Troubleshooting Harman Kardon TS-14 Subwoofer

[retiredcaps]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

what are supposed to be rubycons (can any of you spot fakes?).

Yes. Post pictures of the top and bottom of the cap. The top should look like a "K" vent.

[lti]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Those caps might not work. The originals are nonpolarized and the new ones are polarized.

[jmbjr10]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Found this cool site while looking for some answers on my sub. Started off intermittent, switching it on and after a minute of thumpage, going into standby. Now when I switch it on, it is trying to turn on but it cycles back into standby, continually. I took it apart and damage wise it looks to be this. Apparently it overheated and melted the coating, but am somewhat newbage and am unable to figure out what the specs are to this, resistor?

I had the same problem and it seems we are in the same boat. C16 & C17, L1
are all obsolete parts and I found some caps that are (non polar 10 uf 100v 20%), however I can't find a replacement for L1 (choke coil 35 uh ferrite core 25) I clean up the board and installed the caps left L1 in however It still doesn't work. If you are able to find some let me know! jmbjr10

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

The caps (BI-POAR) and the Inductor are part of the output filter of the Class -D switching power amplifier. The Inductor is OK, the caps are the most common failure in these sub-woofer Class-D power amp.
Here is the Cap: http://www.mouser.com/ProductDetail/...EETKeRgSqTI%3d

Get extra.

[Khron]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Bipolar electrolytics as Class-D output filtering? Really? I mean i know it's a subwoofer, but still... They'd be seeing huge-ish ripple voltages

Is the amplifier in this supposed to have a transformer output or something? I can see *one* FET in TO-220 case in THIS photo, with its drain pin going to what looks a (flyback?) transformer, as can be seen HERE. Or wait, i think i spotted the silkscreen for a second one, right "under" the transformer...

It'd be nice to get a shot of that board with the output filter(?), with the two crap(ped) caps removed.

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Output transformer? To poduce 35Hz at 200W, that will be big transformer.
It is poor designed to use Electrolytic caps in the output filter (the LC filter is used for filtering out the switching frequency of that Class D amp uses). There is no output transformer in these Class D-sub woofer system. Copper and steel cost a lot of money, Class D- output MOSFET' s voltage will swing from B+ rail to B- rail with varying pulse width, since the output will swing both directions with reference to circuit ground that is why you need bi-polar caps. The power supply is bi-polar (b+ & b-). Look up on how Class D work, newer design use filter-less output filter. The power supply uses Toroidal transformer.
Here is the service manual, see page 28 for the power amp section.

[Khron]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Oh, wait, is that transformer-like-looking thing, on the power amp daughterboard, that 120uH output inductor?

EDIT: Apparently it is... Part list says L1 has an EFD-30 core.

Yes, i'm aware of the "anatomy" of class-D amps, i'm just... well... nearly appauled to see ELECTROLYTICS used as output filter caps

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

They use dual Pi filter setup. Lousy design, but poly cap 10 u 100v costs more than 25 cent electrolytics, they have to cut cost to make sure the unit will fail after warranty runs out. I am sure there are hundreds more out there with same failure.

[Khron]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Embarrassing...

Yeah, 10u poly caps are expensive, not to mention huge Wonder what switching frequency the amp is at, though. Filter cutoff frequency seems to be around 3KHz, from what LTSpice is showing me.

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

The switching frequency has to be at least twice the highest frequency of the audio frequency you want to put out, so for sub woofer, the highest audio frequency will be about 300Hz or less.

[Khron]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

I'm starting to wonder how much sense Class-D makes, at quite such low frequencies, at least compared to good ol' Class-(A)B. At least dissipation-wise...

[tom66]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Far more efficient than Class-AB, and for high output power, costs much less. Some people think it doesn't work so well for high fidelity audio, but that is no fundamental limitation, just cheap amplifiers .

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

To get 200W with Class A/B the heat sink alone will cost a lot, will big heat sink. The Class D MOSFET's will be either fully on or fully off, very efficient but the golden ear people will never want to own one.

[jmbjr10]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

The caps (BI-POAR) and the Inductor are part of the output filter of the Class -D switching power amplifier. The Inductor is OK, the caps are the most common failure in these sub-woofer Class-D power amp.
Here is the Cap: http://www.mouser.com/ProductDetail/...EETKeRgSqTI%3d

Get extra.

I have replaced the caps with the ones you suggested and reinstalled the choke coil 35 uh ferrite core 25 I had. However, it still not working. Is it possible that they were not installed properly? I thought that the caps were bi-polar and it didn't matter how they were installed. I had the same feeling with the coil.Was I wrong? How should I check to see if the coil is bad? I'm new at this and I need someone such as yourself to help me. Thanks for your time.

