Question about Audio Players & Recorders

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Posted by CLIFF N on

  • 8 more comments 
  • CLIFF N Nov 01, 2011

    SUB is a boston acoustics..Lost any ideas???????????????

  • Shawn C Nov 27, 2011

    I have same sub, same problem. Fuse is good but unit will not power up. I took back plate off and examined for any burn but nothing. I have no idea????

  • Shawn C Jan 12, 2012

    Thank you Jason that was the problem, I assumed the the burn was excess glue. I am an electrician but somewhat unfamiliar with soldering such small components. Do you have any tips for removing solder, and is there any specific solder to use or is a flux?? needed?
    Thanks again!

  • toyota4747
    toyota4747 Jan 31, 2012

    just repaired this same power supply and mine had a metalized film capacitor failure. Part labeled as c27 on board. Available at radio shack as 272-1053 or .1uf 250volt.

  • Sebastian Videtto Feb 06, 2012

    The solution worked like a charm, THANK YOU.... mine failed a few months after the warranty expired, so I was already looking at a new unit to replace mine... $2,49 for 10 diodes for the fix.
    Thanks Again!

  • Jason Pullin Feb 08, 2012

    The best thing to use to remove solder without using a high dollar 'solder ******' is solder wick. Solder wick is basically a woven copper that conducts heat very well and will heat the solder to melting, after applying a soldering iron, and just soak the liquified solder up.
    As far a flux is concerned most electronic solder has flux in it and there is no need to buy flux seperately. Unless you are soldering military grade or nuclear grade electronics, then due to qualification standards you would have to use a higher silver grade solder with less flux.

  • vman Feb 25, 2012

    I opened it up and I believe in my case the issue is component labeled ZD3 - the entire area around it is blackened and burned. I desoldered it but now have no idea what the actual part is - any clues (I suspect it's a zener diode, but not sure what the specs are)

  • vman Feb 25, 2012

    I opened it up and I believe in my case the issue is component labeled ZD3 - the entire area around it is blackened and burned. I desoldered it but now have no idea what the actual part is - any clues (I suspect it's a zener diode, but not sure what the specs are)

  • Samuel Mills May 31, 2013

    Hi, guys. This is NOT a standard switching diode. It is an ~18V Zener Diode. Inspecting the part with a jeweler's loupe gives the part number Z18B, which is actually approximately a 17V Zener, but 18's are more common and should be fine. Replacing this with a standard switching diode might make the unit work temporarily. The problem is that when it fails again, it isn't just going to be the's going to cook that tiny surface-mount PWM circuit, and you're going to be up the creek.

  • Alex Jun 28, 2013

    Samuel, do you have the entire spec on that diode ? I have the same problem, and as far as I can see a couple of capacitors are leaking, those I manage to gen my hands on new ones (spec is printed aroud the capacitor) but the diode is a hard one to bite... I can imagine it should be a 17.955 or so Zener Diode, how bout V and tolerance ? what brand is the original diode ? Thanx in advance for any comments



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Jason Pullin

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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

  • 19 more comments 
  • Shawn C Jan 13, 2012

    I meant to post above comment here

  • Shawn C Jan 20, 2012

    So I replaced diode as directed. Now when I turn sub on I get a green LED regardless of whether it is connected to receiver or not. Still no sound, and the green LED sort of flutters, it is not a steady green light. Any ideas or suggestions?

  • Jason Pullin Feb 08, 2012

    Shawn check and maker sure your diode is not in backwards.

  • Jason Pullin Feb 08, 2012

    Also make sure you did not inadvertently install a zener.

  • Jason Pullin Feb 08, 2012

    Another quick check could be to test the diod by using your meter. Otherwise it sounds as if it could be a SCR (gating diode) which basically takes an AC voltage and gates a DC voltage off of it. These can sometimes be used to power indication lights. This should be on the power board. Just know I am totally bench top troubleshooting and I have no schematics because I could not get Boston to give those up to me.

  • Jason Pullin Feb 08, 2012

    By the way sometimes this type of SCR is refered to as a Voltage Regulator.

