Sunday, March 06, 2016

Casiotone CT-370 Major Minor Key Repair

My Casiotone CT-370 had a problem with a loose power jack connection.IMG_3058IMG_3061
I desoldered the old one and soldered in a new one. It was pretty routine. This blog post isn’t about that.

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Kitties! Again, not what this post is about.

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I discovered that the F sharp (or is it G flat?) key has a problem. It’s loose and broken. Not really qualities I look for in a piano key. Or any key.

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That foam is everywhere and is all nasty. But it’s a cheap keyboard and I’m not going to remove all the foam.
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I found I had to pry this white strip away to remove the key, and the two white keys on either side needed to be removed as well.
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Broken hinge end. I tried gluing it but it would immediately snap. It’s under a fair bit of force from the spring.
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Just not enough meat to use adhesives.
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Cleaned up.
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Some suitable steel was cut.
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Forming the channel with an arbor press, vise and a 1/4” square toolbit.
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The channel.
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Drilled a hole for the post.
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The spring fits but I had to squeeze it slightly oval to get it to bottom out.
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Some washers shim up the channel because of a step down after the post.
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Two brass #2 screws fasten the channel to the key. I sawed a slot and widened it with files until it approximated the form of the broken bit. Some repairs are best done by eye.
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That foam…nasty.
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It fits! It came out surprisingly well for a speedy hack repair.

Monday, February 22, 2016

More Audio Projects

I put the Gakken SX-150 MKII into an enclosure and broke out some of the ins and outs.
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Some bad video of the bad noises…

Flush with hubris I added MIDI out to my Volca Beats (did the capacitor mod too).
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Used my audio breakout box to test the output of a cheap thrift store metronome.

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And used the breakout box to test my 1/4” mono cables. IMG_3148
But then I needed to make an expression controller for my Korg DS-8 and the breakout box failed to be useful because the Korg uses a TRS cable for the expression controller… I’ll be making a V2 breakout box soon that uses TRS jacks instead of TS.
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So I made up a box with TRS out for the expression controller. Just a box with a two switches (one momentary) in parallel, hooked up to a TS jack for the damper pedal function, 100K pot hooked up to a TRS jack (connect ring to wiper of potentiometer, tip and sleeve to either end of the resistive element). Two other momentary switches wired to TS jacks for the prog. up/ass. and down pedals, no point really connecting them but hey). You can already control tremolo and wah with the joystick, but that always springs back to center, this pot allows you to set various values. Damper pedal allows more sustain. IMG_3169IMG_3170

You can assign various functions to the expression and accessory switches.

Bad noise video:

Anyway, having fun I suppose.

Thursday, February 18, 2016

Yamaha RY20 Drum Machine

Bought this on Ebay for $20 as it was not functioning.

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And it wasn’t

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But when I turned it on I noticed that the display did change subtly.

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So I took it completely apart and couldn’t find anything wrong. Then I decided to be smart and googled it…turns out in some modes it gets stuck and needs a factory reset (-1 and +1 keys held down when powering up).
It sprang to life but did display a low battery message…

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So I did the same thing as on the Korg DS8, soldered in a PC battery holder.
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Yay!

Monday, January 18, 2016

DIY Fake Modular Synth From Monotron Duo and Monotron Delay

I’m slowly working on a pile of unfinished projects from last year. I had played a little with some of the patch points on the Korg  Monotron Duo and Monotron Delay pocket synthesizers. DSCF3867DSCF3869 I had already soldered wires onto the pitch/Vrib connections and ground points. I should have left them on and spliced but… DSCF3871 I picked up this case at the Habitat “Restore” for a couple of bucks.DSCF3876 Some layout work.DSCF3882 I would need to assemble the Monotrons after the bottom shell was screwed to the case so I drilled holes through the battery compartment for screwdriver access.DSCF3885 Lots of wires were cut. If I could do one thing differently I would have used lighter gage wire. I used 22 and I think 24 orlighter would have been easier to deal with.DSCF3886 Solder, solder, solder.DSCF3888 The Vrib connection on the Monotron Duo did not survive desoldering the old wire, so I had to snake a tiny wire (ethernet cable wire, which is what I should have used for everything) around and solder it to the ribbon ZIF socket.DSCF3890 Holes drilled.DSCF3891 Snaking wires. The bottom half of the monotrons are attached to the case with #4 flat head socket cap screws.DSCF3894Held with nuts. DSCF3896 Easy? It takes a lot of care to get the wires massaged into place so the cases can close.DSCF3898 It’s important to label the wires.DSCF3901 #$@%!!!! Oh well. If I end up taking it apart I’ll put the battery covers back on.DSCF3905 Now to solder all the jacks and ground wires. This took a long time and was very boring.DSCF3907 I soldered wires to the battery terminals on both and terminated with crimp connections so I could attach AA battery packs or in the future wire it for a 3V wall wart.DSCF3908 All the grounds connected. I used hook crimps and I wish I’d used eye crimps.DSCF3910 DSCF3913So now I have the two Monotrons mounted and can patch them at will.

As you can hear, it’s sort of annoying but shows promise.