Logitech Z506 power supply

[stromm]

Re: Logitech Z506 power supply

I'm assuming these are not in good shape?

[stromm]

Re: Logitech Z506 power supply

Thanks Agent24 for some more direction.

Power is removed from mains. My life is fairly busy lately, so it'll be a couple days before i can take apart the main unit to get some pics and do the test you suggest.

Will post again when I do.

[Agent24]

Re: Logitech Z506 power supply

No luck with headphones. The system presents sound till it seems like something warms up, then cuts out unless the volume is up all the way. Even with headphones connected.

Once it starts cutting out, if I remove power (cord) for five minutes or so, then plug it back in, I'll get sound as normal for a few minutes.

Does this seem like the power supply board?

I don't know. Others in this thread have certainly had problems with the power supply.
When you disconnect it from power for five minutes, do you disconnect the mains power from the wall or just the power supply from the amp?

If you have been disconnecting it from the mains, try just unplugging the power supply from the amplifier, and see if again it works after 5 minutes. You could also try measuring the power supply voltage and see if it changes between when the amplifier works OK and when the problem occurs.

It may also be something overheating or such in the amplifier itself. Can you post photos of the amplifier board so we can see?

If the amplifier section is bad, you might have to trace the audio signal through the amplifier and see where it goes wrong.

[stromm]

Re: Logitech Z506 power supply

test with headfones, there is a pair of switch contacts in the jack that can tarnish.

No luck with headphones. The system presents sound till it seems like something warms up, then cuts out unless the volume is up all the way. Even with headphones connected.

Once it starts cutting out, if I remove power (cord) for five minutes or so, then plug it back in, I'll get sound as normal for a few minutes.

Does this seem like the power supply board?

[stj]

Re: Logitech Z506 power supply

test with headfones, there is a pair of switch contacts in the jack that can tarnish.

[Agent24]

Re: Logitech Z506 power supply

Might be best to take a look at both. I say check anything that gets moved around first as it's more likely to fail. Try wiggling plugs etc and see if that also solves the problem. Then you might find out at least which board is the problem.

But bad solder joints can occur due to bad soldering from the factory, such as with mine - I never used the headphone jack either. So it's not always what you'd expect.

[stromm]

Re: Logitech Z506 power supply

Thanks for the info Agent24.

I have never used the headphone jack on the FR speaker. The wires don't get moved around either.

Do you mean the subwoofer unit PCB or the controlign speaker PCB?

[Agent24]

Re: Logitech Z506 power supply

I had a very similar problem with a pair of cheap 'Milford Sound' speakers (TDA2282 based)

The problem was cracked solder joints on the headphone jack.

I'd suggest that to start with you inspect the PCB for bad solder joints and reflow any that look bad, also on anything that might take physical stress (like input\output jacks), volume control potentiometer itself, etc.

A more systematic approach would be to do signal tracing through the board, but it may not be necessary.

[stromm]

Re: Logitech Z506 power supply

Hopefully it's OK to tag into this thread, I think my issue is related.

My z506 will present sounds for a few minutes at best. Then nothing. Power light is solid and stable. To get sound back, I must turn the volume dial to max. Oddly, with the volume at max, it never cuts out. However, there is quite a bit of background hum so if I turn down the input volume, that hum is too much.

I have tested different power sources, different audio sources (stereo and surround) and every case exhibits the same problem.

Does this sound like a power supply issue or something else?

Thank you for the help!

[ben7]

Re: Logitech Z506 power supply

Hey i used a 18.5v and 3.5A power brick. The speakers are working fine, but the volume controlling nob get heated a little bit. Why is that??

That is probably normal, it's heat from the components on the circuit board getting transferred to the volume control potentiometer, and to the plastic knob.

-Ben

[DamiYa]

Re: Logitech Z506 power supply

Hey i used a 18.5v and 3.5A power brick. The speakers are working fine, but the volume controlling nob get heated a little bit. Why is that??

[momaka]

Re: Logitech Z506 power supply

Ive got a dell 19v 3.4amp, will it do the job or is it overkill? i dont wanna go frying the thing.

A bit of a late response, but YES, this should work fine.

[KMpuggy]

Re: Logitech Z506 power supply

Hi, me too have had issues with the PSU on this.

I brought one of that well known auction site, said it was "brand new" came in a tatty box and to me looked like it had been used. Anyway i wernt to bothered if it was, thats if it worked anyway. Wouldnt power on at all so mailed the seller and they sent me a full replacement system and they have told me to keep this faulty one, bonus.

So ive got this to tinker with and after reading through the whole of this thread i guess it was the psu. I couldnt see anything noticeable wrong with it and im more of a mechanic than an electrician so instead of attempting to sod about finding the fault/s and fixing the psu i was going to fit an old laptop charger ive got lying around.

Ive got a dell 19v 3.4amp, will it do the job or is it overkill? i dont wanna go frying the thing.

cheers

[Th3_uN1Qu3]

Re: Logitech Z506 power supply

It'll work on 12 volts but the power output will be a bit lower. With the engine on, alternator running you have around 14 volts which will do fine.

