any bad caps have been removed and then tested a 2nd time around out of circuit. These devices work amazingly well and are worth their weight in gold. Don''t know how I got along until now without one. Makes tracking down the failed caps a lead pipe cinch. I agree the bad caps are most often bulging at their tops but definitely not always. Quite a few looked entirely normal and respectable from all outward appearances but measured unquestionably faulty on the ESR meter. It's truly a switching power supply bad cap divining rod of sorts and bench tech's magic wand.
Hello my dear friend. I made a meter for myself according to the manfred scheme. very pleased with the result !!!!
I try to fix all sorts of industrial gear at my work and I just really started at this a few months ago.
It's frustrating to have a board that's not working and not seeing anything obvious. I'm now convinced of the effectiveness of esr meters after this video and I'm going to convince my employer to buy a meter in order to increase my success rate in board repair.
Electronics repairing except tools needs extra more human senses!
The problem with bad caps on power regulation is that failing cap may have caused too high voltage to the IC and destroyed those for good. A well designed board wouldn't do that but many boards are not well designed.
@@MikkoRantalainen please tell me what I C stands for I had one blown cap on a Jensen TV set and I fixed it put a new cap in and it's still no picture or sound so I'm just curious what else might be damaged for me to look at all the other caps look good but I haven't checked the with a estimate meter
@@johnmitchell8925 IC means integrated circuit. Basically the stuff that most people call "microchips". The problem with IC is that those really cannot handle overvoltage and many poorly designed power sources output too high voltage to one of the power rails going to IC which basically frieds the internal parts of the IC. The only way to fix the device is to replace all the affected ICs.
If you don't have schematics for your device, figuring out which ICs are broken is going to be hard. All the chips are usually just okay visually because we're talking about 2 V instead of 1.3 V to CPU, 9 V instead of 3.3 V to memory and so on. Definitely not enough to cause charring but too much to cause just temporary failure to the chip.
Wish you could do a video on the difference in quality between consumer products and military or avionics grade electronics. Thanks I enjoy your videos.
im learning so much from these videos i have a tv thats malfunctioning its one of those element hdtv's all of a sudden it just got much less bright recently so today i took the cover off the back to check the main power supply board and saw... a single capacitor with a popped up top.. now i know it needs to be replaced and im already looking online for parts, and this video showed me how easy it is to de-solder the capacitor and that im going to need to buy a soldering iron some solder and one of those wick things.. beats taking it to someone to pay them like 70 dollars american to replace a single capacitor.
Not necessarily caused by the choice of a a bad component.
The SAMWHA WL-series seems to be a decent series of high temperature, long life, low impedance capacitors.
However, the capacitors probably failed by a too high ripple current, causing excessive temperature rise, resulting in premature failure.
The power supply looks like a flyback converter. In general such power supplies have a relativity high ripple current on the main output.
When you look on the PCB, you see, that there is room for two extra caps, so the overload of the caps might have been caused by a wrong design choice or production choice.
When two capacitors were left out, e.g. because the ripple voltage was low enough, the ripple current through the remaining caps doubled, possibly resulting in premature failure.
Love this guy! And btw thanks so much for doing a real world example of how to use the Bob Parker ESR meter. I had considered getting this model but I had heard or read that you did have to take capacitors out of circuit to get accurate reads and that made it less of a desirable product. Your example has changed my opinion. Ordering mine in the morning. Thanks Dave.
Recently I got a faulry monitor to repair in the repair bussiness that I work and no one knew what's wrong because all the caps on output were looking just fine.
Even tho I don't have an ESR meter, from experience I knew that they were the fault and the monitor started working fine after I replaced all 4-5 of them :D
I will get an ESR meter soon :)
Look up ESR meter on Amazon/eBay can get a cheap works great ESR meter for under $30.
"Oh-ho... look at that one.. That's a shocker!"
Brilliant.
I effing well love your vids. You rock sir. You rock.
Man, this video is such a good example of how work should be done. Please, keep up doing this, sharing with us, there is a lot to learn from you.
Best regards.
