Logitech Z506 demise and disassembly

Back in varsity I had a set of 2.1 channel Logitech speakers. They were great, simple and provided good sound. Alas one day they stopped working, never found out why, even after taking it apart (one had to saw open the wooden sub box) and getting several friends and family members to analyse it. In any case, I ended up purchasing a Logitech Z506 5.1ch set to replace them.

And they’ve done me well. Until recently. I’ve had them for about 3 years; I would have expected a longer life but I fear the recent spate of load shedding (and related grid instability) might have given them a knock (oddly I think it’s what happened to my last set too).

Anyway, they stopped working unexpectedly, so logically I took them apart. You can see the process below. It’s quite nicely put together, but also not with the intent of it being taken apart again later.

In any case I looked around a bit and saw that what I still believe is a fuse was not letting any current through (marked T3.15A250V). So, lacking a replacement fuse, I shorted the fuse and thought I’d fixed the problem, alas I fear there was another reason why the fuse had gone as I plugged the power back in.

Cue loud bang, my lights going out and enough flames to give me a fright. 10 o’clock at night, I made my way to my tripboard and reset the plugs, unfortunately I had also managed to trip the switch in my landlord’s house. Fortunately they were still awake and didn’t ask too many questions as I asked if I could check their tripboard quickly.

So I’m once again in the market for new speakers (edit, managed to revive them, see below), but for others who might have more luck than me, here are instructions to disassemble.

Unscrew the 10 screws on the backpanel. Unscrew the 4 screws mounting the speaker to the bottom of the box. Pull the speaker out. You will notice bendy wire clips stapled to the case holding cables in place, loosen these as required.

Undo screws on back and bottom of speaker

Undo screws on back and bottom of speaker

If you have small hands you can unplug the speaker, but otherwise rest it on top. The backpanel slides out, but there is a bit of double-sided tape holding it in place at the back under the panel. You can release this by pulling the PC-Board away from the side of the box. You can then pull the backpanel and PCB out. This will let you unplug the two plugs on the power supply.

Plugs to unscrew and mounting points

Plugs to unscrew and mounting points

With the main board out, you can loosen the two screws holding the PSU in place and slide it out.

partsSimple as that, above you can see where the fuse I shorted was, and also a bit of the transformer which I think I burnt out. Oops :(

A bit of searching led me to believe that I could fit a replacement power supply and all would be alright. I had a spare laptop power supply (90W, 19V) lying around, and I wired this up. So far it has been running like that for several months.

It is also possible to buy direct replacement boards, for example here.

112 thoughts on “Logitech Z506 demise and disassembly

  1. Hello Gareth,
    You seem to have much more knowledge than me in this type of domain so I’ll take a chance and ask you my question. I end up with all part of that same speaker set Z506 but without the right speaker wich include the on/off button. My intention is really only to use it as a second sub so I dont mind about the headphone feature and the bass volume seems to be on the sub itself. So my assle here is that all I need is a On/Off trigger. Is there any way I can do something for that ? soldering an external switch or something ? Any helps would be appreciate. (And if you have any idea of wich part/term I should requierd at my local shop it would be even better ).
    Thank you

    • Hey Yannick, I’m afraid I don’t have this sound system any more, so I can’t check the details.
      However, on the back of the sub you have a connector that is supposed to go to the Front right speaker. It looks like an old serial DB9 plug.
      Most likely connecting two of those pins will cause the power to turn on, but I don’t know which two.
      You’d either need someone with the front right speaker to figure this out, or you might be able to figure it out if you disassemble the subwoofer and have some basic electronics understanding.
      Good luck!

  2. my logitech z506, subwoofer volume Button not working so I removed from board, now subwoofer sometimes works n sometimes work, mostly not work

  3. Hi Gareth, don´t know if its a bit late to ask something on this thread. I’ve had the same problem with the blow fuse andd tried the same solution as you guys, and plugged an old laptop power supply (19V -130W – 6.3a ) and it started working perfectly agin, but after 10 minutes the sound starts to cut nd suddenly stops completely (but the system stays on). I disconnect it, and after waiting a few minutes it works again and then the same thing happens, any idea what it could be ?

    • Hey Mateo, sorry, I can’t think of a specific reason that would happen.
      With the system powered on, you might want to measure the voltage going to speakers and ensure it is getting the full 19V. Also confirm the polarity of the connection?
      How did you connect the power supply?

      • I connected the positive and negative cable (after checking polarity) directly to the AC input of the board. It’s really strange, I was using the RCA stereo input and know that I switched to one of the 3.5mm stereo ones it seems to be working fine but for some reason I can’t comprehend the front left speaker (one with on/off switch) won’t produce any sound, but the switch and volume control work fine. Any ideas? My only guess is that some of the contacts of the audio input jacks might be corroded (I got the system for free on ebay so I have no idea on what conditions it was stored).

        • That is very weird behaviour, but glad that it’s mostly working.
          You could try open up the speaker, and check for continuity between the speaker and it’s plug. It’s possible if it’s old that one of the internal contacts might have been damaged. But the fact that the 3.5mm stereo input is working, but the RCA stereo input stops working after a while might be indicative of a bigger problem. Hard to say.

  4. I tried removing the all power supply and replace it with a power voltage adapter (with wich o can chose the power).
    So the sound is coming but not I don’t hear all the frequencies, even if every single speaker is working. They just don’t give good sound

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