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**mariushm** · 12-24-2011, 08:20 AM

Re: Gigaworks S750 replacement caps?

replace all four...

keep the uF value the same, voltage can go up.

But it's unlikely these cause issues with the audio channels.

**manywelps** · 12-24-2011, 02:12 PM

**mariushm** · 12-24-2011, 03:13 PM

Re: Gigaworks S750 replacement caps?

http://i.imgur.com/jCxE1h.jpg

^^ looks like vibrations opened up/loosened the screws... screw them tight. The IC on the other side may overheat if they're not screwed tight to the heatsink and cause that crackling noise.

That white yellowish stuff is supposed to keep components on the board when they're soldered. Sometimes when it turns yellow and it warms up, it becomes conductive, so that yellow crap may cause some shorts after some time of operation. I'd remove it with a bit of attention not to pull anything from the board...

Otherwise, I would maybe resolder the input wires from the computer and the wires going to the speaker jacks - could be some solder crack there causing interruptions.

The caps otherwise *look* ok but at least the blue ones are Capxon, which is not a particularly reliable brand... in addition they're also only 85c as far as i saw.
So yeah, I'd consider replacing them but this really is optional, as they may be fine - without specialized equipment to test them (esr meter) you can't tell if they're bad or not with high confidence.

**manywelps** · 12-24-2011, 03:16 PM

Re: Gigaworks S750 replacement caps?

Thanks.

Originally posted by mariushm View Post

Otherwise, I would maybe resolder the input wires from the computer and the wires going to the speaker jacks - could be some solder crack there causing interruptions.

Would this occur with no vibrations whatsoever?

**mariushm** · 12-26-2011, 03:37 AM

Re: Gigaworks S750 replacement caps?

manywelps, sorry for not replying faster... I usually like to write longer posts but now I'm not at my usual location (visiting my parents for Christmas) where they have slower computer and it's not a pleasure to type on this keyboard - the layout is totally different.

The first problem you have imho is those loosened screws - I'm not sure what part those chips are part of but if they're not properly heatsinked, they could cause lots of problems.
If they're part of the power supply, the output to the amplifier may be unstable, could get lots of ripple or less voltage than needed, something which the amplifier chips may hate.
They may be part of the amplifier - the system could use one or two chips for each channel and it could be that a chip used for that channel overheats and you hear crackling.

You'll have to replace those 4 large capacitors - those act like a buffer for energy for the power supply - if they break down more the whole thing may turn itself off if you raise the volume, or something like that.

Looking at the boards I see several chips that show poor soldering, see for example this picture: http://i.imgur.com/KV1vL.jpg

See those two rectangular chips with 10 pins on both sides? Look at their pins and how they're soldered - a proper soldering shouldn't let you see a hole there - the pins are just partially soldered and the solder was probably not applied properly as it didn't fill the whole hole.
On a proper soldering, the solder should basically go up the pins of the chips and fill the holes completely.
With this in mind, it wouldn't surprise me that some wires are not soldered very well, that's why I recommended that you resolder those connections just in case.

The actual amplifier chips (or a part of them) are the ones in this picture: http://i.imgur.com/c8Pl0.jpg

I can't tell from the pictures if they're in bridge mode (pair working as one) or not but it shouldn't matter. They also could be just for the subwoofer, as that's generally the high wattage one in the system, the rest of the speakers are a handful of watts each in general.

**manywelps** · 12-26-2011, 06:49 PM

Re: Gigaworks S750 replacement caps?

Update:

In the meantime, I replaced the sound card in the computer, the wires, and the speaker system with an older one.

AND IT STILL HAPPENS. WHAT THE FUCK.

Edit: I'm still going to replace the power caps on the S750, what brand of 470uf 200v caps do you guys recommend?

**momaka** · 12-27-2011, 09:21 PM

Re: Gigaworks S750 replacement caps?

Originally posted by manywelps View Post

Edit: I'm still going to replace the power caps on the S750, what brand of 470uf 200v caps do you guys recommend?

Panasonic, Chemicon, Nichicon, Rubycon.

What's the diameter (in mm) of your caps?
If 25 mm will fit, get some of these:
http://search.digikey.com/us/en/prod...1614-ND/483212
If 25 mm won't fit, there's 22 mm:
http://search.digikey.com/us/en/prod...6821-ND/131703

I suggest you replace not just the 2 bulging CapXon 200v 470uF caps, but all 4. If there are any other larger caps (470uF and over) of inferior brands rated for 85C, it might be worthwhile to replace those with 105C replacements as well - might as well since you have to pay shipping for the other caps anyways.