Hi! I recently recapped the power supply of 2 Allen-Bradley PLCs and while none of the caps were bulging, they had no storage capacity at all. They were powered by an UPS and just the time it took for the relay in the UPS to switch between mains and battery, the PLCs made a major fault and would stop running.
you gotta love it when thy strap electrolytic caps right onto the the side of the biggest inductor on the board
neat! i learned a lot from this video about fixing these things and ESR meters! I didnt realize that when these things break its such a high probability that it's gonna be the caps that are bad. If only they used some good ones they'd probably last years more! I'd probably enjoy seeing a few more of these videos!
that's a very handy meter. I'm working on a Yamaha mg16 and a Behringer mixer. real pain in the ass, so many caps. I hate when a cap goes bad and it doesn't bulge, damn headache.lol. nice video by the way.
Hi Dave
I know this is a bit late to comment but only just recently found your blog and are slowly working through all your videos.
You probably have been told this already or worked it out for yourself later but you don't need a tool to unclip an LCD monitor.
You can probably google the correct / easier way but a service manual shows how it's done with the screen facing up and using your fingers to lift / unclip the bezel. Much quicker and easier. Done hundreds; no exaggeration. I'm an oldish? 56 years old tech.
Gonna watch the Peak Atlas ESR70 review next as I have one. Love it as well as their semiconductor analyzer which I also have.
Loving the blog. Thanks :-)
Terrific close ups of the de-soldering - you've really got the imaging technology working sweetly now.
Thanks for the video. I have a LG Flatron W2243T that isn't powering on. Nice picture, too bad they are built cheap. I thought about tossing it, but I'd like to replace the caps in it.
ESR meters are great. I wish I had more training on troubleshooting stuff like smd stuff. I have fixed a few things like tvs and monitors. I even found a use for the ESR meter for detecting bad solder joints. Maybe it was just luck but a bad solder joint gave a high ESR.
On a fender deluxe reverb from the 70s.
I greatly respect your knowledge & techniques.....you help many people. I sometimes watch your videos with the audio shut off. The incessant chatter & irritating voice is more than I can handle. Nothing personal, just one man's observations. Keep up the good work. Cheers!
Not sure if you mentioned it but when your measuring these in circuit make sure there are not several in parallel because they can check good even though one is bad. Also some of the esr meters on the make discharge the caps as part of there test which is nice.
It's important to remember that you don't have to remove them UNLESS they are in parallel :)
If they're in parallel I've had a completely blown cap pass with flying colours.
That looks exactly like my ESR meter. Was yours a commercial unit or a kit.
I built mine probably 25 years ago, and it has been the most used piece of test equipment on my bench.
12voltvids where can I find that meter?
Mike Lornitis Watch 6:10, he tells you exactly what the meter is. Google is your friend!
@@sitinrol www.altronics.com.au/p/k2574-esr-meter-kit/
Great vid Dave. As for snap cases, not only do they save the cost of the screws, snap cases are MUCH easier and faster to manage in an automated assembly process, which I imagine is the real reason for avoiding screws.
Can be all sorts of weird intermittent or constant thing, or just dead. No way to predict what ripple on the power rails will do.
Afaik it's common to use tabs instead of screws, not because the screws are expensive, but rather because it's more labor intensive to use screws. It's much faster to snap things together with tabs, so they save a lot on labor costs.
+roidroid Ya maybe for them, but for us got to take it apart and do not know exactly where hte tabs are or what the method is to "unsnap" them. Screws are self-evident.
indeed. Appliances aren't made for ease of servicing, they're made for cheap manufacture. AFAIK Labour is one of the major costs in the manufacture industries, so any savings they can get there pays off BIG. If a part can be redesigned to save a mere 1 second of labour time, they'll do it.
They probably save so much on labour by using tabs, that it more than offsets the costs of just replacing all faulty appliances with new ones (instead of servicing them). So in the end it's the more profitable option to make non-serviceable but very-quick-to-assemble appliances.
Panasonic perhaps. But there are maybe 3-4 equally top quality ones.
The plastic hinge design saves them assembly time by quite a lot. Also the cost of screws will add up, imagine they manufacture 10million of the same models, each screw costs $0.001, saving one screw that's $10K, those screws usually costs more than just a cent, so you get the picture.
That logic could apply to literally *any* component tho
The videos look a lot brighter with the new lighting Dave! Good job
Would like to know the same, but I think most important is the ESR. Looking at datasheets for caps (if you don't get extensive datasheets for the caps of a manufacturer, put that manufacturer in the "no, thanks" category), higher voltage rating does not mean lower ESR.
The diodes are mounted at odd angles to prevent "mutual inter-component resonance," which, if left unchecked, the slightest deviation of smooth convective airflow would cause the diodes to start flailing about, bashing into each other and nearby components until turned into dangerous shrapnel. Yass.
