harmon/kardon sub-ts14 makes high-pitched squeal sound

[gtdavelo]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

I'm following this thread ever since my gf's subwoofer has the same issue... I'm stuck at trying to remove the board and PSU from the wooden shell... all screws were removed... yet no luck.... any help would greatly be appreciated

Dave

[gtdavelo]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

I took apart the boards from the encasing.... found the Service Manual online... but after examining the board with the naked eye, I see no obvious issues.


Any help would be greatly appreciated!

Dave

[lexwalker]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

I took apart the boards from the encasing.... found the Service Manual online... but after examining the board with the naked eye, I see no obvious issues.


Any help would be greatly appreciated!

I spot..... degraded glue!

[ben7]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

Replace the bipolar electrolytic capacitors on the power amp module (the one on the heatsink). I other threads with similar power amp modules, which had bad capacitors.

[mightyeskimo]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

I'm in the same club here folks! LOL. I've included some pics of the crispiness that happened. Looks like I'm gonna have to replace the PCB 104ds15000 for sure and possibly the PCB 104sub15000. However, here's the problem. JBL/Harman doesn't sell the PCB's alone anymore, they are only available as part of the entire replacement Power Amp Class D Module 012-7500-00022 which goes for $177 and change. Would it be worth the trouble to have a custom PCB made and then just replace the bad components after testing?

[budm]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

You may be better of with sub-woofer plate amplifier as the replacement instead 9if the speaker is still OK, just have to modify the cabinet.
http://www.parts-express.com/cat/sub...amplifiers/332

[tpr]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

Hi guys,
I'm new here, hoping to get an opinion of the experts.
Piggybacking on this thread as we're talking about the similar hardware.

I have SUB TS15 which kept off (power switch off) during my recent vacation.
When I came back and turned it on, the sub is working fine when active, but as soon as it goes to standby (led change from blue to orange) it starts creating a low frequency thumping sound which can be only stopped by either starting the music again or turning the sub completely off.

To mitigate the issue I switched it to "always on" mode so that it never goes to standby.

I attached a SM in case someone wants to take a look.

I appreciate any hints on how to resolve this problem.

[budm]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

As you can see in page 31, when unit goes into mute/Standby mode, Q102 is turn ON, which will turn off Q103 and Q104. So, do you hear any rumbling when the unit is set to always ON (buy the way, when it is in standby, the power amp and the preamp are still getting power)? It can be due to unstable power, so you need to check the DC voltage on the +/- power supply filter caps, it can also be that Q102 is not being completely turn on by steady DC but with low frequency DC.

[lexwalker]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

I'm in the same club here folks! LOL. I've included some pics of the crispiness that happened. Looks like I'm gonna have to replace the PCB 104ds15000 for sure and possibly the PCB 104sub15000. However, here's the problem. JBL/Harman doesn't sell the PCB's alone anymore, they are only available as part of the entire replacement Power Amp Class D Module 012-7500-00022 which goes for $177 and change. Would it be worth the trouble to have a custom PCB made and then just replace the bad components after testing?

From the pictures, easily can see degraded glue (again!), blackish PCB area due to heat from those naked heatsinkless transistors and leaking capacitors. Would suggest checking those transistors (possibly replacing them as well) and replace all capacitors on that board.

Hi guys,
I'm new here, hoping to get an opinion of the experts.
Piggybacking on this thread as we're talking about the similar hardware.

I have SUB TS15 which kept off (power switch off) during my recent vacation.
When I came back and turned it on, the sub is working fine when active, but as soon as it goes to standby (led change from blue to orange) it starts creating a low frequency thumping sound which can be only stopped by either starting the music again or turning the sub completely off.

To mitigate the issue I switched it to "always on" mode so that it never goes to standby.

I attached a SM in case someone wants to take a look.

I appreciate any hints on how to resolve this problem.

Had the same problem on different speaker system, and the source of the problem was a badcap on the secondary feedback section (initially I was looking around the primary side feedback area plus changing the opto-isolator, then attention went to the control section)...

[tpr]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

@lexwalker:

Would you be able to point me to the cap(s) that I need to check?
Sorry my hands-on experience is rather limited, but I can check a cap and solder if needed

@budm:

I don't hear any noise when the unit is on.

[fastvideo]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

I spot..... degraded glue!

Lexwalker is right.

First thing you should do is remove and clean all rusted glue between connections and pins of each components on each board.
then the Caps.

[lexwalker]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

@lexwalker:

Would you be able to point me to the cap(s) that I need to check?
Sorry my hands-on experience is rather limited, but I can check a cap and solder if needed

Look at areas around U203/A and U204/A, also subsequent areas after that such as components surround Q206, Q207 and U203/B. Try checking the components around there, and also replace all the capacitors there (especially that C300).

[axlmastr]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

I found a company in Illinois on ebay that does electronic service work. They have individual listings for all of the various plate amplifiers like the subject of this post. They offer to fix it like new again for $145. I have to "Buy it Now" and they give instructions where to ship. I ship it there at my cost and they include return shipping in the sale price.

I know the idea is to repair it yourself, but this is an option.

[exetico]

Re: harmon/kardon sub-ts14 makes high-pitched squeal sound

Hi'

Sounds a bit like the problem i'm struggling with.
Video: (Warning: High sound)
https://streamable.com/dllx

Any suggestions? I'm going to look at the hardware now...