LG 50PG30 Plasma TV PSU Capacitor Replacement - Page 1
Forum section: electronics / repair

author: nirvdrum
author_rank: Contributor
timestamp: March 26, 2021, 04:04:15 am
content: I have four clearly blown capacitors (10V 3300 uF) on the PSU board for my LG 50PG30 plasma TV. If it helps any, the board is EAY43521401 (PSP-J703B). The TV was manufactured in 2008. They're all Samwha capacitors. I still like the visual quality of the TV, so I'm inclined to repair it.Replacing the four blown capacitors is straightforward. Where I could use some guidance is whether to replace all the other electrolytic capacitors. I've seen conflicting recommendations: 1) replace them all and be done with it; or 2) only replace the ones most stressed, since the others are unlikely to fail. I don't have an ESR meter. Likewise, I don't have enough knowledge to trace back each capacitor and determine what it's used for.I have gone through and identified all of the electrolytics on the PSU board. They're all 105C and I assume low ESR (I didn't actually track down data sheets for each). The sizes are probably off by a little (I used calipers and some are a bit awkward to get at). The list is:Code:Voltage (V) Cap. (uF) Pitch (mm) Size (mm x mm) Qty50 4.7 5 5 x 11 150 10 5 5 x 11 150 22 5 5 x 11 250 33 5 6 x 11 250 47 5 6.3 x 11 2100 47 5 10 x 16 1450 68 7.5 18 x 31.5 116 100 5 5 x 11 225 100 5 6.3 x 11 1250 220 7.5 18 x 30 3450 330 10 30 x 40 210 470 5 8 x 11.5 1100 820 7.5 18 x 40 110 1000 5 10 x 16 225 1000 5 10 x 20 210 3300 5 12.5 x 25 4Hopefully, that's enough information to work off of. Unfortunately, I don't have a schematic for this board.I've spent a lot of time tracking down part numbers for each, favoring Panasonic FRs and Nichicon. I don't know if mixing vendors is frowned upon, but in some cases I found one vendor had much better ESR ratings than the others. In other cases I just couldn't find a suitable part for that vendor. The next problem is some of these parts are difficult to source in such low quantities. In order to get the full set of capacitors, I need to buy from both Arrow and Digikey. I've looked at Arrow, Digikey, Mouser, and Newark and none of them have all the parts available.I'm looking at ~$65 for all the capacitors, once shipping is worked in, with the bulk of the order going to Arrow. It's not the cheapest repair in the world, but if I can extend the life of the TV, I'm happy to do it. I am a little bit worried that I'm replacing parts unnecessarily. Beyond the cost savings (the larger capacitors are a few USD apiece), I don't want to introduce new problems by replacing items I shouldn't. I appreciate any feedback or guidance on the repair.

author: PKTKS
author_rank: Super Contributor
timestamp: March 27, 2021, 01:15:28 pm
content: *SHOULD* be close enough for that..in RAR parts due to limits.. and 7z extensionPaul

author: PKTKS
author_rank: Super Contributor
timestamp: March 27, 2021, 01:16:41 pm
content: p2

author: PKTKS
author_rank: Super Contributor
timestamp: March 27, 2021, 01:17:54 pm
content: p3

author: wraper
author_rank: Unknown
timestamp: March 27, 2021, 01:27:14 pm
content: Those bulged capacitors likely are Samwha WB which are bad series. If you replace all of WB, you can probably leave the rest as is. Note that WB is ultra low ESR series. You don't need to replace high voltage capacitors, usually they last much longer.

author: drussell
author_rank: Super Contributor
timestamp: March 27, 2021, 01:42:56 pm
content: Quote from: nirvdrum on March 26, 2021, 04:04:15 amGenerally the only ones that are really stressed in any way are the ones handling large pulses of relatively high current like in the outputs of switching supplies and regulators. I would only replace any of the ones that are in those positions, you can probably spot some any of those areas just looking for switching transformers or power inductors. These will be the ones that are low-ESR, high-ripple-capable types because they need those characteristics. You can look up the datasheets for the couple different series that are likely in there and just replace the ones that are those series.What was/is the symptoms / problems with the TV? Did it simply stop turning on? Was it becoming problematic before and then just failed? There is a good chance that your issues are caused only by the capacitors that are obviously dead. Probably the "easiest" and certainly least expensive would be to just replace the obviously toasted ones and see how the set works unless you have reason to suspect that more are failing / likely to fail.This brings you back to either being the same part type / series as the ones that failed and/or used in similar service in the circuitry and trying to decide if they're likely to go "bad".

