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[nochtanseenspecht]

--casiotone mt-400v--
my little daughter found one in the garbage, and took it home for daddy

after taking the dirt out, mostly wet dust and birdshit, it started to work again and i realized what a great
present it is, especialy after calibrating the trimpots for the filter and resonance

this is an early eighties analog keyboard (same size as cz101) with 20 preset voices, a warm controlable chorus,
12 differend rhythms,  noise generator, bass and chord accompanyment, each with 4 variations and an
enveloppefilter wich, after trimming, easily goes into selfoscillation ! this filter has slidercontrol for attack,
decay, sustain, cutoff and resonance, as well as an lfo over cutoff (auto wah) if desired, and also has an
input for external control 
it is possible to route either voice, noise, drum, or accompanyment trough the filter.
also bass, drums and chord have a separate volume slider as well as a master volume slider

it is more like a synth since the filter is so powerfull. i see it as an early groovebox

i want to bent it in style, so i realy gonna take time to find the right knobs etc.. at least i will put :
- filter external in
- seperate outputs for drum, bass, chord and voice
- mute switches for hihat, kick and snare
- distortion
if i find it i will put :
- chorus external input
- rhythmic variations
- and the holy grail : kick decay control (if possible)
- trigger in for the sequencer (midi ?)

i think this keyboard is all analog, somebody knows ? it is filled with circuitboards, trimpots everywhere
i think it is the best of all small casio's ! (exept cz101 maybe)
has anyone been modding this sweetheart yet ? or other ideas ?
anyway, i advice everyone to find a mt400v

demotrack sooncome !

[Signal:Noise]

You've trained you young one well I see. That's quite some find.

[nochtanseenspecht]

hehe,  yeah, like me she's got a nose for good garbage ! quite often she brings home things from the street

meanwile i found a lot of interesting info at the good old Tablehooters' :

http://web.archive.org/web/20040831062937/users.informatik.haw-hamburg.de/~windle_c/TableHooters/Casio_CT-410V.html

sounds all very promising... it seems that the kick decay will be the easyest part 
even an arpegiator is hidden inside...
...lucky bastard 

[nochtanseenspecht]

okay, i put the 4 individual outs and the mute switches on the drums...all very nice and recommendable
but now i want also the arpegiator ! and the enveloppe select, and the manual bass and the keyhold aswell..
Tablehooters describes very clearly how to connect these features on the processor chip, the NEC d9306,
wich is a 80 pin square chip on the mainboard,  problem is, i don't know where to start counting 
there's no sign, no dot or something, that shows wich is pin 1
any idea someone ?

[catweazle]

here it is ...

there should be a little spot/mark/dot or one corner is flattened,
there is pin1 (like on all other ICs)

[nochtanseenspecht]

Thanks !

[nochtanseenspecht]

i uploaded some demotunes on wich you can hear the effects of the first bends that i have installed on my mt400v

http://www.esnips.com/web/modifiedcasiomt400vtunesandpics/

i think
http://www.esnips.com/doc/0d601694-2ccd-446d-9e6a-ddd42af1cfb2/met-muteknoppen-1
and
http://www.esnips.com/doc/24c4080b-d3aa-4a92-8658-cf834662a644/met-individueel-uit-1
are the best so far

if more mods are installed, i will put some more demo's

[audioresearch]

Hi all, First post from a long time lurker

Nice demos 

I've also have an mt400v I got off ebay ages ago for £20. I had loads of plans to mod/bend it but have't even opened it up yet, so it still has the standard lame resonance, I'm definatly going to have a fiddle with it this weekend after hearing your demos. very acid 

I also got a  mint mt65 I picked up really cheap with the idea to copy the arpeggiator and  alternate envolope sections and then sell on, other than those two things and the filter they are very similar.  I did open it to adjust the analog drums but did'nt poke around. If you want any photos of the circuitboard to help you figure out the arp let me know. BTW it's not a real arp, It just plays a selection of fast (16th?) blippy patterns. I can't remember if they change key with the chord accompanyment  or not but it's not terribly exciting. Might sound better thru the filter?  If you want a quick demo of the arp it's not much trouble, when I find the time. The env is definatly worth adding.

