Sat Jun 27, 2020 5:49 am
Hi Ed,
Yes, the original flat brass springs are still in place. I've been told that there is a way to lighten the touch, but it involves a bit of work.
If your second-touch springs work like mine, the flat brass springs have a strip of steel attached to each. At rest, the steel strip is drawn towards a long felted magnetic strip which runs the length of the keyboard. A screw let into a hole drilled into the underside of the key body strikes the spring to create first touch (with a separate set of coil springs on the key tails providing the tension on 1st touch. Pressing the key harder causes the screw to push down onto the flat brass spring. At first the flat brass spring flexes slightly - generating top resistance and gently lifting one end of the steel plate off the magnet. As the key is pressed further the point is reached where the magnetic grip is overcome. The free end of the spring lifts off the felted magnetic strip and allows the key to fall further into the second touch depth. A long felted non-magnetic metal bar running across underneath the keys halts the travel of the flat spring. Releasing the key allows both the flat spring and the 1st touch coil spring to send the key back to the off position.
The top resistance of second touch is provided by the magnet. To lighten the second touch top resistance it's necessary to weaken the magnetic force. This is apparently possible if a thin spacer, such as another layer of felt, is added between the magnetic bar and the steel plates attached to the flat brass springs. This holds the steel plate further away from the magnetic bar, thus reducing the magnetic force slightly, thus requiring less pressure on the key to break the magnetic grip.
I haven't tried this on my keyboard, so this is as yet unproven. Yesterday I looked closely at the assembly, and even unscrewed one of the flat brass springs, and this allowed me to see exactly what needed to be done and how. Ideally if I was to do this to my keyboard it would have been good to do it right then and there, before reassembling the console. However this would have significantly delayed the reassembly process and I'm running out of time for this stage of the project. I decided therefore not to attempt any lightening of second touch just yet. I'll use it as it stands, and give myself time to get a feel for it, before embarking on any further changes.
I hope this advice is of use to you. It doesn't look like a difficult task in itself, but it would certainly be time consuming and fiddly to do - and of course you'd need to take your console apart first in order to gain access, unless you can remove a board from underneath the lowest manual and operate from below.
Also, bear in mind that my comments are based upon the current structure of my keyboard, in which the original key contact assemblies have been stripped off and replaced by the very compact HE sensor circuitboard. I only had a quick look at the old contacts before I sent the keyboard off to be rebuilt, and from that glance I can't recall to what extent the original contact assembly would get in the way of this work. With my setup there's no trouble whatever in gaining access, but it could be possible that the original contacts may pose a physical obstacle - I just don't know.
Andrew