YAMAHA A3000 FIX - PART 5, Capacitor hack

(preface)

In this page  http://www.jsigle.com/musicol/emufix.htm  , there is a detailed description of  a modification for the EMU sampler that improves vastly the encoders functioning precision..

This mod has been applied to the Yamaha A4000 too :

https://seaweedfactory.blogspot.com/p/yamaha-a4000-encoder-fix-and-compact.html   

So, I decided to go on with this hack and made a board to use it with my own sampler , according to the instructions above :

The board :

 

 

And the complete kit with cabling :

 And this is the design the board was based on, thanks to  https://seaweedfactory.blogspot.com  :

 

PROCEDURE

I decided to use the encoders’ PCB I already had installed in the sampler , which has the Alps stock encoders. They work ok, but they behave somehow not perfectly.  Remember (see my first post) , that this is a used board that I purchased from ebay to replace the old one with damaged encoders.

So, I prepared the board and the cabling (I used cables from an old broken PC which had 2,54 fine connectors on one side already).

Then I soldered the cables to the encoders PCB :

 

Next photo shows the easiest place to solder the common ground :

In order to avoid any short-circuits with the adjacent traces of the pcb, I put some electrical tape really close to the solder joints (photos below)

and also tape over the cables to fix their position on the board.

Then I taped some cable pairs on one side of the board and the rest on the other side, and put them through the Yamaha chassis holes (left and right of the encoders’ PCB mounting position) :

(view from inside):

I connected all cables to the new board and placed it on the chassis using a piece of plastic between board and chassis (we don’t want the solder joints to touch the metal chassis, right?), and fixed the assembly with double-sided tape (don’t need any screws here, Yamaha has enough screws already LOL!!)…

So, There you have it :

 

OK, time to put this on a test :

Yamaha power on ,….

……Start fiddling with the knobs,…..   

and….   ....

……..  IT WORKS !! 

I noticed a day and night improvement on the encoders precision. They don’t skip back and forth in values, they change values correctly even when I turn the knobs really fast !

And I must point out that I used the old Alps encoders, and not new! So, with new encoders AND this PCB modification, I guess the A3000 would have a completely different personality !!  J

SUCCESS !   Thank you  https://seaweedfactory.blogspot.com  for your design !