author: RayRay
author_rank: Frequent Contributor
timestamp: March 27, 2021, 01:59:17 pm
content: If you wanna save up, I'd recommend you order the caps from lcsc.com (they have a great selection of rubycon/nichicon/panasonic /united chemi-con ones) at reasonable prices, and without having to purchase em in bulk (they also have multiple shipping options available, so you could save up there too, if you don't mind waiting a bit longer for em to arrive). As for your questions, things aren't always as they seem (and a cap be bad even if it looks okay physically) so if you can't test the capacitance & esr, it'd be best you'd have em all replaced to be on the safe side (with low esr ones of course) and no, there's absolutely no problem with mixing capacitors of different brands on the same circuit board. And remember, the key rule with capacitor replacement is having the same uF rating with the voltage being either equal or higher, so for example, for the 1000 uF ones, you could just have em replaced with 25v 1000uF (no need to purchasse 10v and 25v in separate!) Set the capacitors aside, I'd suggest you also test out the rectifier diodes (in both diode & ohms mode on your meter) as explained here:https://www.eevblog.com/forum/repair/bosch-al1820cv-blowing-capacitors/msg3521746/#msg3521746The diode testing function alone isn't compeltely reliable. Also, here's the service manual for that particular TV:https://www.manualslib.com/manual/1200684/Lg-50pg30.html

author: perieanuo
author_rank: Frequent Contributor
timestamp: March 27, 2021, 04:22:25 pm
content: normally somebody ( a pro) won't replace 100% of electrolytics present on pcb, only those supposed to die (near heat source, big challenge - riple for example)but you can replace all if you want, personally i replace only the 'suspects of service', don't realise if it make sense in english

author: RayRay
author_rank: Frequent Contributor
timestamp: March 27, 2021, 04:56:39 pm
content: Quote from: perieanuo on March 27, 2021, 04:22:25 pmI disagree with what you're saying here. A pro wouldn't do repair work based on speculation (he'd test the capacitance & esr of all of em, outside the circuit, before deciding what needs to be replaced) but given the fact the OP doesn't have proper testing gear, I think he'd be best replacing all of em and not leaving anything to chance.

author: wraper
author_rank: Unknown
timestamp: March 27, 2021, 05:09:32 pm
content: Quote from: RayRay on March 27, 2021, 04:56:39 pmPro won't do such time wasting exercise. No pro values their time so low to spend it on desoldering every capacitor just to put them back later. Not to say measuring ESR in circuit is enough in most cases.

author: RayRay
author_rank: Frequent Contributor
timestamp: March 27, 2021, 05:30:44 pm
content: Quote from: wraper on March 27, 2021, 05:09:32 pmWe aren't talking about an excessively high number of capacitors here. Desoldering (with the right soldering station, technique and experience) isn't difficult, and yes, the ESR can be measured in circuit too (depending on the meter). Capacitance in some cases as well (if the cap isn't connected in series to another) and sometimes, desoldering one leg would suffice for taking a measurement. I still stand by my words, you can disagree if you wish, but my opinion is, when reparing, leave nothing to chance, and test everything accordingly. And again, given the OP doesn't have the proper testing gear, it is my opinion that he'd be best replacing all of the caps.

author: wraper
author_rank: Unknown
timestamp: March 27, 2021, 05:56:26 pm
content: Quote from: RayRay on March 27, 2021, 05:30:44 pm"Only" 28 capacitors. Who will pay for the time spent? What about mechanical and thermal stress on the seals? If you take the effort of desoldering them, you just replace all of them. Also usually you cannot desolder one leg of electrolytic capacitor. And why don't you check every other part outside of the circuit and then assemble everything back? You don't want to take any chances after all.

author: RayRay
author_rank: Frequent Contributor
timestamp: March 27, 2021, 06:08:49 pm
content: Quote from: wraper on March 27, 2021, 05:56:26 pmI think you're taking this a bit too personal. Overall, the OP was given two different approaches, and it's up to him which one he prefers to go with (and it's his time, not yours!) From one hand, it's possible that replacing only the bad ones & the higher capacitance ones alone would suffice, from the other, it's a gamble, which may not do the trick. And yes, you can desolder one leg of a capacitor just fine (with a wick/pump, leaving it in the joint, but not connected).