In 2011 I bought LG monitor, and it works to this time.
The reason is that this monitor get power from external PSU.
Yes. The internal switching power supply units are dog crap which will eventually self-destruct due to an inherently flawed design relative to the feedback loop. It can run away under certain adverse conditions and blow out any components in the path of least resistance which sink a sufficient level of current necessary to destroy themselves. Those, most typically being electrolytic filter caps.
Yeah and those classic CCFL backlight transformers are hot like hell.
Last time I fixed monitor where transformer overheated and secondary wiring was burned, and by some time there was sparking that probably damaged CCFL tube and inverter IC was shutting down after 1 second, even when I repaired transformer and tube was lighting, to fix it I had to add 10pF/1kV capacitor in parallel with defective tube.
But before I figured it out I spend few hours, IC based faults are bitch to troubleshoot, there was even no datasheet for that IC...
your right. it seems like they put caps that are made on purpose to dry out in short time since i had to replace every electrolytic capacitor on my mother board. what quality can you expect in Tier 5 country, where noone is checking the quality of products, and yet we are paying the same price for the computer parts as in US and EU but the quality differs greatly. i bought GForce 9800GT for $280US (same price as the original) but it was made by Inno3d. crap quality failed in the first 5 months.
I put new caps in a Westinghouse monitor it turned out good.
Hi Dave,
I haven't seen all your videos yet, but it would be good to go over the safety aspects of discharging the capacitors. How it's done etc, you mentioned you have a bleed resistor. Enjoy watching your videos . easy to follow and always exciting the ESR meter looks like a product I'd buy. Do they make multimeters with ESR functionality?
No, it doesn't really work for caps in parallel. None of the caps in this video were in parallel.
Hi Dave. Yet another great video.. Though I'm getting a little worried about ya mate, going through dumpsters and all..
Yep the old monitor cap problem.. That old chestnut!!
Question: Who would you say is the best manufacturer of aluminum electrolytic low ESR caps broadly speaking ?
Tried fixing the 22-inch version of this monitor.
Replaced all the bulged caps, but in the end it was a defective transformer (that thing covered in yellow tape). It was making periodic clicking noises when I connected it to mains. Couldn't save the monitor unfortunately, and replacement power-boards go at around 70 Euro on ebay. Not worth it.
should have tried the 4-wires power module that can be ordered online, maybe your unit had saved...
Caught your vids for the first time and want to thank you the presentation was right along my novice speed very thankful from hear up-over country cheers and 73s phil K1PAS
I use Panasonic FM... in SMPS repairs they are great caps!
great vid! thanks !
Sounds like cause for a review ... but get one that's regulated (temperature controlled). When desoldering you need plenty of heat especially when the the boards have large areas of copper designed as heatsinks. Some wet on your iron helps too
EEVblog => Hi Dave. I am watching your blog for years now an love it. My favorite segment is videos like this one but also mailbag ;-). Can you make a video about measuring esr with a function generator and a scope? That would be interesting! Big thanks and go on with your great blog!
I absolutely love these videos of yours man, great work :D
If measuring caps in circuit result is total for all caps in parallel? Definitely what happens measuring capacitance. The first bad cap measured was .23 the other almost double at .61.
Exactly correct Bob. Caps which are parallel in-circuit are unquestionably going to throw off the reading even when using an ESR meter. But you'll find that scenario doesn't occur often enough to worry about most of the time. Just be aware it CAN so always be on the lookout for that possibility. In which case, you'll obviously need to take any such parallel caps out of circuit in order to get an accurate reading on the ESR meter.
You mentioned ESR meters can work in circuit because they send a low voltage at 100KHz signal but what about capacitors wired up to inductors? wouldnt this affect the measurement?
These cap issues just don't go away. They nailed me with ECS computer boards around 333MHz and then 1.4GHz and now with the Asus M4A785T-M where the Tk ATWY 938A 6.3V 820uF caps are puffing and then the computer is unstable.
I got a Socket A motherboard that when used the computer locks up at times. It continues to run but it becomes unresponsive to input. Basically mouse and keyboard inputs cease to work. I got one less than flat cap out of all the ones on the board right next to the ATX power connector on the board. I don't have a ESR meter, but if I can find a cap off another board that matches the voltage and capacity of it would there be any harm in replacing it. With these caps soldering should be easy even for someone as unskilled as myself. Will to try to get a little more life out of that system for some retro gaming. I guess that could be consider retro at this point in time lol.
