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Topics - hangnef

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MV-General Production / Volume levels after applying MFX
« on: October 19, 2019, 08:23:44 am »
I must be doing something wrong.  Every time I apply an MFX to a track, there is a massive volume drop, and I can't see to find a blend or gain knob anywhere to offset it.  There isn't exactly a lot of headroom as well to boost via the mixer.

The effects are great on my guitar, but the volume drop kills it for me.

I'm sure mv-nation will set me straight!  :)

2
MV-General Production / Possible enhancements/fixes for MV firmware
« on: July 06, 2019, 02:07:53 pm »
Hey MV-Nation!

I'm a fairly new MV owner and have made a few posts hinting about making some
changes to the MV software.  I've been working on this for a few months now
and thought I would share my ideas and progress so far.  I'll try not to get
too technical.   :)

I think the MV is an amazing platform (still!) and already does so much, but I
wanted to see if things could be improved, for instance loading times, or maybe
allowing a 2nd MFX.

So far I've been able to reverse engineer the boot program which has taken
about 2 months or so.  The processor is an SuperH-3 7706 and I've taught
myself the instruction set and what I needed to know to understand code that runs on it.
I got to the point where I determined the main program was embedded in the
.PRG as a compressed image as well as its exact location, so the next step was to
figure out how to unpack it.  Here's some pics of the annotated disassembly.

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Unfortunately, the compression type was an undocumented variant of the
LZSS compression algorithm, called LZ98.  Thankfully, the admin over at
encode.ru was able to take my disassembly and notes and generate a program to unpack it
and it does work.  I believe he is currently working on a packer, which I will need
to put back the binary with any changes I make.  Without that it will be much
more difficult to continue.  I would have to resort to using a different
compression algorithm to ensure the entire image can fit on flash.  This would
take some time.

[As a side note, the MC-909, FP-30, and other systems also use this
compression, so it's possible it will allow other similar projects to start.
The MC-909 also uses the same processor as the MV, so it's possible code could be
pulled out of there and put into the MV.]

I'm currently now going through the 7+ megabytes of code and it is quite slow
going as I have to mark regions as code and data by eye.  I am doing about
10k of code/hr so it will be some time before I have it all done.  Once that
process is done, I can start to see how much work is involved in making changes.
There should be enough room on flash to allow for a good amount of changes.

I also want to note that I own an MV-8800, but there is nothing stopping me
from making changes to the MV-8000 firmware as well, everything I've done so
far applies.  The only hurdles are fully disassembling the main MV-8000
program, which as I mentioned will take a LONG time, and getting a MV-8000 for
testing.  So if anyone has a beat up one they'd like to donate (I would return it when
done) or sell, please PM me.

Next steps for me are to find a beat up MV-8800 I can use for testing as I
will need to make HW modifications to it, like soldering in an H-UDI header so
I can program flash in the event I brick it and it allows for low level
debugging.  And I need to do a lot more reversing of the main program.  Also, the compression
program will be necessary before I can run anything new.  If and when I get to
the point of having actual changes MV users can install, I'll need to find
some web hosting for a forum, etc.

Some interesting findings so far in the unpacked firmware

- The code name of the project, or the GUI library was called "Miami"
- The string "cher" appears a few times and seems to be actually used   :P
- The code is written in C++, which makes things a LOT more difficult

I have no idea how far I will get with this, but I feel like I've come very
far already and have no desire to stop.  I'm so excited about this project!

I am open to hearing ideas about what you'd like to see added,
and also about any bugs you've encountered running the latest firmware.
Oh, and any changes I make will be free, I'm not going to charge or anything
like that.

I'm open to help as well, but due to this being proprietary code from Roland,
I don't think putting it up on github etc would be a good idea, so I'm open to
ideas on collaboration.  I had tried contacting Roland and their lawyers about
licensing the source code, but never heard back, so this was my next option.

If you got this far, thanks for reading!  And if anyone is interested in the
code or Ghidra project for disassembling, PM me and I can share.   I'll
post updates to this thread as I hit new milestones.

~hangnef

3
MV-Modifications / LCD on/off switch and silicone 'corks'
« on: July 05, 2019, 06:59:07 am »
I've just about finished updating my MV-8800.  It has one issue left which I'm hoping to have resolved soon (issues w/ Wave RAM, new stick coming).

I did a bunch of the usual modifications other folks have been doing including

- silent fan, Noctua... very nice
- SSD
- new LCD, easily purchased on eBay
- DVD combo drive (had to file part of the harness down to get the holes to line up)
- Replaced some of the loose pots
- Put in a set of blue pads from mpcstuff

I made 2 other modifications

One was an on/off switch for the LCD, so I can turn it off if I'm focused on the VGA screen.

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I also wanted a little more sensitivity, and I did the same trick I did on my Korg padKontrol.  I purchased a sheet of silicon rubber and cut into small squares and placed them under the pads.  I had tried making nice circles with a punch, but it just didn't work out well.

This is the sheet I used

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I'm going to make a separate post about the potential software fixes/updates that I may be doing for the MV series!

4
MV-Support / Done HW upgrades, stuck w/ installing factory content
« on: June 28, 2019, 01:27:37 pm »
I've just finished a slew of hardware upgrades to my MV-8800 (I'll post about that later), but I'm trying to install the factory cd content (demo projects, etc).  I've copied the demo prj into my projects folder, but they do not show up.

How do you go about importing a project?

Also, once I copied those files in there, it wouldn't let me delete them.  Is this where the "disable HD protection" comes into play?

thanks for any info,
~hangnef

5
MV-Modifications / Looking for nice send of end panels
« on: May 13, 2019, 06:13:32 am »
I purchase an MV-8800 and it seems to have been dropped and my end panels are all cracked now.

6
I'm in the process of getting a HW debugging environment going and reverse engineering the firmware for the MV-8800 and was wondering if a 1.00 MV8800.PRG exists?  It would help to compare against the 1.01 version when disassembling, etc.

I had reached out to Roland about licensing their source code or open sourcing it and was told "no".  I expected that, but thought I'd try anyway.

Any help greatly appreciated!

7
MV-Support / MV-8800 replacement screen
« on: May 04, 2019, 10:09:03 am »
I'm thinking of purchasing an MV-8800 but it has a very dim screen.  I know I can attach a VGA monitor, but I'd like to be able to also use the screen.  Does anyone sell replacements?

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