UNBENDABLE MACHINES list here.

[Circuitbenders]

I'm sure we'd all appreciate a list of machines that people have found to be unbendable, or if they are bendable are fairly useless. Make your nominations in this thread and add a little bit of detail if you wish although i wouldn't trust this list 100%. Just because someone hasn't managed to bend something doesn't mean its not possible. I'll edit this thread down to a couple of posts every now and then if this topic works out.

UNBENDABLE MACHINES:

Yamaha VSS-100: The sampling side can't be bent with any real success unless you just want a shitload of noise. Never tried the synth side. (circuitbenders)
Korg DDM220 / DDM110: Very difficult without much reward. (circuitbenders)
Speak&Music: Never found anything worthwhile on the UK version although the US and french versions may be different. (circuitbenders)
Casiotone mt-55: isn't particularly great either. There's bits there, but nothing outstanding. (Signal;Noise)
Yamaha PSS16: one chip wonder. (catweazle)
Bontempi Electronic Mini Keyboard B20(catweazle)
Yamaha PSS-12:  A few bends which alter the voices somewhat but nothing spectacular.  I have heard better reports for PSS-6 although I believe that is just a mono version of the PSS-12. (iqoruvuc)
Super Speak&Spell 1991  and  Super Speak&Math 1991:  both are nearly unbendable. (catweazle)
Yamaha RX-11 / RX-15: apart from a couple of weak distortions theres just a whole lot of connnections that lock up, reset and crash the machine. Major pain in the ass. (circuitbenders)
Yamaha PSS-30: One of the most unbendable chips ever (someone on this forum)
yamaha pss-50/pss-9 - these models are exactly the same with slightly different markings and model numbers. they solidly withstand any attempts to bend. gits... yamaha, what were you thinking? (andy wheels)
bontempi '666' range - evil italian unbendableness and easy to fry too. ugh. (andy wheels)
Cheetah MD8 - The most Volatile Non-Volatile memory you'll ever encounter. You have to load the sounds in from tape which never works and its so prone to crashing it even has a factory installed hard reset button!  (circuitbenders)
Yamaha PSS-50 - Only one chip so no seperate fm chip to cut datalines from!  Nothing interesting.  Real dissappointment!(iqoruvuc)
Yamaha PSS-80 - totally dissapointed with what I got from it. Probably the worst bend I have done so far!(creature)
Pre-school Musini - That wasn't much fun.  The normal version has a lot more potential appearantly, but I didn't know any difference when I bought this one.(iqoruvuc)
Bontempi 4400 - not interesting, doesn't smell nice inside either(nochtanseenspecht)
Finger Beats Finger Mixer  - This one is constructed to well, i had no luck with bending this what so ever. (davinyljunky)
Mekie 373D37 Key Kids Keyboard  - This is cheap china manufacturing at it's worst. Don't even waste your time on this one, it's cheap and nasty. (davinyljunky)
Machines Badged as Leapfrog - Probably doesn't apply to all of them but i've had a few machines made by Leapfrog and mysteriously none of them were bendable (circuitbenders)
TI MAths Marvel - i cant find any bends what so ever (matt the modulator) Same here (circuitbenders)
Fisher Price "Tune In TV" , Sesame Street version - It's got some kind of automatic reset that I can't bypass and pretty much ignores any bending attempts (egr)

[AttDestroyers]

"Yamaha PSS-30: One of the most unbendable chips ever (someone on this forum)"

Well I'm just here to say that I'm the proud owner of 3 of these baby's and I will be doing some serious in depth bending on this series when I get home from school next week. My goal is to seriously ruin this keyboards evening. So I'll probably post what I'm able to find/not find sometime in the next 3 weeks or so.

[bendboy]

The PSS-480 is a real pain in the ass....it has tons of chips and data lines, but ANY messing with them does a silent crash. The beats can be messed with, and the clock speed changed, but really, that seems to be it!!

PSS-6 keyboards can be bent to some effect (once crashed they can make some cool sounds) but there is not too much else there.

[englar]

I would add the italian DOTTO CONTA-PARLA it have made me crazy...nothing interesting....

only one chip and few components.It is not like the other TI toys.It doesn't have the pitch control.its pitch is controlled by a hateful blue crystal.
just a glitch and a a connection(it doesn't always work) that makes it to say random numbers.