They neglected to clean up the board artwork when they changed the heatsink & TO-220 package. Samwha are usually crap. I usually LCR and ESR check lots of caps.
Hi buddy. Thanks for sharing all your videos. Sometimes it is hard to follow u 'cause you go really fast but I wonder when I can get that ESR Meter. I can not find it.
This is the same kit: www.altronics.com.au/p/k2574-esr-meter-kit/
Beauty ,I love it,You have learned me show much over the year bud and I love repairing stuff for family and friends and when I was a lad I was told I would never be a eletronics guy cos of my red/green colour blindness, prooved em wrong :)
I just made my first monitor repair by replacing 3 caps. :)
two times i am fixing my MSI P43 Neo-F mother board from blown or dry capacitors in the last 6 months without using ESR meter :( i wanted to build one but if i had money to build it i would certainly had money to buy new mother board instead of fixing the old one.
Dick Smith Electronics... Now there's a name I haven't seen since the early 1990's! Looked it up on the internet, I didn't know he was Australian! This video is a good tutorial on measuring caps in a switching power supply. Sometime there's more than 5, and that's where it can get a bit tedious. At least for me. Great Video!
Cool dumpster diving can reward.. TheSignalPathBlog scored a HP 8648C with a cap that somehow jumped off the board. Myself I haven't found much.
I got a LG Flatron L1953HM.. The build quality is a bit cheesy.. But the panel is good. it gives a very nice picture, considering it's not really a high end monitor
It seem to me that having a small stock of Nippon Chemi-con output filter caps is a good idea. I was once forced to repair a computer power supply (after some 10 years of use and overloading-a-250W-supply-down-with-GTX-650-Ti abuse) and the culprit was a busted Capxon cap. Whacked a Nippon Chemi-con one into it after clearing the overload fixed it.
I couldn't agree with you more Max and have posted that same excellent point higher up above.
thats what i was concerned about. i think he did not mentioned it and those output caps are usually in parallel, aren't they ? I was surprised that he even got different readings.
Maybe these are different output rails ? 12V and 5V or so.
Seeing a lot of Samsung SA450 24" LED monitors going. Often not that old either. They have separate powerpacks, so they aren't the issue.
Capacitance meter, of a fluke 115 for example, is is not as good as an ERS meter? Thanks.
i have to get one other those meters, nice trick for checking caps
Anyone who feels capable may build ESR meter. Just search google for "arduino esr meter". By the way i repaired an LG monitor by searching google, not measuring elements. Not the best practice, but it worked. Changed the 2 capacitors, which are common to fail according to the Internet and it works again
If you go to higher power PSUs (PC power supplies), it's quite common to have a few in parallel on each output rail. Often lets say 3 1000µF in parallel have a much lower ESR than one 3300µF.
Btw. I wouldn't measure anything in circuit either (except maybe a diode for a short).
+1 for Panasonic. I have gone through hundreds of them with no failures to date. Rubycon is also a top brand, but they cost more than Panasonic.
No No No No Dave! Just checking a capacitors ESR is not enough! At the very least you should have checked their capacity too! Capacitors that fail from high ESR usually bulge, leak electrolyte or explode, essentially they destroy themselves!
But high EPR (parallel Resistance) won't show signs like an ESR failure, they always destroy the next component in line!
If the capacitor is rated for 100uf but shows 200uf or higher, then it has high EPR and should be replaced ASAP! Otherwise you might end up looking for an unobtainium IC!
I haven't tried it myself but I'm going to solder a resistor across the legs of a capacitor and test it's capacity both with and without the resistor! I reckon that I should see a higher capacity value with!
No matter where I look on UA-cam, I see people check capacitors with just an ESR meter which returns a good value but when they check the same capacitor for capacity, it reads high! There's no such thing as an overachiever when it comes to capacitors! It has high EPR and it's going to destroy something else!
There's an excellent LCR Bridge Meter on eBay for $95AU that will tell you capacity, ESR, EPR (DC leakage (drain)), phase angle and Quality all on the one screen at the same time! Without this information you really don't know it's condition...
XRayTonyB did an excellent video showing how it works, this is one tool that should be on everyone's bench! Mate, it's really that good. More awareness about this particular capacitor problem needs to be made! An ESR meter will only get you so far!
