Logitech Z506 power supply

[Th3_uN1Qu3]

Re: Logitech Z506 power supply

That's a fairly easy board. If you get no signal then it will either be the opamp or the coupling capacitors between the opamp and the sub amplifier. Trace the circuit back from the input pin of the sub amp and replace any capacitors that are in series with the signal, then report back. You only need a DMM with continuity checker (beeper) for this job.

[Joun]

Re: Logitech Z506 power supply

Thank you for answer.I was hoping it will be you who answers since I can tell you have a lot of knowledge..
I can trace it back(it is a little hard but I can do it) and I have the datasheet of the amplifier ic.And I have instruments to check capasitors and signal presence(esr meter and oscilloscope).
I think the problem is before that somewhere in the volume ic or in the opamps ..
I will check it tomorrow and write back.

Thank you!

P.S Do you know who the opamps are?The printing on them is very faint..

[Joun]

Re: Logitech Z506 power supply

P.S Do you know who the opamps are?The printing on them is very faint..

Nevermind, found it in this thread..

[Joun]

Re: Logitech Z506 power supply

OK, I don't need it anymore,it had a broken copper trace on bass volume..

[stromm]

Re: Logitech Z506 power supply

I caved. Target online has the Z506 for $50US. The local store price matched, so I bought two.

I am starting to think this set is nearing discontinuation. None of the computer stores around here carry it and say they can't order more. With that and the price drops, the years I spent in electronic/computer retail makes me think they are short lived.

At least I can now play around with the failing set more leisurely.

[Th3_uN1Qu3]

Re: Logitech Z506 power supply

OK, I don't need it anymore,it had a broken copper trace on bass volume..

Good job!

[rayfloyd170]

Re: Logitech Z506 power supply

I have the same speakers, I replaced a dozen caps already. the problem with my z506 is that there is unusual cracking intermittent sound esp during cold start-up. could it be with the op-amps? I have checked about 50% of the filter caps by a capacitance meter and already replaced those already 10% below the rated capacity.

also I already replaced the potentiometer as I subject it to be faulty. but still the problem of cracking sound occasionally comes. after some time of running, the speakers gets fine.. I think there has to be some caps that needs to be replaced or what? pls help me (newbie here)

[Agent24]

Re: Logitech Z506 power supply

Do you mean crackling sound? Can you clarify if the sound is cracking or crackling, because they are quite different and could be caused by different kinds of faults. Can you make a recording of the sound and upload to somewhere (like soundcloud) so we could hear it?

Have you checked for bad solder joints? You may have a problem with some bad connection that expands and makes a good connection after it warms up.

[GeoX]

Re: Logitech Z506 power supply

A little update: That "burned resistor" was not burned, rather the blackish spot was (stubborn) degraded glue stain. The resistor measured fine (removed off the board to check and measure). Everything around that TOP258M I.C looks good (although the state/condition of the I.C is still unknown), except that failed diode at the turn-off snubber section. Then found 2 more failed diodes (RL205) at the primary rectifier section.

Thus decided to replace all the failed components I've found so far...

- 1x T3.15A 250VAC with 1x Wickman TR5/372 T3.15A 250VAC
- 2x RL205 (2A 1kV) with 2x RL257 (2.5A 1kV)
- 1x 1N4007S with 1x 1N4007

Then connect to the mains power and see what would happen. Aye, I'm expecting some components to get blown up again. Putting a light bulb in series would not be much fun...

Sure enough the same components replaced got toasted.

Looking back at the "path of destruction", one conclusion is that ceramic disc capacitor with the markings "68 1kV" (possibly 68pF). Could be breakdown at high voltage (encounter such problems before). And this capacitor is literally touching and/or pressed against the heatsink (not hard to see why this capacitor can fail). Also hardly any space to manouvere the capacitor away from the heatsink (plus squeezed in on the other side by the big main filter/smoothing capacitor), and the through hole is literally almost on the edge of one of the the heatsink sides...

Replacing that capacitor decision time. My options are...

#1. Use back a leaded through hole capacitor, which means the new capacitor will be literally touching the heatsink again! Besides ceramics, another option would be silver mica capacitor (rated for 150C).

Or...

#2. Use SMT ceramic capacitor (125C ones) which can be placed away from the heatsink, on the bottom of the PCB.

