Re: keys hit bottom

I've repaired a few of my own Technics KN keyboards and I've owned some of the pianos but I've never repaired a piano type instrument.

The bottoming out that you describe sounds like weak (or broken) springs or worn foam or felt. Hopefully it is the foam or felt because that should be relatively simple to repair. If it is the springs then you could swap springs from keys that you rarely use (maybe from the very top or bottom of the keyboard).

This is assuming that the keys 'sound' properly when you hit them. If they don't then it could be the silicone-graphite contacts and you would not be able to source these. As yours is an early piano then possibly the contacts are the same for every octave, in which case you could swap with octaves you rarely use.

We don't have the service manual for the SX-PX71 (1992) available but we have a Service Manual for the SX-PR40 (1988) available in the members area. The mechanical principles are probably fairly similar. There are probably felt and foam bumpers in the key bed. Amazon and eBay are good sources for various self-adhesive foam strips. Felt, you will probably need to cut and glue.

Hopefully another member or visitor might help. If you come across a suitable manual please share it with us. I have also asked my contacts whether they can help with this manual and if I can source it I'll be in touch.

Several websites are selling the service manual for around $5, I don't publicise these sites but I realise that these manuals can be difficult to come by and I would use one myself if I needed a manual that I couldn't find elsewhere.

As with any electronic equipment, you should be confident and competent before attempting any repair yourself and only you can assess that.

Good luck and let us know how you get on!