[kingsteven]

"Yamaha PSS-80 - totally dissapointed with what I got from it. Probably the worst bend I have done so far!(creature)"

Yes, but still one of my favourite keyboards! :-D

[catweazle]

How about a extra Html page outside the forum with the "unbendable machine list" ?
I think this will be very usefull to see whats worse a buy.
(print out the list for the next flee market / hunt for bendables - trip)

[Circuitbenders]

I'd completely forgotten about this, i'll whip up an html page asap

[davinyljunky]

Finger Beats Finger Mixer - This one is constructed to well, i had no luck with bending this what so ever.
Casio SA-40 - Looks like so much potential and yes ok i have seen that this one has been bent before, but ultimately it's got nothing really going for it, very limited bends.
Mekie 373D37 Key Kids Keyboard (bad bad bad manufacturing) - This is cheap china manufacturing at it's worst. Don't even waste your time on this one, it's cheap and nasty.
Texas Instruments Touch & Discover - Unique it is (well at least 4 us Aussies) and not so much unbendable, it's just not worth bending as the sounds are not what you call usefull and it is difficult just to set up for testing the circuits.  I'm going to keep at it, but think i am wasting more time than what it is worth.

[Circuitbenders]

I got loads of good loops and glitches out of the Touch & Discover i bent a few years back. I don't think it is unique to australia, in that i have 3 more in my cupboard. Its a shame i lost the notes for it or i might try opening one up again.

If i recall correctly the SA40 does so great voltage drop crashes and theres a whole extra bank of sound effects in there somewhere.

[computer at sea]

I have heard better reports for PSS-6 although I believe that is just a mono version of the PSS-12

There certainly isn't a great wealth of bends to be found in the PSS-6, but there are some nice sounds that come from the few present.  As I recall, the harmonica sound does some great looping things.  The voltage drop crash works, to a degree, and produces a harsh blast rather than the aleotoric sort of blips that can be coaxed out of an SA-1.

Just shy of a one trick pony, the PSS-6 would be a great thrift shop/car boot sale find but not a reasonable eBay prospect.

[davinyljunky]

I got loads of good loops and glitches out of the Touch & Discover i bent a few years back. I don't think it is unique to australia, in that i have 3 more in my cupboard. Its a shame i lost the notes for it or i might try opening one up again.

If i recall correctly the SA40 does so great voltage drop crashes and theres a whole extra bank of sound effects in there somewhere.

I've got to be honest i have never seen a Touch & Discover before i got one to have a muck around with.... I'd be interested in any info you had on them, i just got sick of hearing "Hello Gangm Mickey Mouse Here, it's time to......." haha.  Like said the SA-40 is bendable, but it's not a wow factor machine.

[Circuitbenders]

i just got sick of hearing "Hello Gangm Mickey Mouse Here, it's time to......." haha. 

Oh great, i'd managed to successfully block that nightmare from my mind but now its back with a vengence. The way he says 'grrrrrrrreeeen' and 'bllllluuuue' is also infuriating

[S-CAT]

 
There is a good example of a circuit bent Korg DDM on you tube, no points for guessing who did it. It is a very awkward unit to work with and I found a crazy method to get the results. Basically I poked around until each percussion sound dissapeared and the with some more fumbling managed to get each sound back by jumping wires to each of the chips and resistors, I then noticed that the sound was only coming from one channel and decided to bridge the stero signal into mono on the board, the next strange thing that happened is that the hi-hat level started to generate bass tones when it was turned up fully. And when a 1/4" jack was placed into the headphone socket the machine reacted differently again. I've got another one here that I am working on but it's a slow process.

[Gordonjcp]

There is a good example of a circuit bent Korg DDM on you tube, no points for guessing who did it. It is a very awkward unit to work with and I found a crazy method to get the results.

Funny, the Korg DDM110 was the first drum machine I ever circuit bent.  They're almost trivially simple inside, with quite a few cool bends.  I sold mine after restoring it to its "normal" condition a few years ago.  Be careful, because there are relatively high voltages around the analogue section that will zap the logic chips - the "poke and hope" method is not your friend.

Basically I poked around until each percussion sound dissapeared and the with some more fumbling managed to get each sound back by jumping wires to each of the chips and resistors, I then noticed that the sound was only coming from one channel and decided to bridge the stero signal into mono on the board, the next strange thing that happened is that the hi-hat level started to generate bass tones when it was turned up fully. And when a 1/4" jack was placed into the headphone socket the machine reacted differently again. I've got another one here that I am working on but it's a slow process.

You really can't just poke randomly at it.  Get hold of the data sheets for the chips and work out the circuit before you start randomly stabbing things.  These DDMs are getting rare, and are a bit fragile electronically.  Maybe it's best to leave it to people who know what they're doing.

[Matt the Modulator]

texas instruments maths marvel i cant find any bends what so ever and speak and music also i only found one glitch but that only works when you have abused the circuit for a while mmm i mite try AND  marry them together mmm