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
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
With the main board out, you can loosen the two screws holding the PSU in place and slide it out.
Simple 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 :(
Update:
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.
I have a set of these and noticed different problems such as a failes psu right control speaker sometimes is fault turn on sometimes sometimes not at all tried different one from a a friend no problems at all broken wires going to left and right front speakers broken 3.5mm wires and bad wiring inside the right front control speaker specifically the ground also some make a low ruble noise from sub on low volumes goes away with a small pop noise when volume is tuned up to at least a quarter sub volume control has no effect
were is the fuse for the z506 ?
Did you look at the article? It’s soldered onto the PSU. It’s right there in the last picture. Even has a red circle around it :)
Mine just went out this morning. I was changing the input from my tv to my computer and heard a “zissst” over the speakers and the power light went out. I will disassemble as shown and look at the transformer.
good luck!
Hi,
Great article!
I stumbled upon it when trying to disassemble mine – one of the fuses in the apartment was down and when i switched it on the z506 was the only thing not powering up.
I checked the transformer and its all blacked and shattered.
Any chance anyone knows the details/characteristics for the transformer?
I wanted to buy one and replace it
Check the update in the last paragraph of the article. I replaced mine with a laptop powersupply. There’s also a link to an online store where you can purchase a direct replacement. Otherwise anything 16-20V 4A+ should do the trick.
How did you hook up the laptop psu to it? Did you open up the charger and take out the relevant bit?
I took the speakers PSU out and cutoff the plug that it connects to the speaker’s amp with. Then I cut off the laptops plug, and switched it for the speaker’s one, so the laptop charger can plug into the amp. I didn’t put the laptop charger in the sub-woofer with the amp, I kept it separate.
Just a question, in your image where is the speaker connection and the amp connection? Do you still use the psu board or it is direct to the laptop charger? Sorry im not that technical when it comes to electronics. Thanks
Hi Bruce
Have a look at this picture.
The connector in red goes from the PSU to the amp. The connector in blue supplies the AC power from your household outlet, let me know if that’s not what you were asking.
The PSU no longer works. No matter how much power you put through it, nothing’s going to happen. So I completely removed it. And connected 18V DC (from the laptop charger) directly to the connectors on the wire at the red connection..
Got it. Thanks Gareth.
Thanks for sharing your solution to this problem Gareth – it’s been very helpful! I have a couple of questions about connecting the laptop charger; I was probably a bit naive in believing the lap top cable would simply have two interior cables to connect to the amp but when I cut into my old Dell charger I’m faced with 3 in a coax type structure – (see photo here http://i.imgur.com/SBly9Rj.jpg) – Can you advise please?
Also this charger is only 19.5v/3.4A and I have another 15v/4A neither of which fit your guidance of 16-20v and 4A+ but thought I would check if you think either of these might work?… otherwise I’ll keep looking in my ‘old charger box’!
Thanks in advance
Johnny
Hey Johnny
Either PSU will probably work, seeing as you’ve already cut open the Dell charger, you might as well use it. Dell chargers have two wires supplying power (a positive and negative) and a third signal wire that tells the laptop what kind of charger is plugged in. Laptops prevent charging using a non-Dell charger. This ‘intelligence’ seems to be only on the laptop side though, and the charger provides full current regardless of what you plug it in to.
That being said, the outer wire is ground, the in-between wire is positive and the inner wire is the signal which you can leave disconnected.
More info and image.
That being said, if you have a multimeter, I very much suggest checking voltage with it before connecting to your speakers.
Good luck.
Hello,
Do you know what the specifications of the original power supply is by any chance?
I’ve just got hold of a Z606 which some had tried to repair the PSU, but failed and binned just the PSU.
I’d like to try and get it working, so looking for a power supply I can use that might match the original specs.
I don’t know the exact spec. I believe it’s 16V @ 5 A. Anything in the 16-19V range should work. While it may work with just a 2 A power supply, you won’t get full power from it.
any way to put a bigger amp in
Take the current amp out, and put a new one in. Any hifi is just an amp + speakers. You can use the speakers in the Z506 with any amp you desire, just need to rewire.
What a great article — very well written and understandable! However, I think I’m going to just replace the sub woofer, as I found one on Ebay for $20. I did enjoy your article, though!
anyone know how to hot wire the subwoofer to work by it’s self? I suspect connecting a couple of pins on the 9 pin connector will turn it on. Any one have any data on the pin outs?
I don’t have my speakers anymore, but the easiest way is probably just to disconnect the wires to the front left speaker, and not plug the others in.
I only have the subwoofer…
Ah. That makes sense. As you suggested, try figure out if there’s a ground pin, or just use the shell. Try short ground and each pin and see if any of them power on the system. There’s also a volume control on the speaker, so you’ll want to get a potentiometer to connect the volume pin to the ground as well.
Unfortunately I don’t know which pin is which. You can probably figure out more if you open it up and inspect the PCB.
Thanks for the ideas. I’ll give it a try. Surprisingly no info i can find online for the pin out on that 9 pin connector….
did you figure out which pins on the DB9 connector turn on the power & volume control? i’m in the exact same situation (subwoofer + no right front control speaker)…
Hey Lennie, I haven’t had this speaker since 2016, so can’t help. Try replying to one of Joe’s comments to see if he can help.
I had a Logitech system (can’t remember the Z number) the setup was just two speakers which did everything I asked of it until one day the system just stopped.
Logitech kindly provided me with a replacement (different system). I held on to the old speakers and tried a suitable old external PSU’s and it worked just fine so I have 2 sets for the price of one.