Logitech Speakerset Repairing - Page 1
Forum section: electronics / repair

author: danger89
author_rank: Contributor
timestamp: October 12, 2015, 03:12:52 pm
content: Hi,My Logitech Speaker Set (just 3 years old) let me down.So, I though let's open this thing and find out what's going wrong inside!After some search I noticed some bright sparks (almost firework) coming out of the bottom of the PCB ahhaa. So I knew enough. I removed the PSU PCB plate.Tada!Conclusion: a capacitor was broken and cracked open. Some glass liquid is dropped out (no idea what this is? But don't eat it I guess). I removed the broken cap and cleaned it. As you can see here:Now, the hard part: it's SMD component. Meaning there is no indication what value is has? Or other specs (250V? ESP?), you just ** don't know....I hope, now you come into the picture. Can you give me some advise or something to help me further? I already bought a LCR Meter (currently shipping). I didn't had one yet.To be complete: it's a Logitech Speaker System Z906:Thanks in advance!Kind regards,Melroy van den BergFull-HD pictures:

author: HighInBC
author_rank: Contributor
timestamp: October 18, 2015, 07:05:47 pm
content: I have encountered burnt SMD capacitors before. I have never heard a good solution to figuring out what they used to be. If anyone knows this wisdom it would be of great general use.

author: Rasz
author_rank: Super Contributor
timestamp: October 19, 2015, 03:53:33 am
content: 1 check those transistors2 power it up with no cap3 caps below transistors appear to be the same, probably ~1uF

author: crispy_tofu
author_rank: Super Contributor
timestamp: October 19, 2015, 04:59:06 am
content: Quote from: HighInBC on October 18, 2015, 07:05:47 pmSame, that would be helpful.Following!

author: alanb
author_rank: Frequent Contributor
timestamp: October 19, 2015, 10:17:55 am
content: Have you checked that there isn't an identical part for the other Chanel. If there is you could remove it and measure the value.

author: danger89
author_rank: Contributor
timestamp: October 19, 2015, 02:09:24 pm
content: Quote from: Rasz on October 19, 2015, 03:53:33 am1. What do I need to check? The value? If they still work? If so, how? I did already a datasheet 'typical (reference) design' look-up without luck.2. And then? Maybe it will cause more damage? So I need to fix that too...3. True, they seems the same. Probably ceramic low ESR caps. I bought a LCR meter (see below), hopefully I can figure out the value asap.Thx!

author: danger89
author_rank: Contributor
timestamp: October 19, 2015, 02:11:55 pm
content: Quote from: alanb on October 19, 2015, 10:17:55 amOn the other channel I only see a diode, no capacitor. As you can see on the picture. I will try to measure one of the caps below the transistors very soon I hope.

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 19, 2015, 02:32:23 pm
content: Quote from: danger89 on October 19, 2015, 02:11:55 pmOther channel? These are clearly diodes (D20 and D2?) and not transistors, so it could as well be part of the power supply.What is the exact problem, it does not power up anymore?Is there a connector on the other side of the PCB on the row of pins? Where is it going to?

author: danger89
author_rank: Contributor
timestamp: October 19, 2015, 03:13:03 pm
content: Quote from: PA0PBZ on October 19, 2015, 02:32:23 pmyes you are right. D20 and D2 are diodes, sorry I was getting confused.The problem is indeed it doesn't powerup anymore, and I heard some sparkling. When I opened the case and connected the speaker again: I saw flames .. it was almost firework! WAUW. But atleast I knew where I needed to look at, the bottom side of the power-circuit PCB board. Then I saw this capacitor was clearly broken.Yes there is a connector for the input voltage (230V) and there are 2 other connectors going to an other separate board. Uhm.. I will take more picturestoday, is that OK? I think that makes is more clear. This second board is probably the amplifier board itself, and not the power-circuit board.Kind regards,Melroy van den Berg

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 19, 2015, 03:17:57 pm
content: Hi Melroy,Yes, a few more pictures would help. I don't think the failure is just the capacitor, it would normally not completely cut the power.Can you measure the 2 diodes to see if they are still acting as a diode? If they seem weird disconnect them from the pcb and measure again.

