PB12/PB10 warranty 1year on amplifier? Does yours have a heat Sink?

Discussion in 'Archived Threads 2001-2004' started by Richard_s, Apr 30, 2002.

  1. Richard_s

    Richard_s Second Unit

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    I thought the PB12 had five (5) years until I read the warranty packaged with my new PB12 Subwoofer (same goes for the PB10).
    The case and Loudspeaker (the speaker itself) are warranted for 5 years but the electronics (AMPLIFIER) was limited to one (1) year.
    Those that own th JBL PB12/PB10 take a look at your warranty. Does yours limit the warranty on the amplifier to 1 year?
    Link to PB12 Specification details:
    http://www.jbl.com/home/products/pro...PB12&SerId=PBS
    This information in the link above states, if you look at the dimensions, that there is a HEAT SINK. Now my unit does not have one that I can see so Either I just got an early model or the heat sink is inside. Does your PB12/PB10 have a heat sink? If it does is it inside (you peeked) or outside the case?
     
  2. David_Stein

    David_Stein Second Unit

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    i have a pb10, i bought it with the nsp1 so consequently i cant tell the difference between the two warranty cards. however, one of the cards says that loudspeakers (including enclosures) are covered for 5 years. the other one says the loudspeakers (not including enclosures) are covered for 5 years, and that the enclosure is covered for 2 years
     
  3. Richard_s

    Richard_s Second Unit

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    When I got home I decided to open up the PB12 to give a look. A few things jump out at Me.
    Rant on
    1) I have not used the system since last night and the LED's were red. I unplugged the unit turned it over removed the speaker and I could find nothing that resembles a heat sink inside or out.
    2) If I were an owner of the PB12, which I am, I would turn off the unit when I was done using it. I touched the transformer and found that it was so hot that I could not hold my hand on it for more than a few seconds. Trust me that means in standby the transformer is running at 60 deg C. Also all of the electronics were hot (they are above the transformer so I could not tell if that was why they were hot). Remember this is after the system was in standby for 16hrs I unplugged it and it took me about five minutes to get inside to touch the transformer. I would love to see the circuit diagram for this unit (maybe this is typical for amplifiers in subwoofers). My guess is that they are using a switching power supply and to keep it regulating properly they have to keep load on the supply. Actually if it is a switching supply it probably runs cooler when one is using the subwoofer.
    Rant off
    For those with PB12's when your system is in idle does it feel just a little warm on the surface below the switch/power cord. Mine is just very slightly warm but inside it is HOT.
    The good thing is that I love the sound so for as long as that lasts I am happy with the PB12 but I will be turning it off at night when I remember. Can't put it on the receiver switched outputs they are not rated high enough maybe I will get a contactor (Relay) so I can use the receiver to turn off the subwoofer.
     
  4. Rick Guynn

    Rick Guynn Second Unit

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    The JBL units use digital amps. This makes them class D and they do not use heatsinks.

    The LED's *should* be red if you haven't used it for a while. They are supposed to turn green when it gets a signal and activated the circuitry.

    If you want a schematic, go look up my post on my PSWD-112 amp and follow the links to their service manual directory.
     
  5. Legairre

    Legairre Supporting Actor

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    I have 2 PSW-D112s and 2 PB10s. Both models came with a 1 year warrenty on the electronics and 5 years on the rest of the sub. Unlike everyone else with a PSW-D112. Both of mine have been problem free since I bought them 2 years ago. Both my PB10s amps went 11 months after I bought them. JBL replaced both subs with brand new ones.
     
  6. Rick Guynn

    Rick Guynn Second Unit

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    Legairre, be on the lookout.... 2 years was about where my PSWD-112 started messing up. I hope you have better luck. My solution thus far has been to buy a used plate amp and use that to drive the sub..
     
  7. Richard_s

    Richard_s Second Unit

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    Legairre: Thanks
    The PB10's that were replaced was there anything different about the NEW ones that I can use to tell If I have an early model or not. I just got my PB12 from Jandr last week. Someone said the "Revised/New" models have a power switch and the "early" models did not is this correct or is there some other way to tell what Vintage I have. Also did you always leave your unit in standby or turn them off when not in use?
    Rick: Thanks
    Using an external AMP was my back-up plan after warranty if I have a problem. Where do you get such amps (who knows maybe I will become a DIY). I am interested right now on how much they cost. YES the light turns RED but like I said above my amplifier area was very hot (inside) and stays warm on the outside during standby, would you expect this from your experience with the JBL sub's?
    Found the post and got the manuals thanks for the link.
    All comments?
    The manual states that the "standby power" is 26watt that would explain why the power transformer is running so hot this is a high standby power. I will contradict myself now. I would guess that leaving the PB12 in standby even though it is keeping the amplifier quite warm is better for reliability than turning it off when not in use. This would help limit temperature cycling and power surges to the electronics on turn on and this minimizes stress to the electronics. This is consistent with JBL recommendation that standby be used in general and the unit should be turned off when you are on vacation or some other longer term not in use state. BTW 60 deg C is not hot for electronics.
    The manual further states that the 250W amplifier is 65% efficient. Seems to me like some heatsinking is needed especially when KILLER bass sountracks are run. For normal everyday usage the average power is probably low enough @65% efficiency to get away without a heat sink.
    EDIT: Link to the JBL manuals from Rick's post:
    http://manuals.harman.com/JBL/HOM/Service%20Manual/
     
  8. Rick Guynn

    Rick Guynn Second Unit

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    Richard, I bought my amp from a fellow HTF'er who posted them for sale in the Hardware forsale section here on the forum. Also be on the lookout for specials from MCM and Parts Express. PE just had an outstanding deal on their 250W plate amp (which I bought for an upcoming IB project).

    What I did was make an enclosure for the plate amp and just 'plugged' it in to the sub. I modified the speaker-level inputs on the exisiting amp in the box such thast the driver leads were now wired into them. That way, I can either plug the external amp into the driver, or jumper the built-in amp to it for when I finally get around to trying to troubleshoot it...

    Rick
     
  9. Legairre

    Legairre Supporting Actor

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  10. Richard_s

    Richard_s Second Unit

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    Legairre

    Hope I never have a problem but it is a good heads up that maybe they would be willing to let me swap out the amp myself. I wonder what they get for a replacement amp if mine goes after the warranty is up?

    I really like my PB12 it seems very tight and blends extremely well with the "N" series JBL speakers that I have. I will take my chances with the reliability issue.
     

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