I can think of loads of things to mod, heres a few ideas-
The drums on the mt-40 ( Ive a 41) are similar and I've spent a few hours in the past with alligator clips and pots, there's lots you can do to the drum sounds, I think trigger in or a sequencer would be most useful though. (unfortunatly the mt40's jungle grooves mod dosent apply to the mt400 ) I heard you can make a drum sequencer by modding one of those led chaser things. Or if you want midi then highly liquid has good stuff.
The sound is created digitally, basicaly a binary number is converted into a waveform;  0 = silence 1 = square then it's muffled with caps, Theres a really good explanation at Warranty void's new site  http://weltenschule.de/TableHooters/index.html
not the waybackmachine archived link posted earlier.
If you really want to get hardcore, Robin Whittle (the aussie who does the devilfish mod for the tb303 etc) had newsletters on modding casios in the '80's and on his site are details and software for editing the voices on the mt65 which should work with the mt400v.  Not just an early groovebox but with early computer editing too
Cheers.

[nochtanseenspecht]

Hi Audioresearch,

that is good news ! and  thanks a lot for your info !
i definately will install the enveloppe select and the arpegiator (a short demo would be nice though )
drum triggers...that would be nice ! i think the sounds of the drums are okay, i found only the rhythms
not so interesting...but if one could trigger them...

maybe the arp. would be more exciting if it is routed to an individual out, so it can have it's own fx.
i found that each sound have differend timbres along it's signal path, depending on where you connect it's
individual out on the mainboard, wich is also interesting. only the snare is a bit more difficult as it is not
just one sound

i plan to do most mods that discovered by the Great Tablehooter, only i do them one by one, and after each mod
play and record for a while, so that if i fry the keyboard, at least i'll have some cd's to remember it   

[audioresearch]

Thanks, I'll record a quick arp demo somtime this weekend. If you like squarewave casios with filters theres a ht700 on  uk ebay currently at £15 to finish in 2h or a ht3000 (same but fullsized 61 key ) in a few days no bids at the same price. I've a 700 and it's quite fun, theres some info on modding the filter etc, same filters as korg poly? / 800? and I'd imagine the pcm drums are easy to bend etc, plus it has midi and basic sequencing, for drums it's similar to yamahas custom drummer.
 
Anyone who likes the demo's and wants to bend there own mt400v theres one on ebay finishing tommorow at £5 right now, I'm tempted to bid myself because there quite rare and usually go for much more.
Cheers.

[stoicboy]

I just got one of these myself, and information is fairly scarce. If anyone has any info they can offer, I'd be much appreciative. Mine's in near-mint condition.

[nochtanseenspecht]

there is loads of information on the Tablehooters site,
http://web.archive.org/web/20040831062937/users.informatik.haw-hamburg.de/~windle_c/TableHooters/Casio_CT-410V.html
the ct-410v has the same circuitry as the mt-400v.

best thing to start with imo, is to put a diode where the power comes in, and second trim the resonance.

i just installed the arpeggiator mod and the enveloppe mod, both very nice. next will be the sustain mod
many things possible with this machine, but not enough space to install all. you must make a selection

[dok]

I'm working on my MT-100, looking for mute switches for hihat, kick and snare, but without any success.
Could you please explain a bit how  you succeeded ?
thanks in advance

[nochtanseenspecht]

hmm, if i remember well, i searched and found the traces of the individual sounds... cut the lines on the
circuitboard, and bridge the cut with a switch... it wasn't difficult at all, you just have to find the individual sounds
on the circuitboard. mute switches make the drums far more interesting.
mt100 i don't know, but if you're lucky there might be trimpots for kick decay and snappiness

[dok]

Unfortunately I still can't  find these traces that's why I was asking for some infos.
According to your memories, are these separate sounds linked with the NEC D930G (80pins, the one that allows various functions such as reverb, envelope).
As far as I know the MT-400V and my MT-100 share (at least) this same chip.