[sdiy] Kawai/Teisco 100p

[Rutger Vlek]

Hi all,

Somehow I didn't get the mail from Tony at first, but in the reply of Roman I can see what he wrote, and had a look at the picture. It's exactly what I already guessed. The transistor was added later. The picture shows the thick red and smaller orange cables to the aftertouch bar to be intact. I wired the 100p I have here in the same way, and found out aftertouch works, but not enough. I don't dare pressing any harder and the effect is audible but minimal. Certainly not how it was intended. Perhaps there's a fault in the scanning circuit, or the carbon rubber is worn such that it doesn't conduct as well as it did. It looked really good and clean, not dried. But perhaps the wear and reduced conductivity effect can't really be see by eye? I'll probe the scanning circuit tomorrow and see if I find defect, if not, I'd like to hunt for a replacement of the carbon rubber. I suspect it can still be obtained somewhere. It seems rather generic...

Rutger

On 2 jun 2018, at 16:52, Roman wrote:

> Adding a transistor on aftertouch was the first thing I did on my JX8P to bring it back to life. It was quick easy fix, and although not perfect, because the rubber was not evenly worn out across keyboard, it made aftertouch accessible at all. Adding to that European transistor as Tony pointed out clearly indicates that it was some kind of mod added by previous owner. Although made in wrong way since you say it doesn't work anyway.\
> 
> Roman
> 
> Dnia 2 czerwca 2018 14:06 Oakley Sound <oakleysound at btinternet.com> napisał(a):
> 
> Two thoughts:
> 
> I don't remember mine having an extra transistor in the aftertouch
> circuit. It was a few years ago and I don't have it now to check but I
> worked extensively on the unit and have no memory of an additional
> circuit in there.
> 
> BC413 is a European transistor number and I don't think you'd find one
> of those in a Japanese made synth from the 80s.
> 
> There's a photo of the guts of one here:
> 
> https://2.bp.blogspot.com/-SRZ4fTJdjJg/VZgaRcvLWyI/AAAAAAAJsaA/FVJmyBxc16c/s1600/8.jpg
> 
> Tony
> 
> www.oakleysound.com
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