Casio PT-10

[Psycho:Active]

I got this for £1.50 last sunday at a car boot sale, worked fine, now I've had my hands on it, it doesn't work fine.. I'm unsure of exactly what went wrong.. it might be that I used a large soldering tip to solder fine points on the IC, but pff.. it was good while it lasted.
So it's not so much to waste, and possibly if someone could give me tips as to how to diagnose and possibly fix the keyboard (it was dying already though), I'm posting some pictures and tips about what I did to the PT-10.

Overview of bends and cutting

Above you can see roughly what the keyboard looks like with the bends. You can see also that I cut the casing to get to the IC. My cosmetic restoration plan was duct tape.
You can also see the pressure points for the keys, as I took out the plastic keys temporarily so I could access the PCB.
I had to keep the front part of the case on as the on switch relies on some kind of metal-pressure-sliding switch type device.

A basic overview of the bends I found:

• The two potentiometers in series are a clock bend, making it go slower. I didn't know what was the best pot to use, tried a few, and just put in two for extra/unnecessary control
• The red switch altered the percussion on the demo, making it more broken and thus better
• The top switch with black and red wires is connected from about the 3rd bit down from the top solder point on the IC and caused a type of distortion. Note:The soldering seen (and later in a better picture) is not in a way which allows it to work
• The switch on the bottom right with the green and grey wires activated a different, more powerful type of distortion. As you can see, the soldering on the IC was slightly sloppy
• The switch below the top switch did something but I cant remember to be honest. If it wasn't cool then I wouldn't have soldered it

Below are some closeups of the PCB taken in sections from left to right:






A few notes, tips and comments

With the PT-10 I experienced the same problem as I did with the only other small Casio I've had a look at bending, which was battery placement. Having the back case on allows for the 4 AAs to be securely held in sequence, however with it being handy having the back off incase anything needs to be accessed, the damn batteries won't stay how you put them, and will therefore not power the keyboard. To solve this I got a 9V battery and clipped it to the approperiate battery connections, as shown below:


A problem I had was accessing the full PCB whilst retaining power to the keyboard, due to the switch types as mentioned somewhere above. It led to me breaking off parts of the front casing to access the IC. If anyone can tell me a better method of getting to it while retaining power, please let me know

What I experienced once I'd clumsily stabbed the IC with solder and wires was a change in the function of the keyboard. If I were to anthropomorphise it, it's like by attacking its brain I lowered its IQ, as it got slower, more unpredictable, and it didn't play rhythms any more, merely the demo and altered, semi-working keys (played correct-ish notes, but not always). So I'd say be careful and use a fine pointed soldering tip when going near the IC.

If anyone can give me advice as to how I can ressurect this PT-10 (more through voltmeter than prayer if possible), then I'd greatly appreciate it, and I'd post a video in this thread if I actually got it to work.

I hope this sheds a bit more light on the PT-10. There are some interesting bends in there, with the ability to play only the percussion or melody on the demo with approperiate connections. There's a video on youtube of a well bent 'sCat' PT-10 which puts any of the bends I achieved to shame. Particuarly as it evidentally works. However I'm pretty sure it doesn't come with a guide. And this one does. A guide to break it. (But hopefully this will prevent more permanant breakages)

[Circuitbenders]

A problem I had was accessing the full PCB whilst retaining power to the keyboard, due to the switch types as mentioned somewhere above. It led to me breaking off parts of the front casing to access the IC. If anyone can tell me a better method of getting to it while retaining power, please let me know

Solder a jumperwire across the switch so its permanently on.

[Psycho:Active]

Would that work with this kind of switch?
You can see the type of sliding metal at the bottom and what it presses against at the top of the picture.

[Dylan]

Would that work with this kind of switch?
You can see the type of sliding metal at the bottom and what it presses against at the top of the picture.

I'd relaly like to know about this too, I wanted to try it with my SA2.

[Circuitbenders]

Well, if theres an on/off switch then its should be fiarly simple to trace back the points that would be connected when youi put the switch in the on position, and just wire them together to bypass them so its permanently on.
Bear in mind that most on/off switches just connect two contacts and so bridging these points will turn the thing on.

[Gordonjcp]

Also, don't forget that four AA batteries is six volts and a nine volt battery is, well, nine volts.  This is actually reasonably likely to damage stuff, unless the 9V battery was pretty flat to start with.

[Psycho:Active]

Sorry to be so explicit in my ignorance, but where exactly should I cut and solder the traces?



Also, true about the 9v battery, it probably wasn't the best idea, but I had no battery holders for 4AAs so it was the next best thing, and it didn't blow it up, so wahey.

[computer at sea]

No need to cut any traces, hoss.  Just wire a jumper across.  Use whatever tool you find your bends with and probe that area till you find a connection that turns on the keyboard then wire a jumper between those two points.  Follow the traces back from where you've labeled "play" on your picture and you should find the spot.

[raygunduck]

hi, anyone know how i can get an (output) from the drums? it's possible get an out for the keys and an out for the drums? thanks (i have created a new topic.. please reply on it)