Modypoly hung notes and strange behavior after hires

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  • This topic has 15 replies, 1 voice, and was last updated 8 months ago by Anonymous.
Viewing 15 posts - 1 through 15 (of 16 total)
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  • #8566
    Anonymous

    Hi Group

    After installing Hires in my Polysix (modypoly was already installed) everything was working well. After a month or so the polysix started behaving strangely. I will get random held notes and arp starting without being engaged. Also a chord will play on D# without chord being selected. I have updated to the latest firmware but no change. Firmware reset does nothing. If I toggle the hold or latch switch it will go away but soon returns. The only thing that seems to make it stop is to disconnect the keybed.

    Any help would be greatly appreciated so I can start using this again.

    Thanks!

    #8567
    tubbutec
    Keymaster

    Hi,
    tha fact that it worked at first and then later failed, points to an intermediate issue, maybe a bad contact. Can you put some pressure on the ModyPoly and check for shorts and solderbridges where you installed the HiRes board?
    Also post some pictures, that might help

    #8568
    Anonymous

    Hi!

    Thanks for the response. Sorry for the delay I was not getting notified and have now changed to receive them. I checked all the solder points and there are no shorts or bridges and all contacts are good. Here are some pictures.

    Thanks!

    #8569
    Anonymous

    I also reflowed all the solder connections for the hi res and modypoly as well as the keyboard connector but still have the same problems. Thanks.

    #8570
    tubbutec
    Keymaster

    What happens if you unplug the potentiometer connection? Does this change the behavior?

    #8571
    Anonymous

    Hi. No unplugging either connector from the hires does not stop the issues. Only unplugging the Keybed. Thanks

    #8572
    Anonymous

    Hi

    Any other suggestions?

    Thanks

    #8573
    tubbutec
    Keymaster

    The best thing you could do is to put back in the original CPU. Just to see if the issue is caused by ModyPoly or by something else in the Polysix.

    In case you do not have that anymore:

    Which D# plays the chord? That might help

    The only other thing you could try at this point is to try and remove the HiRes board.
    this way we could at least check if the issue is caused by it, or by the rest of the ModyPoly circuit.

    #8574
    Anonymous

    Hi

    Thanks for the reply. I have been looking for the old CPU but have not located it yet. I have the one from the Juno-60 but I imagine that is programmed differently?

    The D# playing the chord is the one just above middle C (center of the keyboard).

    I will next remove the Hires board and see if that solves anything.

    Thanks!

    #8575
    Anonymous

    Hi. I removed the Hi Res board but the problem still persists.

    Thanks

    #8576
    tubbutec
    Keymaster

    Did you try the original CPU? Maybe the problem is not ModyPoly related at all …

    #8577
    Anonymous

    Hi

    No I have not tried the original CPU as mentioned two posts up. I will see if I can buy a new NEC CPU and test it without the modypoly.

    Thanks

    #8578
    Anonymous

    Hi

    I ordered a new CPU chip so I will be able to test later next week. I will post the results. Thanks!

    #8579
    Anonymous

    Hi

    So I bought a CPU chip off of Reverb and it arrived today. I put it in and the Polysix works well at first but after being on for awhile the sustain notes begin. When I put the Modypoly back in the problems outlined earlier resume as well. It seems the issue is with something else in the synth. Perhaps with the VCA or envelopes.

    Thanks

    #8580
    tubbutec
    Keymaster

    thanks for letting us know. Good luck with the repair

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