Logitech X-220 Cap List

[mockingbird]

Here are the list of caps on the board inside the subwoofer:

1) 25V 4700uF 16mm x 31.5mm Samxon "GS"
2) 16V 470uF 8mm x 12mm Samxon "GR"
3) 16V 470uF 8mm x 12mm Samxon "GR"
4) 16V 470uF 8mm x 12mm Samxon "GR"
5) 25V 100uF 6mm x 12.5mm Samxon "GR"
6) 25V 10uF 5mm x 11.5mm Samxon "GR"
7) 25V 10uF 5mm x 11.5mm Samxon "GR"
8) 10V 100uF 5mm x 7mm Samxon "SS"
9) 16V 10uF 4mm x 7mm Samxon "SS"
10) 50V 0.47uF 4mm x 7mm Samxon "SS"



My question is like this:

In PSUs, the rule is that the quality of the main filter caps is not as important as the secondary filter caps because of the low frequency. The way I understand it, in a computer PSU, the wall AC voltage goes through the bridge rectifier and then to the main caps, and then to the high frequency switching transistors.

But this sub uses a transformer first to step down the AC to what I imagine is 16V or so, goes through the foru-diode rectification, then goes unregulated through the main filter cap (And that's why it must be over 16V), and only then does it pass through the switching transistor. So this is effectively a wall wart adapter.

So, previously I have found many bad caps in AC to DC wall warts. Is there high frequency ripple going to these caps, and do you need a high quality part in these applications, unlike in computer PSUs?

Also, I am looking to purchase the main big 25V 4700uF filter cap, but I don't want to spend that much just for one single cap at Digikey... Does anyone have any cap of this type lying around that they would care to sell?

I can probably squeeze an 18mm cap in there, but the height is very important since the board won't slide back in unless the main cap clears it. I think 35mm is the absolute maximum.

[mockingbird]

Re: Logitech X-220 Cap List

I managed to purchase 6 pieces of Panasonic FC 25V 4700uF. They're 18mm x 35.5mm, wider and taller than the originals, so I might have to bend the leads and mount it at an angle. So far I've already replaced everything else. I might take a picture of the PCB when it's completed.

The whole project started in the firstp lace because my motherboard's audio failed... It only occured to me to test the motherboard audio with a pair of headphones after I'd already opened the speakers up.

Another lesson I learned is to replace those green Lelon caps on the motherboard audio circuits while re-capping the board. I did everything but them because I didn't think they'd fail. But I replaced all the audio capacitors (so now every electrolytic on the board is high quality), and it worked great immediately after.

Oh well... These speakers were due for a re-cap for years now. Yes, they work worked with the original caps, but there were a few problems like the power LED on the front right speaker not coming on. Hopefully, this will lengthen their life for the next 10 years. I also have an Altec Lansing ACS56 I bought many many years ago that I need to repair.

[mockingbird]

Re: Logitech X-220 Cap List

I received the used caps today.





Take it from me folks: There's absolutely nothing wrong with buying used caps, as long as they were good quality to begin with.

The 18mm diameter wasn't a problem at all, but it would not fit through the slot, so I used a chisel and hammer to notch out a bit of the wood.

It's not a big deal at all because firstly, this is some really soft cardboard-like wood and secondly, because the plastic cover conceals the notch when everything is screwed back in place.

After putting everything back together, the speakers work brilliantly. They weren't the problem to begin with, but I'm glad I re-capped them because they needed to be re-capped anyways.