At the moment, option #2 looks interesting. What do you guys think?

Hey Im new here, I have a Z 506 which died (power supply pcb) a few years ago.
Finally got round to investigating and found a plug-in DC adapter with 15V 2A output. Works perfectly. Only snag now is polarity of the bass when reconnecting to main pcb... Do you think it matters? marking on pcb is vague! Hope you can help please, cheers

[Th3_uN1Qu3]

Re: Logitech Z506 power supply

It won't really matter unless you have another subwoofer besides this. Phase issues, "nulls" only occur when there is more than one speaker reproducing the same frequency range. Either way will work.

[Khron]

Re: Logitech Z506 power supply

Absolute worst case, if the bass speaker's connected with the wrong phase, you'll get a dip around the crossover frequency (which, in this case, i'm guessing might be anywhere in the 100-300Hz area?). If you find that music's sounding a bit "hollow", it shouldn't be too hard to reverse the two wires, i think

But considering these were cheap-ish to begin with, who knows, they might even end up sounding better with the sub reversed

[andris0]

Re: Logitech Z506 power supply

Hi!
I have a Logitech z506 . The power supply has spent a diode and a resistor . The diode FR207 resistance 100ohm . And there are none for me. It could be used instead of the 12v power supply ?
Thanks!

[andris0]

Re: Logitech Z506 power supply

I would also like to ask that the power supply is a resistor R2 . How many and what kind ohms could be done instead ?
Thanks!

[momaka]

Re: Logitech Z506 power supply

A little late of a reply, but here it is anyways...

I would also like to ask that the power supply is a resistor R2 . How many and what kind ohms could be done instead ?
Thanks!

R2 = 10 Ohms, 5%, and 2 or 3 Watt (not sure about that one)

Also read the first page of this thread again. Apparently diode D5 likes to go bad too sometimes when R2 fails. So make sure to check D5 and replace if bad. Th3_uN1Qu3 used a 3A 1000V fast recovery diode and reported good results, so you may want to use something similar for D5 (i.e. something like a HER307, PR3007G, etc.)

[melih]

Re: Logitech Z506 power supply

Sorry to wake up this old topic but even me i have same problem guys hopefully will help to others so that's why im putting here. My problem is this sound system working only 45min or 1 hour after sound not coming at all when im unplugging the power cable after cooling down i can able to listen music.

At home there is one Laptop Adapter 19v 4.74a i dont know it is suitable or not but with calculation around 90w.

If this Power unit able to repairable i can do just here im wondering about radial leaded bobin coil and FUSE %100 gone. My thoughts is this bobin coil values i dont know them they used normal cover on it no values burned all.

Here some pictures. If anyone have circuit diagram with all values about component i will be grateful.

[Agent24]

Re: Logitech Z506 power supply

Please add photos in another post - on your first post I don't think you can add pictures but after that you can.

Do you have freezer spray? You may try to use that to find an overheating issue...

[melih]

Re: Logitech Z506 power supply

Pictures added. Other components i didint checked but everything seems okay. I am curious about what values needs for that bobin coil. I brought some componenets whihc i can able to read. I am adding their photos too but i learned values from this forum.

Bobbin Coil shop seller talked about 100 something like that i dont know which i brought there is no value on it.

[Agent24]

Re: Logitech Z506 power supply

Does the power supply still output correct voltage after the speaker stops working? Then you can find if it's a power supply or speaker problem.

It seems these can handle 19v OK, going by the earlier posts in this thread, so you could test it with the laptop charger, sure.

[melih]

Re: Logitech Z506 power supply

Does the power supply still output correct voltage after the speaker stops working? Then you can find if it's a power supply or speaker problem.

It seems these can handle 19v OK, going by the earlier posts in this thread, so you could test it with the laptop charger, sure.

Yea i dont want to burned out the speaker system because here currency issues they get expensive now. So if this laptop charger is okay im gonna buy it and mount inside box everything will be fine. Hopefully

[melih]

Re: Logitech Z506 power supply

Hi, Guys new update before sound system was working around 45 min after power supply i updated with brand new notebook adapter. Now working only 3 hours after cooldown will work again 3-4 hours now What im gonna do now i dont know