Question about Denon Audio Players & Recorders
I had the same problem with my subwoofer unit. I found the zener diode ZD3 was fried. The pic below shows the diode and its clearly tagged ZD3. You need a multimeter to check this before you order anything. This diode should only transmit power in one direction. Its size and spec is 18v .5w zener diode. (that's 1/2 w) It's very inexpensive and the whole repair took about an hour. This is from a Boston Acoustics subwoofer MCS 160
Ok..the procedure is easy.
1) unplug the unit and bring it to a well lit work area.
2) remove the panel from the back and locate the board that is held to the panel by 4 screws and has the ZD3 diode. The pic below shows the diode at the end of my test lead. Note the direction of this part and reinstall the new one in the same direction. Its a simple de-solder and re-solder project. I elevated the new diode about 1/8 " from the board with a small strip of copper. This acted as a heat sink during the soldering and elevated the part above the board to help it dissipate heat later when in use.
3) re-install the board and plug in all the connections.
4) this worked for me and I'm enjoying my sound system again!..good luck
Posted on Feb 26, 2014
This fixed mine!! Saved me a ton of $$. Got 20 of the diodes on eBay for $6. Nice job!
Posted on Feb 04, 2016
Concerning the Boston Suwoofer not powering up, I just had the same problem and this is what I did to fix it.
1. Uplug the unit
2. Remove the outer screws and remove the board unit
3. Unplug the board (Power Board) that is connected to the switch and unplug the two connectors that connect to the amp.
4. Remove the 4 screws(on the front panel side not the nuts on the board)
5. Look at the switching diode (labeled #1) directly beside the transistor cooling plate, if the board around this transistor is burnt there is a good chance that the diode is fried. If you do not trust your eye you can measure across the positive and negitave of the diode with your multi-meter (on the diode check setting) and you should read ~.565 and you should read infinity if you swap the leads. If the diode reads ~.667 and you can read this taken across any polarity the switching diode is fried.
6. If the diode is fried go to radio shack
7. Purchase a 1N914-1N4148 Switching Diode. Cost about $1.36.
8. Go home de-solder the fried diode.
9. Solder in the new Diode. ***Pay ATTENTION to put the new diode in the exact way the old one came out!!*** If you do not get the polarity correct the diode will not work properly and your unit will not power up. Also, it is a good idea to leave ~ 1/8" between the diode and the board, this will help disipate heat the cause of the problem to begin with.
10. Place power Board back on the backside of the front panel
11. Install 4 screws(on the front panel side not the nuts on the board)
12. Plug the board (Power Board) that is connected to the switch and plug the two connectors that connect to the amp.
13. Place the panel back onto the subwoofer and secure it with the screws. You can use a screw gun for this just make sure to turn you tourqe level back to ~3 otherwise you could strip out the screw and or the particle board.
14. Plug it in and your rolling.
I hope I am not to late and this works out for you. I just fixed mine tonight.
Posted on Jan 08, 2012
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