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ELMO ST-1200D Sound Issue #2 - Robert

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  • ELMO ST-1200D Sound Issue #2 - Robert

    Rather than have two different technical issues compete in one thread (one from Adam, the other from Robert), I've created this one to separate the two.

  • #2
    I am new to the Forum and have been looking at sound issues with the Elmo ST 1200. I just purchased an Elmo ST 1200D and realized how to get the projector to work with the reels turning. I didn't realize you have to pause for a short period of time before going to the full reel turning projection. I am having problems getting the sound to come out. I played a mag strip film with sound and it was not coming through. I had the switch turned to Mag "M" and...nothing. I took the back off to look at two fuses I believe may be associated and they looked intact and good. I was surprised to see that the back cover with speaker was not even connected to the main projector through an electrical wire. totally independent as a stand alone speaker. Nothing in the instruction manual describes how to use this speaker other than connect to it. Is there a separate speaker in the Elmo, since this is independent from the projector? I have heard so many good things about the Elmo ST1200 so I was lucky to purchase one for $150. I had films that would flutter on my GAF 3000s projector and used in the Elmo...Just Fine. I love it. Just need to get the sound working. I can hear the volume go up and down with the volume knob (hearing a hum only). If anyone can give me some idea what to do, I would greatly appreciate it.


    • #3
      As you can hear a variable hum but no magnetic sound I suggest you flip the M-O switch backwards and forwards a number of times to clean its contacts. This may help.


      • #4
        Robert, the built in speaker on the ST1200 models connects to the amplifier via two metal connector tabs that make contact and connect it when the back cover is in place, hence no wires.

        But this is the only speaker on the projector, it is just a clever design to allow the back cover to be removed easily.

        Also, just a thought, but is your HD a twin track machine? If so, check switching tracks on the rear of the machine.

        The fact that you can hear hum increasing / decreasing is reassuring.

        Maurice's suggestion is a good one.


        • #5
          Maurice & Rob, Thank You for the input. It is great to be able to have assistance for a hobby that is probably a lost art for many. I have tried playing with the volume knob, (as well as the on/off) and the "Record" button. I did switch the M-O switch but not back and forward multiple times. I will try that. I very recently discovered the prongs you mentioned that make contact and used a pencil eraser to clean the prongs. The "D" projector is fairly clean. I hope this works. Thank You both for being there.


          • #6
            Maurice & Rob, Tried maneuvering the O-M switch back and forth with no success. I believe I have a good speaker, will continue to work the O-M switch to see if it eventually starts to bring back the sound. I have never cleaned a sound head, I believe using an alcohol wipe. I received this projector in the mail from the far southern part of the country to travel to the most farthest NW part of the country with little cushion packaging. Possibly something worked loose. I have read on some of the threads on the forum where the sound head may have shifted. If so, I would definitely need to see photos (or very detailed description) to know exactly what I should be looking for, to understand what corrections, if any needs to be made. Thanks again for your feedback.


            • #7
              One thing to look for is if the presser is bringing the film down onto the head. If it isn't closing down the stripe and the head will not be in close contact and you will not get sound.

              When you adjust the control knob, the chute the presser is on should be open in most knob positions to allow the film to autothread, and then when you go into forward projection mode, the chute should clamp fully down.

              On one of my machines, some debris interfered with the internal linkages and the chute stayed open.

              One trick I'm fond of is to bring a demagnetizer tip near to the head and listen for the hum to change. (Granted, not everyone has one!)

              -at least than I know everything is connected up and the signal is getting through the amplifier.


              • #8
                Indeed I have a Eumig in which (among other things now) the pressure pad assembly has completely fallen apart - no sound. As it only cost me £10 at a BFCC and it is one without a top sprocket I just use it occasionally for silent showings and keep for spare parts.


                • #9
                  Click image for larger version

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ID:	77029 If someone can tell me if the film is traveling over the sound head of my Elmo ST1200 D properly. I have tried using earphones to bypass the speaker but still hear the volume increase and decrease, straining to hear something. Steve, can you tell me if this looks right.



                  • #10
                    Hi Robert,

                    Within the limits of your pictures, it looks like the presser mechanism is doing what it should. Even if it was just getting close, you should hear popping and bits of sound track as the stripe slaps up and down on the head. I think your presser is at least trying and the problem is elsewhere.

                    Here's something to try: find an ordinary permanent magnet, like on your refrigerator door(-especially if you have kids!). Put the machine in projection mode with the volume up and swipe the magnet near (-but not on) the sound head.

                    Do you hear some kind of a "pop" as the magnet passes the head?


                    • #11

                      Yes I do. as I move it close it starts a warbling sound.


                      • #12
                        Can I use any demagnetizer on my projector, like the handhelds used for tape decks? Any concerns or things I need to avoid other than making sure the power is off to the projector? I assume, if I do get one, it it merely just passing over the sound head a few times?


                        • #13
                          Hi Robert,

                          Yes you can use a demagnetizer, and it's good if you can get your hands on one. It has a special use in cases like this.

                          Plug in the machine and turn on the sound. Power up the demagnetizer and slowly approach the head. As you get nearer the low hum that is natural to the machine should get louder as the demagnetizer approaches the sound head.

                          It's like the test above, but it is a longer operating time.

                          Since the demagnetizer provides an oscillating magnetic field, it simulates the signal from a sound stripe. I'm guessing it's a much stronger field than soundtrack, so you don't want to start too close with the Amp powered up.

                          Now, under more normal circumstances, you would have the machine powered down and slowly approach the head then slowly withdraw. I do this on my own machines here and there. I can't say it's made a colossal difference, but it's basically good hygiene!


                          • #14
                            I can't seem to understand why I get no sound. Sometimes when the end of the film passes the sound head, I hear a loud pop. A closer inspection shows a roller actually pushes the film directly over the sound head. If a demagnetizer doesn't work. I will just get another projector or pack for repair possibly in Seattle or NY.


                            • #15
                              I'll be pretty honest this one has me stumped too!

                              I've been through this kind of stuff many times, both at home and at work.

                              What's sad is after you DO figure it out, it seems so obvious!

                              (-especially to the people standing on the sidelines!)