From the schematic, I can tell C30 is 220pf 1kv, D16 is 1n4148, but what about C58? 3300pf? what is the voltage?

I noticed that some film caps have a VDC or VAC or just V rating for voltage.
Do this ratings play a role for coupling capacitors? (2.2 uf 50V caps on Edifier M3300 changing to film caps)

hi , at first my s750 just wont turn on and i fix them after that i got 2 cap exploded !
i change them and right now its working as power supply !
but all of my speakers have a low sound and distorted sound i don't know where is the problem exactly,
so i just ask for it if anyone have this problem and know which part of amp make this problem
just tell me and i will find a way to fix it tnx , i keep looking forward to found a way to fix the problem .
if any photo needed i can bring the photos just ask me .

For most of these switching type power supply circuits, especially close to any choke or transformer (such as those used as part of snubber network), the voltage rating of the capacitor should be around at least 1kV (usually to account for any forward and/or back EMF which has usually higher voltage than the supply rail). For that C58, just try using one 3.3nF capacitor with 1kVDC rating (although it looks to be main part of an oscillator startup/feedback loop)...

Hardly matters here anyway as even the audio signal is very low (typically under 2VRMS) and well below 50V peak level (of course not surpassing the voltage of the power supply). The bias voltage held at these capacitors is about half the voltage of the supply rails which is pretty low (again, much lower than 50V)...

First, check what was the voltage output at the main power section (for the power amplifier section). Did you change all the capacitors as shown here? Also check for faulty components, especially that fusible link (zero Ohm resistor) at the main power section...

Got it!

Hi Lex and others posting in this thread! I just wanted to say Thank you! to all of you for making information about this sound system available as it helped tremendously when fixing my set of S750. I would probably never dared to open it, if it was not for this thread that give me all information i needed about the components and other stuff. I am not an expert in this field so apologies if i am going to be asking very basic stuff that anyone should know. I already replaced all the capacitors that was recommended in this thread but i need to replace one resistor that has died but i can't really read the colors down and all the measuring does give me not really clear idea of what resistance he is. i am going to attach an image or the picture that was posted above with my resistor marked. Thanks again for all your help.

Impressive informative guide and log!!!

Hi Lex, all,

Thanks for amazing tutorial. I fixed my s750. This is awesome.

I have replaced all capacitors with panasonic ones. I wonder if there is something wrong or it's normal behavior but the "L" type cooler on the power board (the one near big capacitors) is extremely hot even when i listen the music on low volume. So i added another massive cooler (marked with red arrow) to it and seems a lot better now but still hot. I quess that's why they used 105 degrees capacitors



I had the same issue like Galeak with immediate power of after a power on so i ordered those DB3 for replacement. So hopefully it will help.


Anyways after the replacement of all capacitors the green light was ok but the red light on the remote was death. I searched a little bit and found this


THE PROBLEM WITH THE ?CONTROL POD IF NO WORK, ONLY OPEN USING SCREWDRIVERS
LOOK ONE MICROCHIP ?M34502E4FP?, MAIBE CPU IT IS IN RESET STATE. THE ONLY THING YOU HAVE TO DO IS GET A SOURCE WITH 5 VOLTS DC AND PUT THE NEGATIVE LINE IN THE PIN 2 COUNTING SINCE MARK AS NUMBER AND THE POSITIVE LINE (+) ?IN THE PIN 6 IT IS THE RESET, IF NO ON RED LIGHTS IN THE CONTROL POD PUT THE POSITIVE LINE IN THE 7 PIN THIS PIN IS P2Ain THATS SUPPLY 5V DC TO DE STAND BY BUTTON MANUALLY AND RESET DE POD.
NOW RETIRE THE SOURCE OF 5V OF THE PINS AND THE POD IS WORKING NORMALLY. BE CAREFULL PUTING LINES (+) AND (-) ON THE PINS OF THE MICRO THAT NO JUMP WITH ANOTHER PINS.
HOPE THAT SOLVE THE PROBLEMS.

And this solved my problem (i did both steps with pin 6 and 7). Hope it will help to someone as well.

Cheers

Hi,

its a 22 Ohms 1% for sure and 2W if i am right.

Its 22 Ohms. That resistor is part of a RC snubber network around the recitfiers. I would recommend Google "resistor color code" to find references to resistor values, as well as online resistor color code calculators.

Well, a fan mod would do better to cool down the components though would be more work than just attaching an extra heatsink. I've had another one repaired not long ago. Not as pretty as the first few shown here (due to very stubborn degraded glue)..

Have not yet encountered such problematic control pods, though the usual problems I've encountered is the glitchy standby button (which causes quick on-then-off sometimes) due to worn microswitch inside. The other one, was the stuck volume button caused by misaligned plastic contact internally (can be fixed easily). As for the problem described above, thanks, will look into it when/if I've encountered one of these...

