1K Revision

This topic contains 4 replies, has 2 voices, and was last updated by  scottle 5 years, 8 months ago.

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  • #12754

    scottle
    Participant

    Hi,

    What is the 1K revision. I went to Github to download the latest firmware for my NCM109 board but I don’t know which one to use.

    #12762

    Gra Afch
    Keymaster

    You must select firmware for NMC109 board depending on the top board model (tubes board):
    1K revision only for boards with 1 kOhm resistors at anode circuit. Here a places for these resistors:
    https://photos.app.goo.gl/oURU2ETeMHkjJrrx8
    On this board resistors marked as 103 this mean 10 kOhms (not 1 kOhm).

    #12767

    scottle
    Participant

    Thanks for that. I have the 1kOhm resistors (102) how is this enogh resistance to limit the current to the IN-18 tubes?

    #12942

    scottle
    Participant

    Hi, I’m still wondering about this. With a 1kOhm resistor the current through the IN-18’s would be 0.18A which is a lot higher than the rated current of 0.008A (MAX) I think the software is switching the tubes on and off at around 333Hz – is this correct? Does this switching mean a higher current is ok? Could you please provide links to the theory behind this and the calculations for current.

    #13028

    scottle
    Participant

    Hi,

    Could you please answer my questions above.

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