author: danger89
author_rank: Contributor
timestamp: October 19, 2015, 03:30:35 pm
content: Quote from: PA0PBZ on October 19, 2015, 03:17:57 pmOk no problem. Well, sometimes there was just a bit of power. Within a second the devices goes off again. You needed to press several times the power button over and over again to turn it on for a second or less. But as you can see the capacitor is really really broken (see pictures). What I mean is that is damage can lead to total power failure.I can try to measure the diodes in the eveningThanks for the tip.

author: Rasz
author_rank: Super Contributor
timestamp: October 19, 2015, 06:47:18 pm
content: hah they are diodes not transistors, didnt payu attention :/this cap fried because it shorted, running without a cap wont damage anythingcheck those diodes for shorts (and all the diodes around while you are at it), + power input (where power comes from socket)

author: danger89
author_rank: Contributor
timestamp: October 19, 2015, 07:57:37 pm
content: Quote from: PA0PBZ on October 19, 2015, 03:17:57 pmI uploaded more pictures here for convenience:http://photo.melroy.org/thumbnails.php?album=1ps.'Power Circuit Bottom Side' picture is where the fun is happening.ps.ps. there is also a Download link if you need the original file for some reason.

author: danger89
author_rank: Contributor
timestamp: October 20, 2015, 08:43:04 am
content: Quote from: Rasz on October 19, 2015, 06:47:18 pmI will thanks. I checked around the power input, I didn't saw anything strange. No blow-up caps and no broken fuses what so ever. Bottom left in the main power input:Top ImageAt the bottom of the PCB, the top-left is now the main power input on this image (I flipped the board over):Bottom Image

author: Rasz
author_rank: Super Contributor
timestamp: October 20, 2015, 10:39:09 am
content: 1 did you try turning it on without the cap?2 those 2 thin traces originating near burn area and going all the way to the other side of the board to terminate at the connector are interesting, this small part appears to be market RT1 = smd NTC Thermistor = they knew this part of pcb would be cooking = W T F?

author: danger89
author_rank: Contributor
timestamp: October 20, 2015, 10:49:03 am
content: Quote from: Rasz on October 20, 2015, 10:39:09 am1. I will try that soon, after I measured both diodes (D2 & D20) first.2. Can you circle the place where you find this RT1 component on the picture?

author: Rasz
author_rank: Super Contributor
timestamp: October 20, 2015, 12:42:02 pm
content: Quote from: danger89 on October 20, 2015, 10:49:03 amit is the one marked RT1 on the silkscreen, surely you can see it on actual board if I can see it on your picturebtw clean that burned spot with IPA

author: isopropilick
author_rank: Contributor
timestamp: October 22, 2015, 07:39:31 am
content: I will facilitate the work, my little friend your cap is this (obviously i cut 1 trace to made the capacitor measurement and reconnected to make the voltage measurement): 2.2uf at 100v

author: danger89
author_rank: Contributor
timestamp: October 22, 2015, 08:01:57 pm
content: Quote from: isopropilick on October 22, 2015, 07:39:31 amWAUW!I can't thank you enough isopropilick! I measured the cap below (which kinda looks the same as the original cap). This gives me the following result: 1.73uF (using a cheap meter). Still this is one of the caps which looked similar at the left bottom in the picture and NOT, I repeat NOT, the original.See:Nevertheless, I'm 100% more sure about your measurement, because of the following points:You got a FLUKE multimeterYou are measuring the original / right capacitor, the one that is broken at my side!Maybe you want to send a nice high detailed photo near the capacitor, so I can see how I need to solder it back again --> I mean over here thetop layer PCBalso a burned away.Thanks.==========================Ps.I also measured the diodes near to the broken cap. Diode voltage: 0.365V (and the other-way-around: 'LO' as expected). And 4 MOhm resistant at one way and 'LO' to other-way. Can somebody agree with me, that the diode is atleast still OK?Ps. ps. I'm also interested how you measured the voltage (100V) of the cap? The set-up and multimeter settings.QuoteI ordered IPAthx for the hint, still I don't know how easy it is to clean. It's not flux what you are seeing, but burned capacitor liquid.

