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Old 21st Nov 2017, 10:58 am   #24
kevinaston1
Hexode
 
Join Date: Aug 2014
Location: Featherstone, West Yorkshire, UK.
Posts: 386
Default Re: MIDI keyboard fault

Every type of keyboard note or MIDI error I have had has been due to noise in the electronics, or the power supply.

I have had crystals way off frequency, crystals that jitter, etc. Power supplies that have HF noise on them, regulators that oscillate – every thing you can think of has come up.

MIDI is a very simple serial interface running at 32 KHz WITH NO ERROR CORRECTION. Each message is 8 bits long; the first bit denotes the message type, whilst the remaining 7 bits denote the value, from 0 to 127.

Although it is a simple serial interface, it was brilliant in its inception. At the winter NAMM (National Association of Music Merchants (USA)) show in 1981, the Roland Electronics chief, Ikutaro Kakehashi met with two American synthesiser giants, Tom Oberheim (Oberheim Electronics) and Dave Smith (Sequential Circuits). Together, they hammered out the basis of the MIDI interface, and it was immediately taken up by all the other manufacturers. How is that for friendly international cooperation?

So, check the power supply for noise, hum, low voltage etc. Check the processor data for noise etc; check the MIDI data for noise. Look carefully and you will find it.

Kevin
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