Just take a look at the chared PCB, a capacitor with high ESR won't cause that! But a capacitor with high EPR is essentially passing DC to that transformer, it's most likely saturated and getting to hot 🔥. As a result, more current is drawn through the diodes causing them to heat and up goes the ESR on what could have been good capacitors.... EPR is a bigger problem with equipment failure than ESR....
I have been working on this problem for years and now that I have an LCR Bridge Meter, there are no more capacitor mysteries...
I'm sure that you have seen Paul Carlson's capacitor tester, it tests for EPR, not ESR... That's why it's so good at what it does... This is a worthy topic that requires more awareness to... I would love to see your take on the matter... Take a good capacitor and put a resistor in series and test it, then place the resistor in parallel and test it again and see what you get?
@@jayytee8062 no I don't, all that I did was search for LCR meter on eBay... There's two types, one was silver aluminium with a lime green screen and the other is black aluminium with a blue screen... Although the picture didn't show that the screen display was blue... I asked the seller for another picture with it turned on... The black one has a built in LifePo4 Battery and charges by USB... They were selling for around $100 price mark back when I got mine, I still love it, it gives all the details that you actually need on one single screen!
Love your videos man. Keep up the good work..
What about checking poly caps and the like in circuit. Old TVs horizontal or vertical yoke caps.
Damn, wish I had a dumpster like yours near me, Would love to pick up free monitors.
I've repaired hundreds of monitors, this is actually very very very stock standard typical for computer monitors WHEN they fail
Almost always
first check voltage in and voltage out
then
visually inspect the caps
discharge caps properly
Check the fuse for continuity and resistance
Check the ESR on the caps
then just for good measure go around the board
Check MOSFETS and DIODES and the bridge rectifier if it exists as a package
for voltage in and votlage out
if you can't see anything else
replace caps
re check volts in and out and at rectifier
more times than not....... Youv'e fixed it
Follow the link to Bob Parkers web site.
Very Good Mate, enjoyed your videos.
Hello, I have been following your videos, you have one of the most complete labs I've seen, I found this ESR meter interesting, where do I get one of these? I'm still an electronics student and I'm still far from having the necessary equipment, but I've seen this device helps a lot in basic repairs.
Love your videos. Thanks very much for sharing them with us.
looking forward to see you repair a monitor that's not a capacitor issue.
thanks to this video ive just bought an esr meter. very interesting
too bad they don't sell that K7214 kit anymore.
This is the same kit: www.altronics.com.au/p/k2574-esr-meter-kit/
Looking at the graph at the front of the meter would have convinced me that 0.2 ohms would have been a pass.
Bulging is the only thing that would have done it for me.
Hi Dave...I found interesting the large traces for power have these "solder stripes", I guess they are to hold more solder than a complete open trace right? Could you test it? If yes, please post in here the link, so I might see it! thanks!
A monitor is for life not just for Christmas well if there's decent caps or a mate like dave
what would be a OK substitute for a 450v 10uf cap for element LCD display, I have some laying around and you said I can go up but not down. Thanks and you are a whiz bro! gj!!!
Technically, most "general purpose" caps are rated at 20% tolerance from their designated outer case marking relative to capacitance value. This means a brand new cap fresh out of the factory rated at 1000uF could actually measure anywhere between 800uF to 1200uF being quite a wild deviance from spec right off the bat!
In most cases, they'll prove more reasonably closer to their preferred value rating considering today's modern plants exercise some degree of component quality control.
Nonetheless, be sure not to exceed that inherent deviation any further from the component's original ideal rating, meaning 10% higher or lower in value from spec. Bear in mind, capacitors of any kind (electrolytic, ceramic, epoxy, trimmer, etc) serve one of 3 primary roles in electronic circuits as detailed below the next 2 paragraphs.
Arbitrarily changing the preferred values from spec in any of those roles will absolutely cause a measurable negative impact upon the circuit's performance to some degree. Whether acceptable or not is entirely a gamble and wild guess at best.
Taking that kind of unnecessary risk simply isn't worth blowing out a more expensive (perhaps harder or impossible to get overseas component) somewhere up or downstream within the circuit such as a specialized IC, microprocessor, dedicated microcontroller chip or Laser diode.
1. decoupling capacitor. Used in this role a cap will remove any DC component (meaning plus or minus DC bias) an AC signal may be riding on back down to ground (meaning zero as in baseline on the oscilloscope) rather than riding up at +5vdc for example.