author: Rasz
author_rank: Super Contributor
timestamp: October 22, 2015, 09:23:09 pm
content: its mostly carbon buildup saturating solder mask, will be ok once you clean it with alcoholI am guessing isopropilick estimated cap voltage based on working voltage he measureddepending on a type caps can have a HUGE tolerance error (Dave talked about it on one of the recent videos), for fun go to mouser/farnell and look at available parameters for 2uF ceramic cap

author: danger89
author_rank: Contributor
timestamp: October 22, 2015, 09:37:52 pm
content: Quote from: Rasz on October 22, 2015, 09:23:09 pmYou have a vid link?Yes, I already checked Farnell. I need to measure the case of the capacitor (size):Sorry it's Dutch

author: isopropilick
author_rank: Contributor
timestamp: October 22, 2015, 11:52:39 pm
content: So yo need more specs? i can provide all what you need (tomorrow when arrive at home)... only request

author: danger89
author_rank: Contributor
timestamp: October 23, 2015, 11:42:36 am
content: Quote from: isopropilick on October 22, 2015, 11:52:39 pmAll? WAUW!Well I think only the size (L"xW") of the casing. Maybe tolerance? The most important details so I can order the correct one.And again, I really would like to knowHOWyou did the voltage measurement. So I can do the same in the future for other peoples to help themEDIT:Ps. I also read about the microphonic behavior of ceramic (layered) capacitors. I need to watch out which cap I will pick. Due to the fact it's a speaker-set, sound waves can enter the cap causing voltage on the pcb routes. And also thinking about the impedance level. I need to find a cap which works on the right frequency to have the best amount of impedance (I'm not talking about ESR only).

author: Rasz
author_rank: Super Contributor
timestamp: October 23, 2015, 11:56:33 am
content: I meant tolerance rangesin general you dont need to stress to much about cap values, its all ballpark anyway (unless radio circuits or fast digital transmission lines)

author: danger89
author_rank: Contributor
timestamp: October 23, 2015, 03:21:55 pm
content: Quote from: Rasz on October 23, 2015, 11:56:33 amIs class 2 ceramic capacitor ok?

author: isopropilick
author_rank: Contributor
timestamp: October 26, 2015, 09:28:41 pm
content: Sorry for the delay ... The work does not forgive, my capacitor is a standard size 8050

author: danger89
author_rank: Contributor
timestamp: October 28, 2015, 12:04:20 pm
content: I already order the following cap (Quantity: 10):http://www2.mouser.com/Search/ProductDetail.aspx?R=C1210C225K1RACvirtualkey64600000virtualkey80-C1210C225K1RACKemet SMD Capacitor -2,2uF, X7R, 100V1210 case size (0,12" x 0,10" / 3,2 mm x 2,5 mm). I think this capacitor will fit, I used my Mitutoyo absolute digital Caliper to measure it.Let's hope this is the good cap!

author: danger89
author_rank: Contributor
timestamp: October 28, 2015, 01:03:59 pm
content: They are delivered!Yes!

author: isopropilick
author_rank: Contributor
timestamp: October 29, 2015, 02:37:20 am
content: keep it up and repair it, tell us the result.

author: Semih
author_rank: Newbie
timestamp: January 23, 2020, 07:56:06 am
content: Hello my friend. Please tell me the codes of Logitech Z906 amp power supply D20 and D2 diodes. Please

author: senso
author_rank: Frequent Contributor
timestamp: January 23, 2020, 11:06:00 am
content: They should be marked on the other side.

author: Semih
author_rank: Newbie
timestamp: January 23, 2020, 07:03:09 pm
content: Thank you. Find. D20 and D2 diode code RF1501 TF3S

author: Saggi
author_rank: Newbie
timestamp: February 02, 2020, 10:07:50 am
content: Bonjour a tousJe vais revenir sur un sujet qui date de fort longtemps mais toujours d’actualité car cette ensemble le Z906 est toujours en venteMa question est quel(s) composant(s) serait t'il la source du flambage de ce condensateur ?Pour info quand le condensateur a cramé, le caisson n 'était pas en fonction juste en veilleSi quelqu'un a une idée elle serait la bien venueMerci par avance

author: Chris56000
author_rank: Frequent Contributor
timestamp: February 02, 2020, 12:07:50 pm
content: Hi!These Z906 things keep blowing up with monotous regularity in many assorted places – I'll have to buy a set before too long so I can make a set of decent layout and circuit diagrams – I won a set cheap a year ago but the seller refused to honour the sale!Chris Williams