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    #1

    Smoke alarm caps bad. Can anyone identify please?

    Hello all,
    I have a problem with my mains wired smoke alarms. This is actually fairly worrying as our lives could depend on these! There are 5 capacitors in each alarm but they seem to have no proper identification on them. This may of course be to stop people replacing them instead of replacing the whole unit, a safety measure I guess. So my questions are 1) can anyone identify these for me? 2) is it safe for me to do so seeing as how important it is that these alarms work properly. I have replaced many caps over the last year or two and have a basic knowledge of electronics so it is not my ability I am questioning but rather the safety aspect. I am in the UK so the units run on 230volts.




    Any help appreciated.

    Ian.
    Last edited by GrumpyOldMan; 01-25-2009, 06:42 AM. Reason: Spelling mistake.
    Tags: None
    #2
    Re: Smoke alarm caps bad. Can anyone identify please?

    Looks like Panasonic made caps with the "M" inside the square symbol. They are supposed to be high quality Japanese caps. I've never seen them fail personally, but I suppose the smoke alarm unit isn't well ventilated and runs hot which has caused this issue.

    Are the vents on the of the caps a "T" shape?
    Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

    Comment

      #3
      Re: Smoke alarm caps bad. Can anyone identify please?

      Originally posted by stevo1210
      Are the vents on the of the caps a "T" shape?
      Hello Stevo. Thanks for replying. Yes they are a T shape. I myself thought they looked a little like Panasonics but there are no real identification marks on them, just what you see in the pics. They are 9 years old by the way.
      The one in the picture is the first one to go and is at the top of the house, that could mean it's in the coolest part of the house as it's just under the roof. But of course heat rises so maybe it's the warmest part of the house.
      Cheers,
      Ian.

      Comment

        #4
        Re: Smoke alarm caps bad. Can anyone identify please?

        I'd be wary of fixing them
        If some problems crop up you could be liable...
        I would only fix them if I had a license to do so
        "The one who says it cannot be done should never interrupt the one who is doing it."

        Comment

          #5
          Re: Smoke alarm caps bad. Can anyone identify please?

          Originally posted by Per Hansson
          I'd be wary of fixing them
          If some problems crop up you could be liable...
          I would only fix them if I had a license to do so
          Very good point, thanks. That's the answer to my question 2. The alarms were fitted when we had the loft converted to a room and were part of the specifications for the local building regulations.
          I am considering contacting the supplier though as I feel this is an important issue, not that they can do much about it I suppose.
          I would still like to know what they are though if anyone can identify them. My brother in law IS a qualified electronics engineer so he could fit them for me. I will be giving it to him to have a look at anyway so he can probably identify them if it is possible to do so. Won't be seeing him fo a while though and can save time if I can obtain the caps first.
          Thanks again,
          Ian.

          Comment

            #6
            Re: Smoke alarm caps bad. Can anyone identify please?

            My earlier post seems to have gone *poof*.

            They are Matsushita/Panasonic. [That M is their logo.]
            There should also be a "T" shape stamped in the top with the top bar of the T being curved such that the outter ends are higher than the center. [Loosely reminiscent of a steer's horns.]

            Good brand.
            Most likely died due to a power surge or a bad design (heat).

            You aren't showing the side with the series marking.
            It should be two letters on those.

            .
            Mann-Made Global Warming.
            - We should be more concerned about the Intellectual Climate.
            -
            Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
            - Dr Seuss
            -
            You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
            -

            Comment

              #7
              Re: Smoke alarm caps bad. Can anyone identify please?

              Oooops.
              On closer inspection I found this.

              Sorry. They were quite well hidden though!

              Ian.
              Last edited by GrumpyOldMan; 01-25-2009, 10:19 AM. Reason: poor layout.

              Comment

                #8
                Re: Smoke alarm caps bad. Can anyone identify please?

                i believe thats a capacitor "battery" for when the mains supply is off
                capacitor lab yachtmati techmati

                Comment

                  #9
                  Re: Smoke alarm caps bad. Can anyone identify please?

                  Yes, that is exactly what they are.

                  I've just priced them up though and it will cost less to buy some new alarms!

                  Thanks for everyones help and input though.

                  Ian.

                  Comment

                    #10
                    Re: Smoke alarm caps bad. Can anyone identify please?

                    yes EECA0EL106 is at the rather piss taking price of £4.81 each at RS
                    capacitor lab yachtmati techmati

                    Comment

                      #11
                      Re: Smoke alarm caps bad. Can anyone identify please?

