Z5500 no sound

[NoClueInElectronics]

Hello all,

I wash searching google to fix my Z5500 which have no sound (one day I was listening to music and the speakers just stopped working). Many post were in pc related forums and I can tell people there have no clue about pcbs. I also found some youtube videos about repairing subwoofer which replaced capacitor and the system was working (Su'scon 4700 uF 25V 85°C). Now I opened subwoofer and checked pcb thinking I will probably just replace this capacitor which is responsible for control pod (since control pod just posts No digital data). But I found out that there was small capacitor (looks like MLCC) which is connected at positive terminal to big Su'scon 10.000 uF 50V 85°C capacitor, and it was burnt and lifted up. Also there is something burnt in the pcb lines (WA90 and WA91), not sure what that is. Now my question is, do I need to replace both capacitors? And how can I know what rating does this small capacitor have? Or is something else the problem that I have no sound?

Also I have no clue about electronics.

Picture is also attached if that helps.

Thank you in advance for any input.

 

[Nanren888]

There appears to be quite a lot online about moding the Z5500.

There appears to be a schematic at
https://www.head-fi.org/threads/alm...upgrade-for-the-speaker-system.657715/page-10

Not surprisingly, C27 appears to be a power supply capacitor.
WA90 seems to be the -18volt supply and WA91 the positive 18 volt sypply, or perhaps connectors for the same.
While it is possible that these capacitors failed, if they all went at the same time, it might suggest that something in the power supply went AWOL. This could have caused widespread damage. The power supply should be checked as well as looking for other damage.
Also, is there any evidence of the capacitors on the component side bulging or leaking?

 

[WHONOES]

First of all, you should check the mains fuse if you haven't already done so. Then, if you can disconnect the transformer secondary's, check their voltages. It may be easier to remove the ac connections from the bridge rectifier instead.

 

[NoClueInElectronics]

Thank you for your replys.

Nothing else on the pcb looks burnt or deformed. It looks normal.

Main fuse is normal. It is not broken. Transformato secondarys are the the ones with +-26,4V or 14,5V?

It will be harder to help someone that doesn't know much about electronics :/.

 

[Nanren888]

Then, if you can disconnect the transformer secondary's

Transformato secondarys are the the ones with +-26,4V or 14,5V?

Yes, the output, lower voltage side.
Whonoes is suggesting that you test the transformer output without the circuit connected if that can be done.
.
Take care if you are working on anything live. That high voltage side can be hazardous to your health.
Is it is an option, you could consider having it looked at by a local repair guy.

 

[NoClueInElectronics]

The transformer is that big coil in the subwoofer right? So I would need to disconnect black, red, yellow wire from the board and test if it has +26,4V from black to yellow wire and -26,4V from black to red wire?

The only thing I need to watch out is black and white wire that goes to transformer where it is 230V AC?

Where I live it is small country and it is almost impossible to get anything with pcbs fixed. All the repair shops only repair parts like screen or speakers (like parts that you just replace if you told them they don't work). This was the reason that my Z5500 were sitting for some years now.