Category :Projects

Boss DR-55 capacitor change to allow use of TC4011B chips..

From a thread on electro-music forum: “The CD4011 is a bit fussy … a few years ago I repaired one of these machines with a bad 4011, and the replacement I used caused pattern writing to work incorrectly. A different 4011 fixed the problem.” “I had the same problem for long time until have found … Read more

Hohner EK 2: All sounds now working. Just about..

I spent an hour tinkering tonight..I now have all sounds working: piano, harpsichord, electric piano, bass, brass, and.. tada.. strings. Piano was a wobbly connector, and strings have a dodgy capacitor on the crescendo function (I think) Turned that off, and.. beautiful strings.. Still need to replace a load of sliders and sort out a … Read more

Hohner EK2 – First Look

I almost called it a synthesizer.. but really,  it’s not. But it IS analog (“analogue” – in English) and it has a “Strings” section. In fact, it has several “sections”: Piano (not working) Piano Electric Piano Harpsichord String (Very quiet) Strings Brass (Working) Brass Mute Bass (Working) Bass The complication here is that there are … Read more

Introducing my new Hohner International EK2 Synthesizer project..

I just bought a Hohner EK 2 synthesiser!This will be my main project after I finish the Korg Delta. I am pretty excited by this, although I know only the bass section currently works. I am familiar with this kind of technology so it’s not that scary, although I did have a Hohner string machine … Read more

EDC SR-99 Project – TC5514 memory chip replacement.

I finally got around to replacing the memory chip. I bought two from vintage planet on (Hi Senso!), which arrived very quickly. Unfortunately so did the ‘flu.. Anyway, I whipped the memory chip out using my usual Duratool Soldering kit and desoldering pump. 5 minutes max, I’m getting good at this now! I was … Read more

EDC SR-99 Project – Introduction

This may or may not be the SR-99 I replaced the battery clip on in an earlier project. There’s a video associated with that: Anyway, although it appears to work, there’s no sound (there’s none on the video either..). I’ve had it in bits, and although I can see a replaced 4011 sitting in … Read more

Boss Dr-55 memory chip replacement. (TC5501P)

This turned out to be remarkably easy! Step 1: de-solder the existing memory chip. This turned out to be an NEC equivalent of the Toshiba TC5501P. So, 22 pins to desolder using my Duratool soldering iron and tools. The desoldering pump did the job yet again, with some cleaning up of the holes. My IC … Read more

Battery Clips & Testing | Defective tc5501p ?

I have replaced the battery clip with one that doesn’t have the pp3 clip on it, to save space. I unsoldered the old one, and soldered in the new one, knotting the cable as cord relief, as per the original. I can now get the battery holder in and out easily. I also got the … Read more