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

They are non-polarized so it does not matter how you installed it, the choke has really large gauge wire and hard to damage it.
The purpose of the filter is to reduce the switching noise, it is more likely that the switching amplifier section is not working.
We need to do some voltage checking per diagram.
First, do you have sensing switch set to ON or Auto? If you have it set to auto, the amp will not turn on until it detects the audio input signals. I would set it to ON for now.
Do you see any indicator lights?
From the service manual:
"Move the Master Power Switch ª
(marked Power) to the “•” (On) position.
The SUB-TS14 subwoofer will automatically
turn itself on or go into Standby mode,
depending on whether or not a signal is
being sent to it by your receiver or surround
processor, and provided that the Music-
Sense On/Off Switch£is moved down
so that it is in the AUTO position.
When your receiver or amplifier is off, or is
not sending program material to the subwoofer,
the subwoofer will be in Standby
mode and the LED Indicator on the top
of the subwoofer will turn amber. When the
subwoofer senses an audio signal, it will automatically
turn itself on and the LED Indicator
will turn blue. If the subwoofer does not
sense a signal after approximately twenty
minutes, it will automatically go into Standby
mode.
When the Music-Sense On/Off Switch£
is switched to the ON position, the subwoofer
will remain on, whether or not program
material is playing, and the LED
Indicator will remain lit blue.
If you’ll be away from home for an extended
period of time, or if the subwoofer will not be
used, switch the Master Power Switchª
to the OFF position."

[jmbjr10]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

They are non-polarized so it does not matter how you installed it, the choke has really large gauge wire and hard to damage it.
The purpose of the filter is to reduce the switching noise, it is more likely that the switching amplifier section is not working.
We need to do some voltage checking per diagram.
First, do you have sensing switch set to ON or Auto? If you have it set to auto, the amp will not turn on until it detects the audio input signals. I would set it to ON for now.
Do you see any indicator lights?
From the service manual:
"Move the Master Power Switch ª
(marked Power) to the “•” (On) position.
The SUB-TS14 subwoofer will automatically
turn itself on or go into Standby mode,
depending on whether or not a signal is
being sent to it by your receiver or surround
processor, and provided that the Music-
Sense On/Off Switch£is moved down
so that it is in the AUTO position.
When your receiver or amplifier is off, or is
not sending program material to the subwoofer,
the subwoofer will be in Standby
mode and the LED Indicator on the top
of the subwoofer will turn amber. When the
subwoofer senses an audio signal, it will automatically
turn itself on and the LED Indicator
will turn blue. If the subwoofer does not
sense a signal after approximately twenty
minutes, it will automatically go into Standby
mode.
When the Music-Sense On/Off Switch£
is switched to the ON position, the subwoofer
will remain on, whether or not program
material is playing, and the LED
Indicator will remain lit blue.
If you'll be away from home for an extended
period of time, or if the subwoofer will not be
used, switch the Master Power Switchª
to the OFF position."

Thanks for everything I got it to work! I was wondering if I could ask you you another question? I still would like to know what could be the cause of the speaker acting as if it is over driving? It's not clear as it should be. It producing the base sounds well but it has sound like the speaker is being over driven. Any ideas?

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

What did you find out? May be you have to play with the frequency cutoff point and also the Phase. My JBL sub woofer will bottom out the cone if I set my freq. cutoff at 30Hz. Also if you set it at the corner of the wall, you will increase its output.

[jmbjr10]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

All I did was start the unit up with the woofer switch on to make the sub woofer stay on all the time. I got the blue light and the unit started to produce sound. I still need to work on the quality of the sound. I was looking at the posibility of recapping to help out with the clipping I believe I'm hearing. Since you seem to be very familiar with this Harmon/karmon Ts 14 woofer what should I be looking at to help out this problem? Thank You for all your help!

[dchu]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

I'm not sure what the rules are for reviving dead threads, and I apologize in advance for doing so.

However, I have the same sub-woofer, but a different problem. One day it was fine, then the next day I went to turn it on, it made a low buzzing noise. I disconnected all wires to the sub and turned it on so only power, nothing else, and it still made the sound. After that I took the back cover off and looked over the board. Nothing was burnt nor did anything explode, according to the various pictures I saw in the forums regarding bad capacitors.

I did however notice a brownish dried pool of I don't know near the 3 capacitors in the picture around the top. Also, is the yellow square at the bottom supposed to buzz when the sub is running? I think this may be causing the sound the speaker makes, but I can't say for sure.

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

I would suspect bad output filter caps like the two as shown in post1 to be bad since that is the common failure for this unit, it can also be bad main power supply filter caps.
Can you take good pictures of the boards and the top side of the two caps like the one on post1?