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Need Hammond M 102 help

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  • Need Hammond M 102 help

    Hi, I've been out of commission for a while. I'm disabled meaning my physical mobility has been severely limited for bending / twisting / lifting for the past 10 years. During this time I acquired a non working Hammond M 102 that someone wanted out of their garage. With the help of some good people here a few years back, we got her running . Over a year ago, I had to move, injured myself worse and haven't been able to play since moving. The organ got a broken key during the move and I haven't been able to fix it due to my injury, until just today. I just replaced the broken key, oiled her yesterday, blew out the dust and now there's hardly any volume coming out of the organ even with ALL the tone bars pulled out...drawbar tabs depressed. Very very weak. The bass pedals aren't producing any sound at all. The tab for "Volume Soft" doesn't help. I can't hear the Vibrato at all. On the positive side, the motor sounds good and it's spinning just found. I have a non amplified Leslie 125 ( no horn) , but I haven't hooked it up yet. The organ should be able to produce reasonable volume on it's own and thought it would be best to get it working right before adding the Leslie.

    With the help of the meds I have to take, I've forgotten a lot of the basics of the trouble shooting procedures.........any suggestions on where to start ? Any help is much appreciated...I've missed playing a lot.
    Now: 1961 Hammond Extravoice F 100 , 1964 Hammond M 102, 1964 Leslie 125, Roland U20,
    1959 Jensen BF-100 Cabinet w/ 12" 2-way coaxial speaker H223F (cork sniffer worthy)

  • #2
    If you can hear a weak sound from the organ, this suggests to me, that one of the amplification stages is not working, but the signal is bypassing that stage via the feedback loop.
    So I would start by pulling out the tubes and cleaning pins and sockets with Deoxit or something similar and look for bad solder joints.
    Other people way have better suggestions

    Comment


    • Jim Dep
      Jim Dep commented
      Editing a comment
      Thank you, that's a start. I pulled the 3 large tubes just before the move, kept them in a box for over a year and put them back in yesterday. All the tubes are glowing, no popping sounds, all the tubes seem tight enough, but I haven't used contact cleaner. I'll pull them and spray all the sockets 1st, and take a closer look at the solder joints. Good suggestion, thanks. btw....the upper keys on both manuals are even weaker than the lower keys....can hardly hear them at all, even with all the tone bars pulled out. Bass pedals aren't making a peep........very distressing. Thanks....I'll report back in a while.

  • #3
    Good to see you back on here Jim! IIRC there is a molex connection from the tabs that might require cleaning or jiggling but it's a long time since I was in an M100 as well.
    Hammond C3, M102, XB3, XB5
    Lowrey Heritage DSO-1, H25-3, Yamaha E70
    Farfisa Compact Duo Mk2, Vox Continental 300, Korg BX3 Mk1, Leslie 122, 145
    www.drawbardave.co.uk

    Comment


    • Jim Dep
      Jim Dep commented
      Editing a comment
      Thanks Dave...yeah it's been awhile. Anxious to get back and start playing again ! I'll be checking out the tabs and tubes more thoroughly tonight.

  • #4
    Update: The problems remains, however the volume came up for about 20 seconds on everything, even the bass pedals. I went to test each bass pedal and the volume dropped back to a whisper and bass pedals cut out completely again. Before the volume came up, I was turning the Pedal Volume knob on the bottom of the amplifier. I'd done this before and nothing happend. This time the low frequency started to feed back. I turned the knob to stop the feed back. Both reverb tabs were down and it sounded like a reverb low frequency feedback. The most volume I can get out of the organ is with both reverb tabs depressed (ON)...but normally only play with one when the organ was working right. Anyway, that was it. I can't get the organ to repeat what caused the volume to come up.

    All the tubes were pulled and I used a contact cleaner for the sockets...no change. I checked carefully for bad solder joints, loose wires...nothing. I do have the top off with the tabs and draw bar wires exposed. Everything looks ok.
    Where do you suggest from here? Thanks
    Now: 1961 Hammond Extravoice F 100 , 1964 Hammond M 102, 1964 Leslie 125, Roland U20,
    1959 Jensen BF-100 Cabinet w/ 12" 2-way coaxial speaker H223F (cork sniffer worthy)

    Comment


    • #5
      I just lightly tapped on a "new (couple year old with not many hours) " 6V6 tube I'd received from ToneWheel General Hospital and it exploded with broken glass flying.....is that a red flag ?
      Now: 1961 Hammond Extravoice F 100 , 1964 Hammond M 102, 1964 Leslie 125, Roland U20,
      1959 Jensen BF-100 Cabinet w/ 12" 2-way coaxial speaker H223F (cork sniffer worthy)

      Comment


      • #6
        The exploding tube is just bad luck, older tubes manufactured from the 70'back are far less likely to do this!
        If your sure you have checked all plug in connectors and solder joints then the next step is to check for correct voltages thru out the amp,you'll need to download the M series service manual from archive .org and you need to have a suitable multimeter and electronic fault finding knowledge.
        I suggest you visit the bentonelectronics.com website where he outlines the basics of faultfinding a B3 amp, very similar to the M100 amp.

        I use a Fluke117 multimeter with parrots beak clip connectors, that way, the display does not jump around,voltages are measured with the amp on it's side, tubes plugged in, that way you get real operating condition measurements.

        Comment


        • Jim Dep
          Jim Dep commented
          Editing a comment
          Thanks Geoff.. Thanks for the links, and all the good info ! You don't think it could be just the bad power tube ? I'll start reading up to put a plan together.

        • geoffbrown
          geoffbrown commented
          Editing a comment
          Yes it could be a bad 6V6 but you would need to test it to confirm that, either in another organ or a tube tester,fault finding is a process of logical elimination

      • #7
        To make things worse, I did a really stupid thing. I had what I thought was a spare 6V6 to replace the one that exploded. I plugged it in and turned on the organ. No volume at all, as I went to the front to pull all the tone bars out again....and then I smell smoke, go around to the back and see smoke coming up from the transformer. I killed the power and also saw smoke coming up from the bottom of the tube I'd just plugged in. I let it cool down, pulled it out, looked close and saw it was NOT a 6V6 ! I can't believe I did that. I can find another 6V6 on line ....but how much damage just happened in a few seconds ! I guess one day I'll find out.
        Now: 1961 Hammond Extravoice F 100 , 1964 Hammond M 102, 1964 Leslie 125, Roland U20,
        1959 Jensen BF-100 Cabinet w/ 12" 2-way coaxial speaker H223F (cork sniffer worthy)

        Comment

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