                      In that case I would install a battery holder and a real rechargeable battery.
                      [Or just get new detectors.]
                      Mann-Made Global Warming.
                      - We should be more concerned about the Intellectual Climate.
                      -
                      Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                      - Dr Seuss
                      -
                      You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                      -

                      Comment

                        #12
                        Re: Smoke alarm caps bad. Can anyone identify please?

                        Originally posted by PCBONEZ
                        In that case I would install a battery holder and a real rechargeable battery.
                        Could I do that? Presumably it would have to be a 12v battery or would 9v do? What other changes, if any, would I need to make?
                        To be honest though I can get a direct replacement mains smoke alarm with battery backup for under £12.00 so it's probably worth doing that just to save all the hassle although I do relish a challenge! (A mains alarm with capacitor backup however is about £36.00, which is why I originally thought replacing the caps might be a good idea).

                        Cheers,
                        Ian.

                        Comment

                          #13
                          Re: Smoke alarm caps bad. Can anyone identify please?

                          Originally posted by willawake
                          yes EECA0EL106 is at the rather piss taking price of £4.81 each at RS
                          If I bought 15 from Farnell they would be £2.72 each + VAT (3.61 + vat for 1). I have 3 alarms so I would need 15. Still quite expensive though and they could possibly go again anyway.

                          Ian.

                          Comment

                            #14
                            Re: Smoke alarm caps bad. Can anyone identify please?

                            i bet the voltage went high.
                            first time i have ever seen these fail.
                            those are a "battery"
                            they float on the supply and hold it up if the ac fails.

                            Comment

                              #15
                              Re: Smoke alarm caps bad. Can anyone identify please?

                              Yes it would work if you can get the voltage right. Would want battery voltage to be a bit higher than Circuit voltage so they never over-charge. Should check circuit voltage with a meter.

                              I'm not sure which of LI, NiMH, or NiCAD would be best for that. (Or if it matters.)
                              - kc8adu or linuxguru might know. One or both of them dabble in that area.

                              Even still the mod may be more expensive than just replacing the units.

                              .
                              Mann-Made Global Warming.
                              - We should be more concerned about the Intellectual Climate.
                              -
                              Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                              - Dr Seuss
                              -
                              You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                              -

                              Comment

                                #16
                                Re: Smoke alarm caps bad. Can anyone identify please?

                                Since electrolytic double layer capacitors (supercaps) have a lifetime rating of around 1000 hours, I would not recommend them for this application.
                                Instead, a Ni-MH (no memory effect) rechargable battery should be used.
                                My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

                                Comment

                                  #17
                                  Re: Smoke alarm caps bad. Can anyone identify please?

                                  Is it even worth fixing? I believe yours is close to the end of its life anyway. They won't last forever.

                                  Here's a quote from the U.S. Environmental Protection Agency:

                                  "Regardless of the detection technology used in your smoke alarm, the product label, User's Manual or Warranty should state the expected useful life of the smoke detector. For example, smoke alarms with the UL label have been certified with an expected useful life of 10 years."

                                  http://www.epa.gov/radiation/sources/smoke_alarm.html
                                  Last edited by mutant; 01-26-2009, 01:00 AM. Reason: misspelled words

                                  Comment

                                    #18
                                    Re: Smoke alarm caps bad. Can anyone identify please?

                                    That's because of the half life of the radioactive source they use.
                                    It gets weaker over time.

                                    Thing is when the source goes bad they will keep going off (alarming.) so it's pretty obvious time is up.

                                    .
                                    Mann-Made Global Warming.
                                    - We should be more concerned about the Intellectual Climate.
                                    -
                                    Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                                    - Dr Seuss
                                    -
                                    You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                    -

                                    Comment

                                      #19
                                      Re: Smoke alarm caps bad. Can anyone identify please?

                                      Did my post get deleted???

                                      Comment

                                        #20
                                        Re: Smoke alarm caps bad. Can anyone identify please?

                                        No just ate by the internet.
                                        One of my posts did that yesterday.
                                        Mann-Made Global Warming.
                                        - We should be more concerned about the Intellectual Climate.
                                        -
                                        Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                                        - Dr Seuss
                                        -
                                        You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                        -

                                        Comment

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