author: nirvdrum
author_rank: Contributor
timestamp: March 28, 2021, 05:36:37 am
content: Quote from: drussell on March 27, 2021, 01:42:56 pmWe had a brownout and afterwards the TV turned itself on and went into a power cycle loop. I had to disconnect the power cord to get it to stop. Fortunately, the TV doesn't remember power state on AC loss or anything like that, so if I plug it in, it remains off until I press the power button. Xut pressing the power button puts it into a power cycle loop: it turns on, shuts off about a second later, then turns itself back on, then off again, until I remove the power cord again.When working before, the TV always took a little while before the screen started displaying something. I can't tell if it's a situation where it was just gradually getting slower over time. I'm curious to see if the capacitor replacement makes the TV turn on any faster. But, I was mostly thinking of replacing more than the obviously bad ones because it's a 12 year old plasma TV, so the caps have certainly had some heat exposure. $8 shipping for four capacitors kinda sucks, so I was trying to cut down on the back-and-forth.Thanks for the other info. I'll read the datasheets for the various Samwha series.

author: nirvdrum
author_rank: Contributor
timestamp: March 28, 2021, 05:47:04 am
content: Quote from: wraper on March 27, 2021, 01:27:14 pmIndeed, they are. There are some other WB caps on the board that don't have visible signs of failing, but I don't have an ESR meter. I'm debating whether to just order one at this point. Some of the caps are oriented in such away that I can't read the series identifier without removing the part. It looks like some are from the RD, PT, and WL series.I'll go read up on the others. Obviously, the manufacturer isn't going to say some of their products are bad, so I appreciate sharing any experience. Likewise, I couldn't tell whether the 2008 manufacturing date was something to consider or not as well, given the problems with capacitors from earlier in that decade.

author: nirvdrum
author_rank: Contributor
timestamp: March 28, 2021, 06:29:41 am
content: Quote from: PKTKS on March 27, 2021, 01:15:28 pmThanks for sharing that. Unfortunately, the schematic labeled "POWER" doesn't appear to match the PSU board I have. Or, I'm reading it wrong (in this case the effect is the same).

author: nirvdrum
author_rank: Contributor
timestamp: March 28, 2021, 06:37:45 am
content: Quote from: RayRay on March 27, 2021, 01:59:17 pmThanks for the recommendation. I had come across that site, but I couldn't determine how trustworthy it is. The last thing I want to do is unwittingly use counterfeit capacitors.

author: gnuarm
author_rank: Super Contributor
timestamp: March 28, 2021, 06:40:26 am
content: Quote from: RayRay on March 27, 2021, 04:56:39 pmThat doesn't make sense to me. Caps are rather inexpensive items. Testing them out of circuit would cost as much as replacing them.

author: RayRay
author_rank: Frequent Contributor
timestamp: March 28, 2021, 02:26:56 pm
content: Quote from: nirvdrum on March 28, 2021, 06:37:45 amYou're very welcome. FYI, LCSC is a very reputable store (that's been around for a long time) and they're definitely trustworhy. I've personally ordered various components from em (incl capacitors) and I can assure you they don't sell counterfeits!Quote from: nirvdrum on March 28, 2021, 05:47:04 amWell, getting one would certainly be useful, but would cost you way more than just replacing the caps, so if anything, I'd say it'd be a good investment for future repairs. Provided you already have a decent capacitance meter (or that functionality in your multimeter, with a decent range) you could get the MESR-100 for around $60. If you don't have any capacitance meter though, it'd prob be best to go with the DE-5000 or Atlas ESR70

author: nirvdrum
author_rank: Contributor
timestamp: March 28, 2021, 04:25:10 pm
content: Quote from: RayRay on March 28, 2021, 02:26:56 pmUp until I started looking into this repair, I didn't even know ESR meters existed. If having one is good, I don't mind investing in equipment. I have a Proster BM4070 LCR meter that I picked up measure capacitance among other things, but it doesn't have ESR functionality. Beyond that, I have a Siglent SDM 3055 bench DMM and an older Radio Shack 22-174B hand-held DMM. I'll take a look at the ESR meters you mentioned.

author: RayRay
author_rank: Frequent Contributor
timestamp: March 28, 2021, 05:41:09 pm
content: Quote from: nirvdrum on March 28, 2021, 04:25:10 pmHaving one is definitely very handy! Anyways, given the fact the capacitance range is a bit low on your LCR, I think it'd be best you'd go with a combo ESR/Cap meter (DE-5000/ESR70) rather than a standalone ESR one.

