Yamaha U1 Technics Silent System help

[bsharp77]

Hi everyone,

I have managed to pick up a nice 1980s Yamaha U1 with a technics silent system fitted.
Acoustically, the piano is great, however when I flick the lever for the silent system, most keys below middle C require heavy pressure to activate the sound. This makes the silent system more or less unusable. As I plan to use the piano 80% of the time silently I’m quite worried.

The module is a technics sm-zs1a.
Does anyone have any manual or any sort of info on this system? Im hoping there may be some sort of adjustments I can make or sensors replaced to bring the full silent system back to life.

If not, what other options would I have?? Would there be an option to replace the silent system at a reasonable cost? I really need it to work properly as I plan to hook the MacBook up and use Garritan CFX with it.
I got the U1 as the wife really loves the look of the full cabinet in the room, and I agree it looks stunning. The piano plays well enough acoustically....really thinking I should have just went for a NU1X though....!

Any help would be very much appreciated

[Barrie Heaton]

it could be...

• The slap rail needs adjustment.
  The prolong pick up unit in the bass is set to low

I would say more like the first. Lift the lid and look at the travel of the hammers in the treble, then the base when the silent system is engaged. See if it is stopping the hammers the same amount from the strings on both sections

Barrie

[bsharp77]

it could be...

• The slap rail needs adjustment.
  The prolong pick up unit in the bass is set to low

I would say more like the first. Lift the lid and look at the travel of the hammers in the treble, then the base when the silent system is engaged. See if it is stopping the hammers the same amount from the strings on both sections

Barrie

Thanks a lot for the swift response Barrie.
I shall check that shortly and report back!

[bsharp77]

Hi Barrie,

Thanks for the suggestions.
I’ve took the front off, but to be honest, I just have no idea if the hammers are much further away.
Here’s another strange thing though, in acoustic mode, the upper keys don’t play at all if pressed softly, however the slightest touch on lower registers produces lovely sound....the opposite problem of what I’m having with silent mode!!
There are 3 strips of felt hanging just above the hammers, and the hammers miss this on the lower register, but touch more and more the higher up you go.
There is also the odd sticking key and a lot of travel in some keys before a sound is produced.

Sounds like I need a good technician to give the whole piano a good servicing and then see where we stand....the silent system really is vital to me so fingers crossed a good service will sort everything out.

Thanks for the suggestions Barrie, I’ll report back when I get someone to gave a look.

[Barrie Heaton]

Here’s another strange thing though, in acoustic mode, the upper keys don’t play at all if pressed softly, however, the slightest touch on lower registers produces lovely sound....the opposite problem of what I’m having with silent mode!!

As its a retrofitted one, the set-off may have been set too far away in the treble it will impede soft playing.

Normal set off is 3mm on a U1 with Yamaha's own silent system it's 4 -5 any more and that is a problem for soft playing as the hammer is tripped way too early before it can strike the string

I would get a tuner in who is happy to work on Silent System myself not worked on a Technics one but thy are all the same principle

Barrie