Audio Logitech z623 subwoofer stopped working


nitin_g3

Active Member
Disciple
Hi,

I have a Logitech z623, bought in early 2016. It was working fine except that sometimes the sub used to stop working. The fix was to reinsert the right speaker cable into sub.
This used to be my fix to make the sub work again. I used this fix for whole last year.

But today this fix is not working anymore. The satellite speakers still work fine.

I've tried below fixes but nothing seem to work:
  1. Reinsert the right speaker cable multiple times.
  2. Did some cleaning of the port by blowing air into both male and female using a small manual blower.
  3. Tested speakers using my phone to check maybe it's my computer audio causing the issue, but the problem is still there while I try to play music using my phone.

Any kind of help is appreciated. Thanks.
 

vaibhavyagnik

youtube.com/vaibhavyagnik
Adept
It can be either of the three things
1. The port in which you used to re-insert the cable is completely damaged now. It should be an easy fix at any electronic shop
2. The electronic board of the subwoofer is damaged. Again should be able to get it fixed at an electronic shop
3. The subwoofer speaker is damaged. Again should be easily replacable.
 

nitin_g3

Active Member
Disciple
It can be either of the three things
1. The port in which you used to re-insert the cable is completely damaged now. It should be an easy fix at any electronic shop
2. The electronic board of the subwoofer is damaged. Again should be able to get it fixed at an electronic shop
3. The subwoofer speaker is damaged. Again should be easily replacable.
ok, thanks for the directions

I'll first try to dissemble the subwoofer myself and clean the port with alcohol. Will update here.
 

nitin_g3

Active Member
Disciple
Update: So I dissembled the sub and cleaned all ports using alcohol. But problem still persists.

Can anyone suggest where should I take the system to get repaired in Jaipur or if there are still other fixes which I can try myself at home?
 

puneet.darji

Well-Known Member
Disciple
I also have same speakers and faced exact same issue. I use to fix by replugging that special connector (vga kind) until it stopped working altogether. I tried to go to Logitech service center and they said they only replace it and no repair. I searched locally for any repair shops and found one in Borivali-East (Mumbai). He took 2-3 days and gave up stating he cannot remove the whole board from sub woofer as its very difficult to access. Then I tried and removed the board and again gave him back for repairs. As per him issue was in bass knob and there is no issue in sub woofer. The knob was replaced (exact knob is very difficult to get) and post that everything worked fine. This repair was done last year in around Sept-Oct (just before Navaratri). Repair costed me 2.4k. So i would suggest get the bass knob checked which is present on speaker level and might be easy to repair.
 

nitin_g3

Active Member
Disciple
I also have same speakers and faced exact same issue. I use to fix by replugging that special connector (vga kind) until it stopped working altogether. I tried to go to Logitech service center and they said they only replace it and no repair. I searched locally for any repair shops and found one in Borivali-East (Mumbai). He took 2-3 days and gave up stating he cannot remove the whole board from sub woofer as its very difficult to access. Then I tried and removed the board and again gave him back for repairs. As per him issue was in bass knob and there is no issue in sub woofer. The knob was replaced (exact knob is very difficult to get) and post that everything worked fine. This repair was done last year in around Sept-Oct (just before Navaratri). Repair costed me 2.4k. So i would suggest get the bass knob checked which is present on speaker level and might be easy to repair.
Thank you so much. Very much appreciated.
That's what I like most about tech forums. There's always someone who has already faced the problem which you just faced and probably already found a solution.

I'll try to dissembled the right speaker myself and take the bass Knob to repair shop and try to find the replacement.
 

Ebil

Active Member
Disciple
I also have same speakers and faced exact same issue. I use to fix by replugging that special connector (vga kind) until it stopped working altogether. I tried to go to Logitech service center and they said they only replace it and no repair. I searched locally for any repair shops and found one in Borivali-East (Mumbai). He took 2-3 days and gave up stating he cannot remove the whole board from sub woofer as its very difficult to access. Then I tried and removed the board and again gave him back for repairs. As per him issue was in bass knob and there is no issue in sub woofer. The knob was replaced (exact knob is very difficult to get) and post that everything worked fine. This repair was done last year in around Sept-Oct (just before Navaratri). Repair costed me 2.4k. So i would suggest get the bass knob checked which is present on speaker level and might be easy to repair.'

how come a bass knob F everything else? stupid design !
I have the same speakers which stopped working early last year. I get no indication of power so I thought its a issue with the power supply board but I didnt have time to get it fixed so its just lying around.