  • Jason Pullin Feb 29, 2012

    Vman sound like a zener. Look for clues on the board such as a zener symbol. Go to this link to learn more.

  • Loganmac May 12, 2012

    Did this fix it because I'm having the exact issue as Shawn diode and fuse. Green light now but no sound!

  • Loganmac May 12, 2012

    I'm having the same issue a Shawn r/r fuse and diode put it in the same way as the line. But have green fluttering light no sound now..

  • Loganmac May 13, 2012

    Well tried the Zener for s and giggles. I can't find the scr diode I'm lost!

  • Chris Duhe Jul 06, 2012

    I recently replaced the diode as well according the posted directions, and I am having the same issue as described now as well .. (Green fluttering led with no sound..) I find it really interesting that all the other diodes on the Circuit board are labeled D01,D02, etc.. then the bad diode which is labeled ZD3.. hmm I'm thinking that was a Zener Diode.. which would be appropriate for a system that has a 180 degree polarity switching.
    Who here has had success with this radio shack diode replacement??

  • JayB Apr 21, 2013

    Thanks so much. Just tried this and it worked. The Radio shack part comes in a package of 10. The diode is different looking than the original. The black band of the diode is part the way the electricity flows. On the board it has a little arrow that shows which way to put it in. Pretty easy and the first time I ever soldered a board like this. Thanks again.

  • Samuel Mills May 31, 2013

    Hi, everyone. Part ZD3 was bad in one of these units, which I just repaired for a customer. Unlike the other cases, here, this one wasn't blackened or burned, so I got out my jeweler's loupe and read the part number printed on the glass body: Z18B, which is an 18-volt zener diode. Replacing the part with a standard diode is NOT safe...the diode won't avalanche at the right voltage, and when it DOES avalanche, it will fry the part and kill the unit, again. Popped in an 18V zener and it was good to go.

  • Erik Nissen Jun 07, 2013 This is the replacement part for zd3

  • Kawa
    Kawa May 29, 2014

    I Hello, so I replaced the zener diode on my unit that wouldn't power on but I had no luck in getting it to power up. I check what I could with a multimeter. Not really sure what to try next. Any ideas?

  • Jniwen
    Jniwen Aug 14, 2014

    hi guys i replaced the zener diode as well as 140k 250 kc capacitor ( 2 nos) as well , mine is working now.

  • CJ Hawkins
    CJ Hawkins Jan 25, 2015

    So this 140k 250 kc capacitor (2 nos) where is this located???

  • Kenneth Pullin
    Kenneth Pullin Jan 31, 2015

    mine just died...thanks for the good luck boys! LMAO!! mine torched a metal film cap on the right side of that the cap the one guy spoke of?

  • Kenneth Pullin
    Kenneth Pullin Jan 31, 2015

    plus the zener....i think the cap is what killed the zener......all owners beware!!! mine did it in the MIDDLE OF THE NIGHT on standby!! was on FIRE! (temporarily of course)

  • CJ Hawkins
    CJ Hawkins Feb 06, 2015

    OK. I found two ceramic capacitors which are blue side by side that were blown. Board glue was hiding the visible damage. I know Radio shack is going bankrupt but, here is the part # 272-1053. Replaced both and the zener diode discussed above and sub is thumping again..

  • Jaret Choquette
    Jaret Choquette Sep 23, 2015

    Does anyone have the part # for the correct 18v 0.5w Zener diode? Thanks in advance. I'm trying to fix my roommates sub after my brother decided to unplug it while playing (and it wont come back on).



1 Related Answer


Michael Edwards

  • 60 Answers

SOURCE: Describe your Venue SUB10 Subwoofer

You can remove the screw near the volume knob and the screw near the on/off switch - then slide out the amp remove the black and white wire - then check the fuse - if its blown look for we repair amps - ebay - if its good then it probably still needs work - it should turn red when plugged in and no signal and green when signal is present - which means amp is on.

Posted on Nov 03, 2011


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