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Thread: Saving my H112

  1. #21
    ppp Pianississmo Marino's Avatar
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    Hi Bob, thanks for responding.


    I think I've seen all your videos. They helped me tremendously in dismantling. Especially the video where you show how to detach the tab panel, I never would have found that


    No matching transformers? Well, then it is already one thing less to worry about .


    I already cleaned the connectors and tube pins with deoxit. I will certainly try your other tips.


    The service bulletins are great information, which I have not found yet, thanks.


    The small pots, do you mean the blue ones?
    I understand that it is not easy to determine something from a distance, but I am already happy with the tips that can help me.


    The nasal sound came after I disassembled the H and the pop sound came later. Is it a coincidence, I do not know. Perhaps one problem creates the other?
    The speakers sound really good when I play the upper manual.


    This weekend I will work on your tips, thanks again

    Regards, Marino
    Last edited by Marino; 09-13-2018 at 11:04 PM.

  2. #22
    mf Mezzo-Forte Jaim's Avatar
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    The H doesn't have a matching transformer like the multi tap primary the 3 series has. However the block diagram refers to a matching transformer (MT) - I attached a snippet of the schematic which shows a transformer with a resistor ladder type input.

    My theory is the nasal sound is caused by a odd harmonic leaking in. Since the MT is the mix point for the harmonics - that is the logical place to start looking. Where is it? Don't know - however if you look at the right side (column) of the preset panel(s) in the other series of organs it was used to connect the preset panel and drawbar buss bars to the MT. So if you follow the wires from that preset panel column, one should go to the Draw Bar buss bars and the other to the MT.
    Xfmr.JPG
    Jim

  3. #23
    ppp Pianississmo Marino's Avatar
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    Thanks Jim, the snippet visually gives a better idea where to look.
    I know you said the resistors are 5 ohms but I read .5 ohm? I wonder if it isn't 0.5 ohm then, or does the dot have a different meaning?

  4. #24
    mf Mezzo-Forte Jaim's Avatar
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    0.5 ohms - more than likely it's resistance wire.

    Jim

  5. #25
    ppp Pianississmo Marino's Avatar
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    Sorry, I didn't explain it correctly. I mean the .5 ohm on your snippet, is this a half ohm (0,5) or 5?

    Xfmr.jpg

  6. #26
    mf Mezzo-Forte Jaim's Avatar
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    .5 - see my last reply

    Jim

  7. #27
    ppp Pianississmo Marino's Avatar
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    right , sorry

  8. #28
    ppp Pianississmo Marino's Avatar
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    Less time than I had wanted this weekend, car problems


    I have injected the sockets and pots with deoxit and the crackling and popping sound is as good as gone but the hum has increased. The connectors were already treated.
    I accidentally discovered when you come close to the pre-amp with a screwdriver, the hum increases.
    So I assume that the pre-amp is the biggest cause for the hum?
    Some tubes on the amplifier also crack a bit if you wiggle them. It's those that give a reverb-like sound when you tap it

    As the diagram indicates, the wires from the preset panel go directly to the drawbars.
    On the picture you see the connection points, can I assume that those blue blocks are the .5 ohm resistors? Can you unsolder this if necessary, they are very small?

    Marino


  9. #29
    mf Mezzo-Forte Jaim's Avatar
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    Could be - the object of this exercise is to make sure no shorts or dendrites between the terminals. Flush with de-oxite.

    The H series will hum without the preamp covers installed.

    Jim

  10. #30
    ppp Pianississmo Marino's Avatar
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    I have removed the tab panel again and found 2 broken contacts, the wires are very short. Can I extend the wires with wires of the same thickness or does this affect the resistance?
    I hope this will solve the problem.

    Marino
    Last edited by Marino; 09-17-2018 at 08:16 PM.

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