Cheetah MD-16

[djsynchro]

I've got a Cheetah MD-16 which I want to bend (of course...heh). 

Already located the 2 EPROMs that hold the sample data... ready to go... but I can't find the blinkin PSU!
It connects to the Cheetah with a DIN plug (same as a MIDI connector) and no markings whatsoever. Does anyone know how many volts it is, is it DC and if so how it's wired?

Cheers!

[Circuitbenders]

The power supply on my MD16RP says 9V 1A DC on it, god knows how its wired though.

There are only two wires despite the DIN plug so it shouldn't be that hard to work out.

[djsynchro]

Hey thanks very much man!

I think I'll be able to work out the polarity, yes. Was rummaging around in boxes trying to find the PSU no joy, but I did find a sounds cartridge "Kicks Snares Toms & Hi Hats" I remember I wasn't so charmed by all the sounds when I bought it, way to Rock & 80's sounding.... EXACTLY what i'm looking for now   plus some distortion & Glitch of course.

Did you bend your Cheetah?

[djsynchro]

Got an adapter going... hurray. Do you know how to force the "cold start"? (hard reset)
It asks "Cold Start?" everytime now, maybe it needs to charge the backup battery first?
Was thinking of leaving iot plugged in for a while then resetting it. It made sounds for a minute, now it's acting weird.

[Circuitbenders]

According to the mammoth tome that is my MD16RP manual, when it says COLD START? :

'There are two ways to progress. You can either select a cold start where the MD16 clears all the memory and sets up default settings, or you can attempt a SAFE satrt where the MD16 will attempt to correct the situation. When prompted, to select a COLD start press SHIFT START/STOP only, to select a SAFE start press SHIFT PATT only'

So there you have it, as with everything else on this machine even a factory reset is suspiciously complex. I've never got round to bending my MD16RP as its a rackmount and i'd need to get hold of another rack case to mount the extra controls. To be honest its brain meltingly complex enough already 

i will gladly give my left leg to anybody who can supply me with the 'electronic' cartridge for the MD16

[djsynchro]

Thanks for the info!!!
Question though: Is there a button I can hold down when I start it up to FORCE it to go into the reset routine? I already poked around at the sound chips, not much great glitch yet but a lot of crashing (including Japanese characters)
And then it got stuck and didn't ask "Cold?" If I remember well there is a button to press when powering up that makes it ask the question?

[Circuitbenders]

Hold the SHIFT key down 'as you connect the power', according to the manual.

[djsynchro]

!!!!
You are a star!
Will let you know how it went...

[djsynchro]

It's glitching alright... The other ROM chip is the one to poke around with.  Apart from a couple of pins that lead to silence and/or crash most pins are cool bends. So it's going to be a patchbay, 16 connections (out of 25 useful ones I found) and two helper switches to start with.

It's 15 years after it came out and I might finally like it  Actually, it already does fairly extreme grungy pitchshiftng, will be very interesting in combination with the bends.

[djsynchro]

Hey paul, I'd like your expert opinion!

So  I found about 25 bends in the Cheetah, picked the 16 most interesting ones.
Also tried to pick the more stable ones, cuz when the Cheetah crashes it crashes quite badly garbled display & stuff so then you need to cold start it.

Put in a patchbay, connected the 16 bends & a reset switch.

Closed it up, worked normal. Quickly tested all the patchbay connections. All were doing something.
So, I set it up for a serious glitch session with MIDI going into it. But as it turns out it crashes pretty much with every connection...

Had a quick look inside again, all the wiring seems OK (but will double check tomorrow)
What do you think it could be? It was fine when I was manually shorting pins with a piece of wire.

Cheers! 

[Circuitbenders]

Is it a metal case? If so there may be some wierd grounding problems with the jack sockets grounding to the case. Otherwise the major thing you want to be checking for is if the jack sockets are touching any components inside when you close the case up. I've had nightmares trying to work out what the hell was going on with a 505 whenever i closed the case until i realised two of the jack sockets were shorting to the top of a big capacitor.

Does it only crash using MIDI or does it do it with the internal sequencer as well. I've never come accross a drum machine where the MIDI is affected by bending the sound ROM but there a first time for everything.

[djsynchro]

Bingo! You is a genius...

Not a metal case but there's a cooling element on a power regulator that was probaly touching some of the added wiring. Need to take it apart and do it again, insulate the wires and stuff.

Sound verdict so far: It's OK but not ultra amazing. I think I really want to find myself a TR or an RX

[djsynchro]

Latest update: Something is wrong, got insulation tape over everything that might short-circuit, but it's palying up again. Got a bunch of gigs coming up so for now that Cheetah is SHELVED. Bummer I really wanted a drum mangler oh well.

It's Queensday tomorrow in Amsterdam, like a giant carboot sale. Every person & their dog is sitting in the street selling their old crap. Hope I'll find some bendables

[djsynchro]

So I got it working kinda. If you have a Cheetah and you don't like it (like me) you might as well bend it. It will stil work as normal without patch cables. It's quite crashy so you'll have to do a lot of "cold" starting.

If you lost the PSU like I did, don't connect a 300mA PSU like I did, cuz it's oveheat and break! 
So I'm off to get a proper 1A wal lwart now.

Bending details: When you open it there are two large chips next to where the ROMpack connector is. The chip closest to the connector has the most bends on it, I only used one on the other chip.

[Circuitbenders]

So does anything happen if you just short the pins of the ROM port?

Could be an easy way to whip up an external patch box.