**mariushm** · 12-27-2011, 10:12 PM

Re: Gigaworks S750 replacement caps?

I forgot about this.

If you still hear weird sounds in one of your speakers even when you change them or the amplifier, it could be something caused by the computer or some other electronics near that speaker.

Basically the cables coming from the pc to the amplifier or the cable from the amplifier to the speaker is not shielded, so you may get electric interference from...for example.. radios, the computer's power supply, video card etc...

Think of what you changed to your room when the speakers started to make sounds...

**manywelps** · 12-28-2011, 04:10 PM

Re: Gigaworks S750 replacement caps?

solved. I was using the 7.1 analog 3.5mm (x4) cables that came with the speakers. Apparently the front right line in one of the cables broke.

The bottom PCI slot in my motherboard is apparently loose, tapping on that causes a similar, but not identical symptom in the front right speaker.

That's why I heard the cracking with headphones straight into the card.

I:

1)Moved the PCI soundcard up one slot.

2)Used the alternate set of 3.5mm cables.

Basically I got confused because 2 problems arose simultaneously.

Originally posted by momaka View Post

Panasonic, Chemicon, Nichicon, Rubycon.

What's the diameter (in mm) of your caps?
If 25 mm will fit, get some of these:
http://search.digikey.com/us/en/prod...1614-ND/483212
If 25 mm won't fit, there's 22 mm:
http://search.digikey.com/us/en/prod...6821-ND/131703

I suggest you replace not just the 2 bulging CapXon 200v 470uF caps, but all 4. If there are any other larger caps (470uF and over) of inferior brands rated for 85C, it might be worthwhile to replace those with 105C replacements as well - might as well since you have to pay shipping for the other caps anyways.

I think I can fit the 25mms, they might actually be easier due to height. I may have to clean that gunk off the board though. Also I should look for nearby components.

It looks like the 25mm is better (ripple/ESR), is that correct?

**mariushm** · 12-28-2011, 05:22 PM

Re: Gigaworks S750 replacement caps?

Get what you're sure it fits. With those capacitors, the ripple and ESR don't matter that much, but of course the price difference is so small you shouldn't get the lowest performance caps...

Here's another suggestion:

http://search.digikey.com/us/en/prod...2016-ND/589757

If they're smaller than 22mm, maybe you could install just two capacitors instead of four, of higher capacity (double) - it depends how the capacitors are connected... if they're just 4 in parallel or they're two pairs, so that they'd be doubling the voltage (200x2 = 400v, enough for Europe's 230v, ~360v rectified )

**manywelps** · 12-29-2011, 10:49 PM

Re: Gigaworks S750 replacement caps?

Originally posted by mariushm View Post

Get what you're sure it fits. With those capacitors, the ripple and ESR don't matter that much, but of course the price difference is so small you shouldn't get the lowest performance caps...

Here's another suggestion:

http://search.digikey.com/us/en/prod...2016-ND/589757

If they're smaller than 22mm, maybe you could install just two capacitors instead of four, of higher capacity (double) - it depends how the capacitors are connected... if they're just 4 in parallel or they're two pairs, so that they'd be doubling the voltage (200x2 = 400v, enough for Europe's 230v, ~360v rectified )

TY

I'm in US, no idea why they're using 4x 250V caps in parallel(I think)

**dlduscg** · 01-19-2015, 09:56 PM

Re: Gigaworks S750 replacement caps?

Hi, I wud like to join this discussion about the s750 and try and get sum insight into my particular problem. Started with no power (no green light). Cleaned all degraded glue and replaced all recommended caps altho only found one 470 cap leaking, checked all suspect components, cleaned boards and reinstalled without input and without external spkrs. Applied power and green light came on and everything appeared normal. When I powered on the audio control unit I got a high pitch (varying intensity) sound coming from the sub. Changing the volume level on the control unit has no effect on the sound. Checked for ground loop without results. Suspect the filter cap on the audio board which I did not replace (1000 mfd 100v), but have not replaced it yet. Is there something I missed?

Well, I've check and rechecked everything I've done and have determined, thru the process of elimination, that the problem is in the audio board which feeds the center/woofer and side speakers; the other outputs work fine, but when I disconnect the ribbon connector from the board, the high pitch sound is no more. I am considering replacing all of the caps on this board. Does anyone have any suggestions before I start replacing caps, like is there something I missed?

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Gigaworks S750 replacement caps?

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