56 input schematics? Problems with 32 input Megadrum

[Ruiner46]

Hi all,
It's been a long time since I've been on this forum. I built a 32 input Megadrum years ago using Synthex's v2.8 PCB. It has been working well for many years, and just recently the Atmega died. I had already bought two Atmega 644's from Dmitri right when he started using the encrypted firmware. I removed the old Atmega and installed the new one. My Megadrum still has some weird issues. I can't get new firmware to load, so I'm stuck on an old version from 2010. The firmware load fails out with CRC errors. I've noticed that several inputs seem to be very noisy, which all could be related to a PCB problem. I'm planning to buy a new ARM based kit sometime in the future, but in the meantime, I'm trying to get this one at least a little functional.

I've noticed that all of the inputs with noise seem to be on the additional inputs for a 56 input board. Is there a reason that Synthex's old design wouldn't work with 56 input firmware? Are there 56 input schematics around somewhere? I've only found 32 input versions. Any suggestions for a way to disable the extra inputs? I've turned all of the gains to zero and the thresholds up to 127 and I still get false triggers on those inputs. Other than the false triggers, the rest of the inputs seem to work ok and I was able to setup 4 pads, a kick and three cymbals and they trigger ok. I just need to get rid of the false triggering on the additional unused inputs.

[dmitri]

Hi all,
It's been a long time since I've been on this forum. I built a 32 input Megadrum years ago using Synthex's v2.8 PCB. It has been working well for many years, and just recently the Atmega died. I had already bought two Atmega 644's from Dmitri right when he started using the encrypted firmware. I removed the old Atmega and installed the new one. My Megadrum still has some weird issues. I can't get new firmware to load, so I'm stuck on an old version from 2010. The firmware load fails out with CRC errors. I've noticed that several inputs seem to be very noisy, which all could be related to a PCB problem. I'm planning to buy a new ARM based kit sometime in the future, but in the meantime, I'm trying to get this one at least a little functional.

I've noticed that all of the inputs with noise seem to be on the additional inputs for a 56 input board. Is there a reason that Synthex's old design wouldn't work with 56 input firmware?

Not that I know of.

Are there 56 input schematics around somewhere?

viewtopic.php?f=3&t=1623

I've only found 32 input versions. Any suggestions for a way to disable the extra inputs? I've turned all of the gains to zero and the thresholds up to 127 and I still get false triggers on those inputs. Other than the false triggers, the rest of the inputs seem to work ok and I was able to setup 4 pads, a kick and three cymbals and they trigger ok. I just need to get rid of the false triggering on the additional unused inputs.

Two ways.
1. If the non-functional inputs are only high numbered inputs then you can set MaxInputs lower.
2. Any input can be disabled by setting Note to 0.

[Ruiner46]

Thank you, setting the note numbers to zero worked for me. My firmware is so old, I don't think it has MaxInputs. It's version 20101020.

Now I just need to figure out why the new firmware won't update. When I choose the crystal frequency and press down, the screen flickers a few times and then it resets without loading firmware. I also can't use MCT for anything but a MIDI monitor. Nothing else works, can't view or set any settings. MIDI out over USB or the MIDI port works fine though.