Help with AMSTRAD CKX-100 keyboard synth thingy -

[dirtycircuits]

OK, I've been happilly bending this machine for a few days now. Got some incredible sounds from it, and  I am amazed at how awesome it sounds now compared to it's cheezy stock condition.

Sadly I had an accident - I forgot to un-plug the power from the machine before soldering on the last set of switches directly to the legs of the IC.  Now it seems to be permanently circuit-bent. I've removed all the bends, checked closely for stray solder, and thoroughly cleaned between and underneeth the pins of the IC, but have had no luck in restoring the machine to UN-bent condition.

Do any of you good people know of a way to reset the machine? Is there a way to re-boot the chip, or is it possible to replace the chip with some other equivilent?

The drums appear to have completely vanished, the accompanyment is well out of tune, and the patches are all st-u-tt-e-ry. In fact it sounds just like one of the bends I was experimenting with (except that it's permanent!)

I'd be gutted to have to abandon the machine, as they're quite rare I gather...

thanks

[Gordonjcp]

Well, from a description on the tablehooters site there's a CMOS RAM chip with a big electroytic backing it up.  Try shorting across the chip's power pins for a few seconds to discharge the cap.

[dirtycircuits]

Well, from a description on the tablehooters site there's a CMOS RAM chip with a big electroytic backing it up.  Try shorting across the chip's power pins for a few seconds to discharge the cap.

Thanks for the advice Gordonjcp, sadly it looks like I've killed the machine.... :-((

On the bright side though, I've managed to buy another Amstrad ckx on ebay, so they're not quite as rare as I'd thought. Hopefully I can just swap the switches straight over and consider the money spent on the new CKX as a 'stupid tax'. At the very least I've learned an important lesson - Un-plug the bloody machine before soldering into the chips!

Any-hoo - - thanks again

[dirtycircuits]

Hello again -

work is going well with the new machine. This one is actually slightly different inside. Bits of the track are cut and contact wires are soldered across the board. Its stinks of solvent as well, but the bends all work the same.

Question though - I can't find a pitch resistor (licking fingers and touching board doesn't seem to alter pitch at all), but there is a big silver component, which I presume is a crystal.

Is there a way to modify it so that I can pitch-bend?

If not, I can build a new clock oscillator with a 555 or a CMOS and use this to pitch-bend the machine, right?

How would I find the correct part of the IC's to attach the new clock oscillator......is there a way to locate this without using an oscilloscope???

Many thanks again............

[Gordonjcp]

Remove the crystal and inject the oscillator signal at one end or the other.

[dirtycircuits]

Remove the crystal and inject the oscillator signal at one end or the other.

Thanks for the advice, I should have been a bit clearer with my question though -  The problem I'm having is that if I inject the new oscillator at the (removed) crystal, it also alters the tempo as well as the pitch, which is un-desirable for my needs.

Specifically there are 2 large chips in the machine, the first chip seems to be related to the drums, and by switching the pins here I am able to 'bend the drum sounds. The other chip seems to 'bend the synth sounds (piano, flute, etc).

I know very little about digital technology, -  but I'm guessing that each chip receives clock oscillator on a dedicated pin? If I can find these pins for each chip then I'm hoping that I can alter the pitch of the sounds without affecting the tempo......... What do you reckon?? Am I barking up the wrong tree here?

After killing my first Amstrad ckx I am a little scared of playing around too much with this one. I figured that if taking a little time to ask an expert saves me from the greif of another dead machine then it'll be worth the wait!

So............... how would I go about finding the correct pins, and what precautions can I take to avaoid damaging the machine?

And apologies for my poor written communication skills

Thanks in advance for advice