#104

This speaker was described as "blown" and offered for cheap. The problem was traced to a shorted MOSFET on the primary side of the switched mode power supply and one dead electrolytic capacitor on the secondary side.

[@PapasDino]

It's amazing how much I've learned about troubleshooting from your video adventures, thanks!

[@gordonwedman3179]

Never any doubt in my mind that you would be able to fix it. Interesting to see that cap looked perfectly fine but was very bad .

[@jonathanr2830]

Glad that the speaker turned out to be a good purchase and investment for you. Congratulations on your win! Also, thank you very much! I enjoyed watching your interesting work and learning about skilled troubleshooting to resolve such problems or mysteries, one might say. All the best!

[@patvaughanmusic]

Great video, great job, and thanks for sharing your talents and experience with us.

[@sappk4908]

Wow that’s awesome repair 🙌

[@davidnewmister2290]

Thank You for the video. It gives me an idea about how to troublshoot my weak volumed K10.

[@DeadKoby]

Cool. Switching power supplies are my weak point... nice to see one get fixed.

[@jrinventormusic]

also, your video here is awesome. really enjoyed the pace and information. I think I need to look into a few new tools :)

[@danieltyger6387]

"Let's play a piece of royalty-free music." - a consummate professional!

[@cachitodeamor766]

Good Job Doctor circuit thanks for u time and knowledge

[@ServiceOrchestramegastore]

well done, learnt much.

[@johnsweda2999]

You might find these components at rs-components or CPC

[@johnners911]

Hi, thank you for the videos. They are very informative. I have a pair of monitor speakers on which the volume is very low from the active speaker, but perfect from the passive side. I think the drivers are fine but I'm not sure where to start looking for the fault!

[@tyronenelson9124]

All qsc active subs and tops seem to use really junk and unreliable switch mode power supplies. And why on earth have they used such a small pair of output transistors to drive such a powerful load?

[@yusdiy]

Great work. Yes one more for stereo set up.

[@jp040759]

Great video as usual.

[@astalavistatomi]

Hello, perfect video. Can You make video about that Variable AC supply? Thank You for Your work

[@andymouse]

Nice work !...cheers.

[@markgilbert9930]

It's never the fuse... Nice job!

[@midnightwind8067]

I see many videos with these problems from multiple brands. Do you think this is an in rush issue?

[@jdmccorful]

Good fix!

[@MrPiotrek55555]

you can tell me what part happened because I had a short circuit on the 16V capacitor on the DSP module. The DSP module is not damaged after I checked there is no 16V power supply from the power amplifier module to the DSP board. what element affects the power supply of the DSP module so that I know where to look?

[@peerybrown]

Did you say you want one more....to repair? HAH! I have two, and one is going into thermal protection at around 0db, and it is worse when I have the low freq. set to deep. I think I will open it up and make sure that I don't have a cold solder joint or that it isn't tight against the heat sink. Really good speaker for the size! Is that a Heathkit AC supply?

[@CyrusGQ]

Hi, I would like to know where I can learn how to do what you did in this video. Do you have any DIY resources I could explore to learn more?

[@tonyvasquez759]

how would you diagnose a temperature switch other than the fan not turning on (fan has been tested and functional )

[@tiktokmashup4840]

hi sir which part is broken? Peak problem but no volume

[@davidkenneth3983]

Jbl eon 15in w horn g2 those 2 black things im suspecting the one im checkin is a trowaway 15in jbl eon g2 nice as hell when working need to fix no exp. Dont k n ow if theres a fuse its just an extreme drop in volume very extreme so its imperativecto succeed. Wish someone had an eon black g2 to work on its low vol. Now and is useless?

[@jkbass546]

What made the OP think it was blown? Was the sound fuzzy?