2. filter capacitor. Used in this role a cap will filter-away (meaning dump to ground) any specific undesirable AC signals (meaning unwanted noise or potentially false triggering signals) such as leftover 30hz half-wave ripple in a DC power supply. This "cleans up" the DC purity and stability quite dramatically just prior to more precise IC regulation (using an LM7805, LM7812 or LM317 for example) being the final back-end stage in any quality power supply.
3. timing capacitor. Used in this role the cap sets a highly precise desired frequency in an RC (resistance/capacitance) network circuit. In this case and role the capacitor's value shouldn't be varied even the slightest from spec without causing drastic performance trouble or even device failure.
Rather than arbitrarily deviate from the original circuit specs purchase a low-cost ($20) bulk assortment of the most commonly used electrolytic capacitors to keep on hand of which there are around a dozen. You're typically given 8-10 of each value in such assortments. Be sure to order the low-ESR variety if they're going to be used in any switching power supply unit (SPSU) all of which inherently demand and rely upon this special requirement.
You'll find 99% of the time the caps which fail in a SPSU are nearly always the general purpose rather than low-ESR variety being why they suffered an early demise.
That harmful concession nearly always having been made by the manufacturer being a tactic by which to minimize a product's cost. It's quite revolting and rather unjustifiable considering they're saving just pennies on the dollar at the expense of a product's overall life expectancy.
So spend those few extra pennies to get quality replacement caps which meet specs. In which case, they'll last for decades rather than just a year or two after warranty expiration at best.
Yes, certainly, but you'd expect them to last ~ their rated lifetime if used within specifications. Which is not the case with certain crap that's used to save a few thousand bucks in production.
ive got a semi dumb question for you.. ive got whats called a 'voltage stabilzer' unit which is an optional device used for Tig welding when added on to a basic A/C stick welder. This device uses a tesla coil and a mica cap in which the cap shows signs of the 'resin' leaking. This unit was made in 1967. The cap is imprinted with ratings that say 5000v 6.0 a and .01 mfd .. is there a modern replacement available for this .. ive looked online and havent come up with anything other than used
Dave keep on the good work
Watching this on the exact same monitor.
Great video, thanks for making it. Keep making these videos, your great and your video are greatly improving.
I had to do this with an LG monitor I had, so I replaced them with higher grade caps.
Dave, what are you doing with all those monitors? You must be stacked to the rafters by now.
where did you get your ESR meter? love your videos
Assuming your body has got an impedance of 1000 Ohm there are 330mA of current at maximum. The time constant of the cap is about 50ms, which means that it gets discharged pretty fast, while voltage and current drop very fast as well (about 90% within 100ms). I don't think that this is lethal for a healthy heart but I wouldn't like to test it as well. It's definitely dangerous.
Found an interesting paper on that on the site of alcatel-lucent:
Google for "Effect of Electric Shock on the Heart *"
The low voltage wont bias any semiconductors, however what if there is a resistor in parallel with the cap under test ?
The people that make the decision to go with the snap-together cases are never the same ones who have to open up the damn things.
@EEVblog, Dave, I love my collection of various sizes of solder suckers on thru-hole. Any reason you seem to prefer solder wick?
Great video! I have a question. Can I potentially hurt myself with fully charged 330v 160uF photo flash cap?
yes you can hurt yourself
Wow, your power proved that it had another major fault, it displayed Windows! Thanks for the great vid, I ordered an ESR and I will dive into a couple defective monitors I have
When using an in-circuit ESR meter, is it really possible to check a specific cap that is in parallel with other caps, without having to first desolder and remove the cap under test? What makes the ESR meter check only the cap you put the leads to, and not the one half an inch away connected in parallel on the board?
hi dave could do a full review and tear down of the esr meter by bob parker.
thanks gary from the uk.
This is a great video for teaching technique. Thanks!
Hello Dave
I like your videos.
If possible , I would like you to clarify one doubt me ?
Is not risky measure the capacitor ESR directly on the board because I was told that damage the measuring equipment.
Because the capacitor can still load
Or that equipment , can specifically make the capacitor ESR measurement still on board
I hope you can understand me , because I used the google translator , I do not speak English
Continue with the good work
Thank you for your attention
Best regards
Zenilto in Brazil
Ele falou no vídeo que é pra descarregar todos os capacitores antes de testar.
Those rubbish screens are not supposed to be repaired. So, that is why the designers do not care about being able to open the case in order to make repairs easy. We are supposed to keep on buying new stuff.