Another BM4400

Viewing 12 posts - 1 through 12 (of 12 total)
  • Author
    Posts
  • #31951
    hcraig244
    SILVER Member
      • Topics Started 7
      • Total Posts 189

      Ok….I’ve had this amp floating around for a few years now on the “around 2 it” bench and finally had a look at it….naturally it doesn’t work. At least not completely….one channel is very eratic, switches are not happy and the overload lamp flickers on and off intermittently.

       

      #31953
      hcraig244
      SILVER Member
        • Topics Started 7
        • Total Posts 189

        A look inside gives a clue to its woes…..P1017183

        #31955
        hcraig244
        SILVER Member
          • Topics Started 7
          • Total Posts 189

          cobwebs everywhere…..P1017186

          #31956
          hcraig244
          SILVER Member
            • Topics Started 7
            • Total Posts 189

            underside look pretty clean howeverP1017187

            #31962
            hcraig244
            SILVER Member
              • Topics Started 7
              • Total Posts 189

              dusted away most o the debis and gave all the switches a blow over with de oxit and left them to soak…..did spot this….looks like a broken trackP1017193

              #31965
              hcraig244
              SILVER Member
                • Topics Started 7
                • Total Posts 189

                left the deoxit to dry off and had another go…switches all operate much better, tried FM works fine both channels….so does the phono input, got it on test or the day see how it performs, the suspect broken track will need some attention/investigation for sure…nothing is getting hot right now…..so Dillen can I have a capacitor kit please? it’s easier for me to buy from you that trawl the component websites ;¬)

                #31969
                Dillen
                Moderator
                  • Topics Started 3
                  • Total Posts 587

                  Service kit etc. here.
                  And it looks a very nice project.
                  They are definitely worth it.

                  Well spotted, that break!

                  Martin

                  #31997
                  chartz
                  GOLD Member
                    • Burgundy
                    • Topics Started 3
                    • Total Posts 213

                    Hi,

                    Entirely worth the efforts. Mine has been to service every single day since its repair 10 years ago. The other day we went out for a few days, the 4400 had been left on. No problem at all. Once restored properly the 4400 is reliable and above all, sounds mighty fine. Mine feeds M70s in the lounge.

                    #32006
                    hcraig244
                    SILVER Member
                      • Topics Started 7
                      • Total Posts 189

                      discovered the individual responsible for the cobwebs…at least some of them i’m sure…..P1017194

                      #32007
                      hcraig244
                      SILVER Member
                        • Topics Started 7
                        • Total Posts 189

                        disconnected plug P11 and with the help o a little piece of wire connected to r168 220 ohm resistor and gave the suspect track break several hard pokes with a blunt stick, reading never budged…..so as I cant see the underside of the board im going to give it the benefit of the doubt for now….im considering running a piece of wire topside just in case….P1017195

                        #32565
                        hcraig244
                        SILVER Member
                          • Topics Started 7
                          • Total Posts 189

                          Received this little lot in the post a couple of days ago…..

                          P1017201

                           

                          #32566
                          hcraig244
                          SILVER Member
                            • Topics Started 7
                            • Total Posts 189

                            Cheers Martin…….buying one of your kits is by far the best way to obtain the necessary parts for a refurb…I’ve tried buying parts myself and although it can be done I ended up placing orders with multiple suppliers to purchase all the parts….and in some cases there is a minimum order level….so you end up with 5 trim pots of a particular value when you only need 1…..and of course the big output capacitors in the kit are custom made to be the correct diameter to replace those made back in the 1970’s……good job Martin ;¬)

                            Craig

                          Viewing 12 posts - 1 through 12 (of 12 total)
                          • You must be logged in to reply to this topic.