My friend, who's an electronics boffin
(besides being a busy musician) finally had time to look into my shaky
NL3s.
So here's what we found. (cheap, working and easy fix
follows!!)
First of all we needed to reproduce the failure. A
vacuum cleaner did the trick. When (turned on and) plugged into the same
socked, the Nord Lead rebooted consistently :-)
It turns out there
is a slight design flaw on the PSU board of the NL3. The board delivers
12V (for analog bits), 5V and 3V3 (for digital bits and the 100s of
LEDs).
All three supplys are build in a very standard way, however the
3V supply lacks the reservoir capacitor that you'd usually find. The
capacitor helps smoothing the voltage, and also counterworks 'brownies' on
the mains supply. The PSU actually delivers 3V ok-steady, but measuring
before the final voltage regulator reveals a significant voltage
ripple.
The fix we suggest below made both my Nord Lead 3s
hoover-resistant, and they haven't been spontanously resetting since. The
fix is quite easily implemented, very cheap – and at you own risk of
course.
THE FIX.1. Open the NL3
2. Locate
the PSU board, it's right side of the cabinet. Looks like
this:
3.
Locate the 3V voltage regulator
4.
Mount a 2200 µF 10V electrolyte capacitor across the input side of the
regulator. Solder the capacitor legs directly upon the legs of the
regulator. Important to get the polarization right. The component is a
mere 1€ / 1$. Doesn't need to be excactly those specs, similar or higher
capacitance values should work ok, but it needs to handle at least
10V.
5.
Close up and enjoy your improved Nord Lead 3.
// Henrik Munch &
René Thalund, Denmark