Question about Bosch Audio Players & Recorders
yeah you can fix that one into your own. first thing that you do is get a multi-tester and put the two terminal the red one and the black into the tip of male plug of you wire. then set your multi tester into the ohms selector any ohm selector which found at the right side of the multi-tester. if the arm of multi-tester was moving it means OK... if not open the speaker carefully and reconnect the wire by using soldering iron & lead.
Posted on Nov 06, 2007
SOURCE: The bass speaker doesnt work
OK, Bose owners out there listen up and
listen good. Here's the real scoop on 1.(getting access to the inside of most
bose subwoofers, 2.( repairing said subwoofer.
Follow these steps in removing the cover of your subwoofer. Unscrew the two screws from the cover. (They are on the input/output side of the cover) Remove the two knobs (Bass and treble volume).
On the opposite side of the cover, (put those damn shoes back in the closet) there is a lockout tab that needs to be swung out, it moves 90 degrees in a counter-clockwise direction and is located under the center of the cover.
A small flat blade screwdriver works great for swinging this tab out and will be necessary for the next step (the screwdriver that is).
On the same side (opposite the input/output side) there are two small tabs near the edges of the cover, one on the right and it's counterpart on the left. If you look closely in the gap between the cover and the sub itself, you will see these 3/8" wide tabs near the edges and towards the top of the cover.
With the flat blade screwdriver, put the blade between the cover and on the tab and pull down. Then with your hand balled into a fist, gently hit that side of the cover towards the input/output side. the cover will move only slightly but the tab should remain depressed.
Do the same procedure on the opposite side of the cover and it will slide about a 1/2 to 3/4" towards the input/output side and can then be removed by pulling it straight up and off of the cabinet.
Yay! If you get this far without incident then you are ready to implement repairs. In the case of the AM15's, normally what happens is a resistor will open up and prevent the triac (turn-on device) from firing.
The fuse is on the underside of the PC board and this above mentioned resistor is a 100 ohm, surface mount "chip" resistor on the top side of the PC board. It will not appear to be bad but trust me, if the fuse is good and the sub will not turn on... replace it!
You don't have to use a chip resistor since as a consumer you may have a rough time finding one but a 1/8 watt or 1/4 watt resistor you can find at any Radio Shack will work just dandy in this application.
Cut the leads short and solder the two cut leads to the pads on the circuit board where the chip resistor is currently sitting. The chip resistor will be black, about 1/4" long, 1/8" wide and have "101" printed on it's surface. On some models they used two 200 ohm resistors in parallel but the result is the same. One 1/4w axial lead resistor will do just fine. Plug it up and give it a try. (Before you replace the cover).
Secondly, if the fuse is blown on a "Lifestyle" Bose subwoofer, contrary to popular belief, it blew for a reason. The speaker outputs and the subwoofer output devices are TDA7294 IC's with TIP142 and TIP147 Motorola transistors used as current supplements to these said output devices. If the fuse is blown and replacing it only results in another blown fuse then chances are good that one or more of these are blown. In some cases it's very easy to tell, the front of these IC's will be blown off and/or you will see burn marks on the board where they are mounted. These devices are located inside the amp portion of the subwoofer. (The black metal heatsink underneath the input/preamp PCB. As a consumer, if the fuse is blown, unless you are familiar with soldering techniques and troubleshooting electronics, leave this to the pro's. It isn't as easy as you might think and you can destroy the PCB in your attempts to repair it.
This was from a Guru of Bose systems at ecoustics.com: Mark Burgess
Posted on May 11, 2008
SOURCE: Fried Woofer
The problem are worsen that before. It is wisely to replace both left and right amplifier
IC, but make ensure that the power supply feed a good amount of voltage to amplifier,
Also a strong good signal. Be sure to measure it.
Posted on Nov 29, 2008
The Denon 2500 was one of the best ProLogic receivers built, it was a work horse and very little ever went wrong with them.
To make sure you're only supposed to hear right & left speakers, press the Stereo button on the remote. Also recheck your speaker connections - this is the single most overlooked connection problem folks have.
Check the balance control to make sure it's in the center position
Make sure the Tape Monitor is not engaged.
Then, check to make sure that the Pre-Out, Main-In jumpers are connected properly on the rear panel.
If that is not the problem, try pressing the Tone Direct button on the remote (aka Tone Defeat on the front panel).
Posted on Oct 22, 2009
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