[matheuslps]

Re: Logitech Z506 power supply

Hello guys,

Just dropping some words.

This topic help a lot. I was curious to know how this z-506 is inside.

Mine version has a full range power supply, 110 to 240V an is a little different inside.

I opened it to see the contents but was unable to take of the main sound board. It seems it is stuck with glue on the back. And the power supply board has two screws that i could not remove because I do not have a small tool to use inside the wood case.

But I could measure th voltage the power supply is delivering to the sound board. I measured constant 16.5V with no sound and with sound.

My goal is try to use this multimedia with a 12V batteries from a car (13.8 with engine on?). Maybe will I need a booster converter to step-up the 12V? If I have some time today, I will try put 12V direct to it and see if this can work.

If I can de-stuck the sound board, I wil take some pictures and post here to help this topic with more info. Really, I searched A lot through google to find info like this....

Bye

[momaka]

Re: Logitech Z506 power supply

It seems odd they are using a general purpose diode and not a fast one there, I always saw diodes like FR107, HER103 etc used in those places.

I agree.
Fast recovery diodes are a much better choice in a snubber network. When the transistor goes off, you need something to conduct the energy from the inductive kickback fast. Otherwise, the voltage spike could be quite high. The lower the reverse recovery time, the faster the diode will clamp the spike. The capacitor-resistor parallel network is also important in terms of how high the voltage spike stays once the diode conducts.

[lexwalker]

Re: Logitech Z506 power supply

It seems odd they are using a general purpose diode and not a fast one there, I always saw diodes like FR107, HER103 etc used in those places. But maybe it's not the diode, and you have some other problem.

Usually I would expect something like FR107 or UF4007 in those locations, instead of 1N4007. Anyway, I've seen normal diodes used in some switching power supplies before (as snubbers). As for the source of the problem, the only essential part that I did not replace was the transformer. The rest (including the zener diodes, optocoupler, capacitors, resistors, rectifier, etc) have been replaced. Did manage to get it to almost full volume in stereo (unlike previous brown out which happens at half the volume only), but the moment I had connected all the satellites for the rear and center channels then the power supply went kaput again...

[Agent24]

Re: Logitech Z506 power supply

The original diode was an 1N4007 (weird choice for the snubber), in fact. Just keeps blowing up whenever the power supply fails. So I put an 1N5408 diode there

It seems odd they are using a general purpose diode and not a fast one there, I always saw diodes like FR107, HER103 etc used in those places. But maybe it's not the diode, and you have some other problem.

[lexwalker]

Re: Logitech Z506 power supply

"I'm beginning to guess that the transformer was the culprit (also found the primary coil measures almost nothing, about less than 0.3 ohm only" it has low resistance because you are measuring the DCR (DC resistance of the transformer winding), the transformer is made to be connected to high frequency switching DC by the SMPS, at those frequency, the impedance will be much higher than DC resistance. You have to use ringer tester and LCR to verify the transformer.

No. Transformers work on AC or pulsed DC - resistance as measured with a common multimeter on the ohms range (which works in DC) is irrelevant. Actually, the lower the resistance, the lower the losses in the wire.

Aye, I know a LOPT/FBT tester would be required. I just did a quick measure after pulling it out and before relegating it to the garbage bin. Around 0.3 Ohm is probably the limit of my multimeter for DC resistances below 1 Ohm, has an error offset of around 0.2 Ohm to 0.3 Ohm (which is why I've mentioned it measures almost nothing).

Good job. That's kinda overkill tho - a 65W brick would have done the job just fine.

I've also had a much smaller 64W Sony brick (output was 16V 4A), but I thought the HP adapter with higher power output would be better. Anyway, the Sony one was only half the size of the HP adapter and is actually smaller than the original Logitech one, thus that kinda worries me...

[Th3_uN1Qu3]

Re: Logitech Z506 power supply

At this point, I'm beginning to guess that the transformer was the culprit (also found the primary coil measures almost nothing, about less than 0.3 ohm only)...

No. Transformers work on AC or pulsed DC - resistance as measured with a common multimeter on the ohms range (which works in DC) is irrelevant. Actually, the lower the resistance, the lower the losses in the wire.

Thanks for the advice, I went this path after giving up on the original power supply. Found a nice 90W HP adapter and did some modifications to the original board so that I could mount it inside rather than left hanging outside.

Good job. That's kinda overkill tho - a 65W brick would have done the job just fine.

"I'm beginning to guess that the transformer was the culprit (also found the primary coil measures almost nothing, about less than 0.3 ohm only" it has low resistance because you are measuring the DCR (DC resistance of the transformer winding), the transformer is made to be connected to high frequency switching DC by the SMPS, at those frequency, the impedance will be much higher than DC resistance. You have to use ringer tester and LCR to verify the transformer.

Indeed.