No sound out of the sub. the rest of the sp. work fine

SOURCE: Sony Home Stereo Fuse

When the wires touched, the output transistors overloaded before the fuse had a chance to blow. The outputs need to be changed. It is possible that the driver stage for the final outputs is bad also, but there is no way to know that without removing the bad outputs. Figure on $25-$45 in parts for this repair.

Dan

SOURCE: Philips Home Theatre System - no sound or power light on sub woof

reset the device to factory settings, it is written in your manual how to do this. If that doesnot work, unplug the powersocket for about 30minutes, it will cause an internal reset which might solve it.

Edgar

SOURCE: bose acoustimass 25 subwoofer has no power

Honestly speaking you should probably not work on this unit yourself: "There are no user serviceable parts inside"

Even if you are an accomplished Electrical Engineer Bose will not provide the required schematics to troubleshoot and repair this unit.

Are you still undaunted . . . then if the case is the original LS-25 series, there is a hidden catch at the end of the cover furthest from the input connectors that needs to be rotated (until a plastic tab is sticking out), which you can do with a flat bladed screw driver, and you also need to remove a few screws from the bay where all of the connectors reside. Remove the two knobs from the side of the cover. Then hit the case with your fist at the far end (plastic tab) and the cover should then pop off. You may have to hit it hard, with an upward motion.

Note there is not going to be much you can do to fix this beyond replacing the fuse. (Note that the fuse may be soldered in.) The bass amplifier is op-amp based with discrete class G output stage and the twiddler amps are monolithics with discrete class G circuitry shared between several channels.

The power transformer has a thermal fuse in it as well which is not replaceable. If you play the unit loudly for long periods of time and it is not adequately ventilated it is possible for the thermal fuse to open - if this is the case you will definitely need to send it in for service.

When plugged in there are hazardous voltages present on the top PC board where the power connector is located, whether or not the unit is turned on.

Power switching is via a triac controlled by whichever front end you have CD-5? 12V should be present on the mini plug (tip I think, but might be ring) when the music center is on.

There is also offset detection circuitry that will latch the unit off should any output have more than a volt or so of offset.

For more information see following web site:

http://www.diyaudio.com/forums/showthread/t-106135.html

SOURCE: Just got JVC SP-PWC50 subwoofer and 2 SP-THC60F

Your intended project sounds interesting. I like the idea of retasking older audio gear into modern multichannel sets. One good reason to use older equipment is that the specs, interfaces and interoperability are standardized so you can tell if/how a given amp and speaker will work together. I do it myself.

It looks to me like you have only part of an HTIB (Home Theater In a Box) system that uses a proprietary 8-pin connector and system cord that would come from the base unit/DVD/receiver (the 'brains', which you don't have). It doesn't appear to be designed for compatibility with other units, say, something that would bring in the 5.1 channel audio via either a digital (SPDIF) cable or via 5 separate RCA audio cables.

This subwoofer is self-powered and also provides amplification to up to 5 other speakers, two of which you have.

Their connection to the sub would be via standard speaker cables, likely the Red and White FRONT spring clips. The output terminals are rated up to 16 ohms so attaching a foreign speaker should not be a problem other than its having unpredictable frequency response.

Besides basic connection and signal processing, the missing DVD/Receiver would also decode and direct the 5.1 channels to the Sub and handle level matching of the channels. Without the 'brains' of the system you'll have to get creative to use the individual parts. The 8-pin input connection will be a big problem unless you're adept at getting inside the unit to figure out where things go before they come out at the speaker terminals. Then you'd have to do some rewiring.

UNDERSTAND THIS: Those connectors are OUTPUTS to speakers, not inputs from an Amplifier. If you hook that up wrong you better have a fire extinguisher handy. Kidding. But it could be bad.

The Front speakers are 3 ohm impedance, clearly designed to be used with the amps inside the Sub so I would be careful in trying to drive them with amps that aren't good at handling low impedances. Give it a try AFTER checking the low impedance tolerance of your amplifiers, but easy on the volume.

I would not expect all of this to be a worthwhile effort unless you just like the challenge. Even if you succeed in making a satisfactory electrical connection with your multichannel source as input there is no way to know if it will sound okay. With all-in-one systems the manufacturer may have matched the speakers up with special amplifiers that are designed for 3-ohm speakers and to shape the sound through active internal equalization in such a way as to produce flat response from non-flat-responding speakers - like Bose does, for example, but at least they tell you that's the case.

The stated spec is 200 watts (RMS) per channel at 3 ohms at 100Hz with 10% Total Harmonic Distortion, a very unusable spec. True and honest watts/channel specs look like, "XX CONTINUOUS watts per channel, all channels driven into 8 ohms (20 Hz - 20 kHz, +0.5 dB, -3 dB less than 0.5 percent THD)".

At only 27 lbs with a Power Consumption of only 160 Watts I'd say the Amps/Sub component of the package is a lightweight, literally and figuratively. Apples and oranges when compared to grown-up audio components. It might get loud but not cleanly. But that's just my opinion.

Here's the Owner's Manual for the entire kit...
http://akamaipix.crutchfield.com/Manuals/257/257THC50.PDF

There's some discussion of the features, etc, here...

http://www.crutchfield.com/p_257THC50/JVC-TH-C50.html?tp=195&tab=detailed_info

SOURCE: NO SOUND From JVC TH-S5 Home cinema system

I know this is an old topic however someone somewhere might benefit from this feedback. I purchased the JVC TH-S5 service manuals from ManualsParadise.com and after metering all the supplies as 'OK', I then focused in on the 'common' lines associated with the two onboard power amps IC's (STK413-400) and found that they were missing a bias supply. This is derived from the onboard 40v Supply 'dropped' down by a 47 ohm resistor R2702 (rated 1/4 watt but advised to make this at least 1/2 watt). The resistor was found to be open circuit i.e. a very high ohmic value. Looking at the circuit diagram again, I would feel that this is going to be a common issue with this unit.

Mike.The.Cork