Do you think it could be that bass knob for me too? and isnt the bass knob on the satellite speakers?
 

puneet.darji

Well-Known Member
Disciple
Yes, bass knob is on the satellite speaker. I would suggest just give a try you never know. Even I was surprised when came to know that bass knob is the culprit. I had spent almost 3-4 hrs. to dismantle the whole sub woofer and take out the main board from it and finally got to know issue is in bass knob its like 'Khoda pahad nikli chuhiya'. As per the technician, bass knob was not supplying power/signal correctly to the woofer, hence woofer stopped working. I didn't poked around much as anything more it would have gone over my head. And technician has promised himself not to repair such speakers in future (He is into speaker and amplifier making business). As per him design of board is so confusing and all the parts are so compact and small. This is why it took long time for him to diagnose and solve it.
 

nitin_g3

Active Member
Disciple
Hey @puneet.darji
I dissembled the right satellite speaker myself just to check and components. I believe I can solder the new subwoofer knob if I can get one. Can you please help me with this ? What should I tell the electronics repair guy to get this exact part?
Should I carry the whole speaker set?
 

puneet.darji

Well-Known Member
Disciple
Hey @puneet.darji
I dissembled the right satellite speaker myself just to check and components. I believe I can solder the new subwoofer knob if I can get one. Can you please help me with this ? What should I tell the electronics repair guy to get this exact part?
Should I carry the whole speaker set?
I'm not sure what is the name of the knob. I suppose there is some alpha numeric number on knob starting with R (not sure though). Either you can ask for the part with this number or show it to the repair guy and ask for exact part. Carry the speaker set only if you want to test it.
 

nitin_g3

Active Member
Disciple
I'm not sure what is the name of the knob. I suppose there is some alpha numeric number on knob starting with R (not sure though). Either you can ask for the part with this number or show it to the repair guy and ask for exact part. Carry the speaker set only if you want to test it.
So the part number is b103 on my knob. I took pictures of the circuit board and showed it to a dozens, I repeat, dozens of shop keepers in my local radio market (in Jaipur). And no one had the part. They were not even taking interest in looking at the picture of the circuit I was showing to them.

Also I can't find any online store which sells audio components. Please let me know if anyone is aware of such store.
 

puneet.darji

Well-Known Member
Disciple
Try with generic one. Not sure if it will work/fit exactly as original. Also can you post the picture of the knob here, I will try to check here in Mumbai.
 

nitin_g3

Active Member
Disciple
Try with generic one. Not sure if it will work/fit exactly as original. Also can you post the picture of the knob here, I will try to check here in Mumbai.

Yesterday I approached a local audio repair guy. He tested the bass potentiometer by directing it. He concluded that there's no issue with bass knob at all since if it was faulty then bypassing it should have made subwoofer work on full bass. But that didn't happen. Can you tell me if you've also tried bypassing when yours was dead?

He then said that he'll have to send it to someone to get repaired and most probably the issue with the IC in the subwoofer. He also quoted max 2000 as repair charges.

Below are the pictures since you've asked. It's a 6 pin potentiometer.

IMG-20210403-WA0000.jpg
IMG_20210403_114529.jpg
IMG_20210403_114522.jpg
 

sbhas2k

Well-Known Member
Adept
When the potentiometer fully turn up or down, did the speaker work earlier. Also, I assume there is no off switch when fully turned down which some know has ? If the answer is yes, then what he said was right

Potentiometer ‐ basically increase or decrease the resistance, so frequency can be lowered or increased as required for the base
 

nitin_g3

Active Member
Disciple
When the potentiometer fully turn up or down, did the speaker work earlier. Also, I assume there is no off switch when fully turned down which some know has ? If the answer is yes, then what he said was right

Potentiometer ‐ basically increase or decrease the resistance, so frequency can be lowered or increased as required for the base
Yes it worked earlier when fully turning up and down. There's no off switch when fully turned down.
 

puneet.darji

Well-Known Member
Disciple
Yesterday I approached a local audio repair guy. He tested the bass potentiometer by directing it. He concluded that there's no issue with bass knob at all since if it was faulty then bypassing it should have made subwoofer work on full bass. But that didn't happen. Can you tell me if you've also tried bypassing when yours was dead?
In my case he attached some other knob temporary to check and with it, subwoofer starting working though not upto the mark. Hence the repair guy concluded that it was knob which is the issue. So swapped out with new and it started working.
 

nitin_g3

Active Member
Disciple
Update: so I gave it to a local guy for repair. He then sent it to another repair guy. They fixed it in a day. Total repair cost was 1900/-.
I asked for details like what was the issue, they didn't tell me stating that it was something they don't share. Just told me that they repaired something in IC.
 

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