Troubleshooting Harman Kardon TS-14 Subwoofer

[romeo_morano]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Hi there, newbie here.
I have an HKTS11 sub, and recently I noticed a low humming sound even without audio signal introduced in to the sub-woofer.

Further, connecting some wires on the input, I noticed that the sub receives some FM radio station signal.

Anyway, that FM signal can be eliminated. I am more concern on the humming produced by the sub. Reading on the posts above, I am little bit skeptical if the output filter caps would cause the hum, also the said output filter caps do not show any sign of physical damage. I checked the power supply filter caps (4,700uF/80V x 2) and find it still fine/ok.

Any suggestion how to proceed with my troubleshooting will be highly appreciated. TIA

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Is the hum there when the there is no connections to any of the input jacks? We need to find out if it is power supply filtering problems or ground loop problems.
"I checked the power supply filter caps (4,700uF/80V x 2) and find it still fine/ok." How did you figure out if they are good or not? Did you check the ripple voltages?

[romeo_morano]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Hi budm, the hum is there even if no connections to any input jacks.
I checked the filter capacitors using analog tester. Where, upon touching the test probes (multi-tester is set to x10Ohm) to both terminals of the capacitor, the pointer of the meter goes to the mid-section and slowly moves to right (or infinity).
With regards to ripple voltage, I cannot check them as I don't have an oscilloscope.
Thanks..

[stj]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

i have done loads of harmon champagne/soundstix stuff, i will just say that the caps in them are junk.
8 out of 10 problems are fixed just by recapping them with panasonic FR's

HK may be an expensive brand, but they use the worst caps!

btw, if it uses a switching psu, those often need a recap too - and dont use chinese replacements from ebay.

[budm]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Hi budm, the hum is there even if no connections to any input jacks.
I checked the filter capacitors using analog tester. Where, upon touching the test probes (multi-tester is set to x10Ohm) to both terminals of the capacitor, the pointer of the meter goes to the mid-section and slowly moves to right (or infinity).
With regards to ripple voltage, I cannot check them as I don't have an oscilloscope.
Thanks..

Testing cap with that method does not tell you the capacitance of the cap.

[betula]

Re: Troubleshooting Harman Kardon TS-14 Subwoofer

Newbie? yes, guilty as charged. Old thread, yes, I know. I have one of these with the same problem. Does anyone have a lead for schematics for this unit. And oh, ya....does anyone know where that adhesive comes from? All three pub's have it in different colours.