You are clearly a legend and have a lot of knowledge. I also have issues, but would like to hear you live in the UK, so I can pay you to fix my unit!

Here is hoping?!

Unfortunately I'm not living in the U.K. You may try finding someone with electronics repair experience (ie. good with soldering jobs) to help you from your own country at Badcaps...

This post has been edited by lex: Jun 20 2014, 08:12 PM

shame shame!

It can handle the soldering, but I feel out of my depth working out what is wrong i.e. on a visual inspection all looks good (although maybe one questionable diode).

So what happened? Firstly I had that blinking green light issue, where there are enough internet posts saying use a hairdryer to heat it up (which is what I did). Afterwards when turned on the small box power (after a steady green light of 24 hrs or so), there was a pop and now the sound is all distorted/crackly. I am not sure how to diagnose or on what board the problem would be.

If you have ideas, I can test and also post photos, but where to start.

thanks in advance.

As mentioned in this thread, first steps would be to replace those capacitors and clean up all the degraded glue (including those on the other boards besides the power supply one). Sometimes bad capacitors do not necessarily bulge/bloat. They can be also be leaking from the bottom, and/or simply became "dried" without any apparent signs. As for other failed and/or faulty components, then you have to look/observe carefully and may require some tools (such as a multimeter, plus some knowledge on diagnosing/checking for failed/faulty components). For some components, you may need to pull it out to check (ie. cannot be checked in circuit itself)..

That hot air treatment is not recommended at all, and will eventually kill the subwoofer (which is what happened to the original person who posted that "quick fix", his subwoofer finally went kaput). That only works if there are dying/failing capacitors on the power supply. For your information, when capacitors start failing their capacitance is becoming reduced. Heating up electrolytic capacitors will increase its capacitance, thus "restores" some capacitance to allow the power circuits to continue to function. However in the long run, heating up those capacitors will cause the electrolytes inside to boil and degrade, thus finally goes bad and the subwoofer stops working altogether. Also heating up the boards inside the subwoofer dries up and evaporates the conductive chemicals from the degraded glue. This restores normal circuit functions. However as the degraded glue continue to decay and breakdown, more conductive chemicals are produced and causes circuit confusion (due to creation of "phantom circuits"). Using that hot air heating it up only temporarily restores some circuit functions (until the next round). Please note that direct heating can also damage (and degrade) other components as well...

Some photos may help. What is your level of electronics knowledge? In particular, checking for failed/faulty components?

This post has been edited by lex: Jun 23 2014, 02:10 AM

Hello! I from Ukraine, sorry for my English. I have broken Creative GigaWorks S750 7.1 speaker system. I need your help. I followed for your advise and ordered complete set of capacitors but I found some diodes broken. Can You prompt me technical descriptions and analogues to these diodes: D6, D7, D8, D22, D23, D24 и D25. In the schematic (circuit) diagram for power board I found only D8 - 1n4148, and on other the detailed information is not present. Similarly discovered that at a few resistors resistance below set approximately on 40%: R19, R21, R22, R10, R33, R31. I found out the set resistance, but I would like to know, on what yet to pay attention at their replacement (firm-producer, tension).
Thank you for your useful advices. I wait an answer.

woah didn't expect someone from Ukraine to register just for this speaker. sifu lex need to entertain already

Both D6 and D7 are DIACS. The part number is "BR100/03" and you should be able to find it on most online stores. D22, D23, D24 and D25 are actually a 15V zener diode. Can just choose any available 15V zener diode (and preferably with higher wattage), for example "1N4744A"...

Resistors should not be 40% off (that's too much). The most I would tolerate would be 10% off, and the most recommended tolerance is 5% or lower. Thus do check those resistors again. Anyway some of those resistors mentioned are simply 0R (zero Ohm) links such as R31 and R10 thus your measurement could be off due to the error offset on your meter. Thus do check the error offset of your meter, as it could have caused incorrect readings. As for properly measuring the resistors, you have to remove them off the board first otherwise surrounding connected components (including other resistors) could affect the measurement...

They (Creative Labs) no longer make beasts like these anymore. This GigaWorks S750 subwoofer is capable of reproducing frequencies below 35Hz or below 40Hz (the lowest frequency which most run-of-the-mill subwoofers are capable of), as mentioned in its specifications a very low 25Hz...

This post has been edited by lex: Jun 25 2014, 02:50 PM

see why i wanted to restore it so badly

Thanks for your detailed answer. Resistors really showed other indicators after their removal. But I will buy a new one resistor, as when trying to solder it into, he slipped out of the tweezers and lost . I would also like to clarify: a diode D12 – is same 1N4004?

The run-of-the-mill 1N4004 is just a normal/standard diode thus not suitable. That D12 is right after the transformer and this is a switching type power supply, thus you have to use either a schottky diode or a fast recovery diode. In other words, not the same...

This post has been edited by lex: Jun 27 2014, 08:44 PM