[@feedback-loop]

the thing was completely dead

[@musikaband6849]

HELLO I HAVE AN M AUDIO AXIOM THE SAME ONE THAT IS IN THE VIDEO. A FRIEND CONNECTED IT TO A HIGHER VOLTAGE POWER TRANSFORMER AND THE DISPLAY NO LONGER TURNED ON AND ONLY A FEW PUSH BUTTONS TURN ON WHEN I CONNECT IT WITH THE USB CABLE. YOU THINK I HAVE A SOLUTION?

[@tyronenelson9124]

You may have blown the linear regulators.

[@giovannipg3000]

Hello...mine k12 stays led green and red on....i tested mosfets and they are good....what else could it be ?

[@miroslavvujadinovic6724]

I have lights red and green on my qsc k 10. Please help my what is problem?

[@jrinventormusic]

Hey, I have a QSC K10 that doesn't pass audio but the signal shows up on the LED of both channels...What DOES happen is that the limiter LED stays illuminated red as soon as the unit is turned on. Any ideas where to look? C25 doesn't look hurt...

[@feedback-loop]

Do you really think that it is possible to give any advice based on such information?

[@jrinventormusic]

@@feedback-loop lol if it's you asking? I'd answer no. I'll have to just start having fun with it I suppose...I'll try to track down a schematic and try to see where the signal is getting blocked out...

[@richardcrump4158]

On my QSC my light green light just blinks but it does not play sound don’t come out don’t know what to do

[@dynasty441]

@@richardcrump4158 speaker could be blown, i had that issue with my Ks118 subs,

[@marcobarbosa3467]

Hello, I have a pair of QSC K12 speakers and one of them keeps overloading and disarming. Any help tip will be much appreciated. Thanks!

[@tyronenelson9124]

The psu is failing.

[@jrinventormusic]

@@tyronenelson9124 what happens to the power supply unit? that section is under the silver metal housing inside the unit right?

[@jesusnavarro5255]

Where are you from ?

[@LovacNaDrolje]

👍👍👍👍👍👍👍👍

[@otherbasis8505]

What kind of silicone did you use to bond those caps to the PCB?

[@feedback-loop]

I used K-704 RTV that I had handy. It stays flexible, unlike the original stuff. Perhaps I should have used harder stuff similar to the original, but I did not have anything like this at the moment.

[@otherbasis8505]

@@feedback-loop Thanks!

[@andreavico6198]

I have a similar unit that overheat after I repair. My suspect is the transformer, could you measure the inductance of the primary winding?

[@andreavico6198]

www.eevblog.com/forum/repair/1kw-active-clamp-flyback-smps-with-too-high-idle-current/

[@feedback-loop]

Oh, I don't feel like taking it apart again.

[@Ogma3bandcamp]

@@feedback-loop Could you measure it across the mains socket in the back of the speaker? Just wondering.

[@andreavico6198]

@@feedback-loop ok

[@andreavico6198]

@@Ogma3bandcamp no, it don't work. There is a lot of component between the primary of the transformer and the mains socket.

[@cachitodeamor766]

I would like you to give video calls as help to fix our equipment if it could be clear with your payment in advance ---me gustaria que diera videollamadas como ayuda para arreglar nuestros equipos si se pudiera claro con su pago por adelantado... gracias

[@ronniebrown8775]

you find the problems so fast compared to me lol

[@feedback-loop]

It just seems that way in videos

[@rocaduradj6390]

thanks mr Repair Electroman i'll will check by my self one amp that is no working and you hel p me on this video

[@alfredneumann4692]

Here in Germany digi-key is veeery expensive.

[@feedback-loop]

You have some other distributor that would be expensive for me, right?

[@alfredneumann4692]

@@feedback-loop You would not have a reason to buy here. You have enough distributors. The distributors, which we have here (digi-key, RS-Components, Farnell, to name the big ones), are heavy expensive. The other ones (Conrad, Reichelt....) are much more cheaper but don't have by far not this big offers in their catalogs. Thats the problem. You order the mosfet and u get it. I don't get the offer for this. And have to buy it at digi-key or so. Sorry for my bad english.