Hi all, pleased to e-meet you.
tl;dr - can anything apart from busted faders make DM1000 faders behave weirdly? And what does "WARNING: SUB or MTB RX: check sum error" mean on a DM1000? How can I go about looking into it? Thanks!
Longer version: a few months ago, I stumbled across what seemed like a really good deal on a DM1000, seemingly in great condition. On picking it up I booted it, tested out a few sliders and switching views. It seemed a liiiittle bit clunky, but seemed to be working, battery check was good, so I figured it had just been in the guy's cupboard for a while and a good clean-up would fix it.
On trying it out properly it turned out that 5 of the sliders were really not working properly, clicking and clunking and doing some strange switcheroo patterns between track view changes. I successfully upgraded the firmware to 2.41-3 VCM, and tried running the calibration tests, but it seemed to just loop running the tests over and over, presumably (I thought) because some of the faders weren't working. Didn't get any further with it than that, as it wouldn't be much use with 5 busted faders, so I ordered some spare parts, got everything prepped, and then life got in the way for a while.
Today I finally got round to spending some time working on it. I've replaced the 5 sliders and the screen; refurbished screen looks great, and 4 of the sliders work better now, but the 5th one (track 12) doesn't work at all. What's more, the calibration still gets stuck in the same loop, running tests over and over, bottom to top, bottom to top. And I'm now noticing that I'm getting a WARNING message at boot: "SUB or MTB RX: check sum error". At first I thought this was some motherboard/other-board comms error, I guessed because I must have messed up some of the connections on re-assembling, but I've been through all the cables, re-seated everything and it's solid. I've checked all the solder too. And I don't think I was getting this message before, but I'm only half sure of that.
I'm also noticing that some of the buttons on the UI don't work, especially some of the menu buttons, in columns - on the DISPLAY ACCESS menu, column 1 works (so AUTOMIX, MIDI, PAIR/GROUP and PAN/SURROUND all work), but the buttons in other columns just don't do anything. Other buttons respond intermittently, including the tab selection buttons under the screen (left and right arrows and whatever's in the first tab all work but others mostly don't).
Again, I don't know if this was how it was before, and it's totally possible that I messed something up while disassembling for the fader replacement, but I've (at least) triple-checked and everything seems to be stable. Faders are also still doing kinda strange patterns when you switch track views.
So I'm wondering if there was just some other underlying error all along, maybe some more fundamental control issue, and maybe the faders were a red herring. Anyone know what the "SUB or MTB RX: check sum error" warning means? Sounds like some comms thing, but I can't find anything loose or flaky, and I can't find it even in the service manual.
Anyone got any clues or ideas of what I could/should try to do next?
Thanks a lot!