author: nirvdrum
author_rank: Contributor
timestamp: April 04, 2021, 02:16:53 am
content: Quote from: RayRay on March 28, 2021, 05:41:09 pmI ended up getting the DE-5000. I was able to measure most caps in-circuit. A couple gave odd readings, but I haven't popped them off yet to isolate them. Two of the caps are Samwha PT series, but I can't locate any datasheets for those.I ended up measuring dissipation @ 120Hz and ESR @ 100kHz in-circuit for all the caps (~21°C). Other than the low and ultra low ESR ones, the datasheets didn't have ESR values to compare against. The bad ones are clearly bad. The others all seem to be within spec. I don't have values from a previous point in time, so I can't tell if any others are trending bad. I'm inclined to just replace the four bad ones. Or maybe all the WB ones as that series was indicated as problematic and even Samwha doesn't seem to stock it anymore.Thanks for the help everyone. I need to re-evaluate my replacement options, too. I had initially picked them based on voltage, capacitance, and ESR, but not max. ripple current. Now that I have most of the Samwha datasheets, that's a lot easier to evaluate.

author: wraper
author_rank: Unknown
timestamp: April 04, 2021, 02:19:40 am
content: Quote from: nirvdrum on April 04, 2021, 02:16:53 amThe best way to measure ESR in circuit and ESR for large capacitance in general is setting it into resistance mode at 100kHz frequency.

author: nirvdrum
author_rank: Contributor
timestamp: April 21, 2021, 05:42:28 pm
content: I'm just finally getting around to ordering these capacitors. The ones I really need to replace are the 10V 3300uF ones. The old WBs had a max. ripple current of 2770mA @ 100kHz. Unfortunately, I can't find an FR that matches that spec. The 10V 3300uF 12.5x25mm FR looks like it'd do it with a 3190mA ripple, but I can't find anyone that stocks it. Arrow, Digikey, and Mouser all only have the 12.5 x 20mm with the 2600mA ripple. I can go with an FM series that has a max. ripple current of 3190mA @ 100kHz, but people seem to really like the FRs over the FMs. The FR looks to be more resilient with a much longer lifetime. If it's got a better construction, is that 160mA difference between the ripple rating on the WB and the FR going to make a real world difference? Or would I just be looking at premature failure that way?

author: wraper
author_rank: Unknown
timestamp: April 21, 2021, 06:01:14 pm
content: QuoteThere is nothing wrong with FM, they are certainly better than WB even if they were not flawed. Problem with WB is not ripple current rating but that they had an inherent flaw causing their premature failure. And preferences of those people are lame since there is zero research of even anecdotal evidence behind that.

author: nirvdrum
author_rank: Contributor
timestamp: April 21, 2021, 10:35:46 pm
content: Quote from: wraper on April 21, 2021, 06:01:14 pmThanks for the help. Just for my own edification, would the EEU-FR1A332B be okay to use here with the slightly lower max. ripple current? I'll planning to go with the EEU-FM1A332 anyway, but I'm trying to get a sense for how tight these tolerances typically are. The practical matter at hand is I'm finding different vendors have different min. quantities or some parts just aren't in stock. I'm shopping around, but it's a chore and shipping is going to hurt. If I need to hit all the specs the original parts had, so be it, but if there are rules of thumb or approximations I can use, that'd be good to know too. Thanks again.

author: wraper
author_rank: Unknown
timestamp: April 21, 2021, 10:51:29 pm
content: Quote from: nirvdrum on April 21, 2021, 10:35:46 pmYes, the difference is insignificant. And that ripple current rating is given for longer lifetime than for WB anyway. So those figures are not exactly equal. But I would go for FM of larger size.

author: drussell
author_rank: Super Contributor
timestamp: April 22, 2021, 01:36:07 am
content: You will find that many boards, especially plasmas where there is a need for multiple high-ripple-current caps in parallel, they will often have extra footprints for capacitors so they can populate at will depending on what caps they could get at the time to handle the total load necessity of the zappa zappa zoltch in total...Going from 2.5 to 2.7 amps or something won't matter but if you have the opportunity, uprate it where you can or add another cap or two whenever spaces are there on the PCB...

author: nirvdrum
author_rank: Contributor
timestamp: April 25, 2021, 10:15:38 pm
content: Thanks for the help everyone. I've got an order ready to swap out all the WB series capacitors from Digi-Key. I was thinking of ordering one spare for each cap I'm looking to replace, where each cap's quantity is 1, 2, or 4, depending on specs. Is that sufficient? Is it overkill? I've been searching discussions here and can't find anything regarding expectations and best practices with electrolytic orders. I figured a spare one would cover me in case one tests bad or if I somehow screw up soldering, but I don't have any real experience to back that up.

author: wraper
author_rank: Unknown
timestamp: April 25, 2021, 11:07:32 pm
content: Just replace what you need to replace, no extras needed.