YAMAHA A3000 FIX

I recently bought a YAMAHA A3000 v2 sampler from ebay, at a fairly low price, which was stated as untested. So, I thought that I could fiddle with it and fix it.

Reasons I decided to get it were :

1.  When the A3000 appeared in the 90’s, I drooled , and since then I always wanted one of those, but it was really expensive for me, to buy it new…

2.  I recently found out that even if it won’t be used as a sampler (soft samplers are faster to use and easier), I could use it as a realtime FX processor AND utilize the front knobs to fiddle with its excellent filters in realtime ..

Finally, I got it in my hands, and these issues I found out:

a. )  One button in the right panel is not working (a tact-switch needs to be replaced, no biggy.)

b.)   The front 5 knobs are not working as they should and also are very very wobbly. When I disassembled the board I found out that the encoders were officially destroyed.

c.)    It doesn’t have neither a SCSI board or the multi-outs option board (I knew it in advance, but the SCSI I don’t need, and the optional board, well.... it is optional!!)

Searching through the web, I discovered that the A3K encoders issue is quite common, and there were some fixes for their erratic behavior:

https://todbot.com/a3k/knobs/  : deals with the improvement of the encoders erratic behavior (IF, of course they are in good condition, which in my case I can’t say that they are  😞  )

http://www.jsigle.com/musicol/emufix.htm  : this is a modification that improves vastly the encoders functioning precision (somepeople did this mod and saw an improvement).

I haven’t applied any of these techniques yet to my recently bought A3K, because I discovered something else, too: 

the encoder board has lifted copper traces where the pins of the encoders go, meaning that the previous user was most of the time using the problematic encoders with angry force. So each time the encoders’ switches were pushed hard, all the push force was transferred to the pins on the board..

Looking at some mods concerning the A4K at  https://seaweedfactory.blogspot.com/p/yamaha-a4000-encoder-fix-and-compact.html , I saw that this is a design flaw from Yamaha, that was apparently fixed in the later model, the A4000 : The encoders in the A3K  were NOT bolted to a support metal plate with their respective washers and nuts like in the A4000 (see pic below), so any push action on the encoder would be transferred directly to the board (hence the lifted copper traces at the encoders’ pins soldered points)…

So, i decided to fix this also, for a thorough job.

Anyway, let’s break down to it. My repair procedure will now be as follows:

1.)   Find new encoders and replace them.

2.)  Fix the board (with a soldering iron) or find another used board in better shape (which I did)

3.)  MAKE A CUSTOM METAL SUPPORT PLATE TO BOLT ON THE NEW ENCODERS

4.)  Replace the bad tact switch at the right panel board (OR REPLACE THE BOARD).

1. ) &  2.)  :  ENCODERS REPLACEMENT  -  BOARD REPAIR :

The stock encoders are ALPS EC11E15244.. (as described in the link https://todbot.com/a3k/knobs/ ), and it is also written  in the Yamaha service manual schematics.

(The service manual can be found at  https://elektrotanya.com/yamaha_a3000_sm.zip/download.html)

After a lot of searching, I found these encoders readily available:

1.)  ALPS EC11E15244B2  (same specs 30-detent-15 pulses with switch)

2.)  BOURNS PEC11L-4220F-S0015  (it seems to me that this is an excellent replacement to the ALPS item, and I have read some good reviews concerning the quality of these Bourns encoders).

3.)  ALPS EC11K1524406  (difference is the increased turning torque, I might pass this by….)

4.)  Alps EC11B15244A7

After reading the encoders’ datasheets, i decided to go first at the Bourns PEC11L-4220F-S0015 (which is stated to be “audio-grade”) and then at the ALPS EC11E15244B2 .  Actually , I think I will buy both types and fix 2 boards (the one I have, and the second one I purchased which seems to be in a better condition).

The board with the encoders in question is the Yamaha XS-548, and I found one very cheap, but the fix will have to wait for now, since I haven’t received it yet………..

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3.)  :  METAL SUPPORT BRACKET :

I have made the design and found support points to mount this metal support, but I have yet not made it… (I am currently awaiting for a Dremel tool to arrive, which will make the construction easier and more accurate..).

My draft design is something like this:

If you bolt the encoders through the metal-support plate's holes with their nuts & washers, then everytime you push the encoder’s switch, the push force will be transferred directly to the metal support plate and NOT to the board itself, thus protecting the board's pin connections and copper pads.

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Anyway, all of the above is just my plan, as soon I get the used board and the new encoders in my possession.

I will post the whole procedure, when I complete this project. 

I just had to share this to all A3000 owners, so this might help you prolong the life of this excellent and features-rich sampler  from Yamaha.

Oh well, nobody is perfect, and Yamaha fixed the issue with the encoders support with the new model (the A4K), so they know better.

I will keep you all posted.

Regards, and keep on playing music !!


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--> Update :  https://synthnitz.blogspot.com/2019/05/yamaha-a3000-fix-part-2.html 


--> Update :  https://synthnitz.blogspot.com/2019/10/yamaha-a3000-fix-part-3-final-maybe.html

 --> Update :  https://synthnitz.blogspot.com/2020/01/yamaha-a3000-fix-part-4-new-encoders.html

 --> Update :  https://synthnitz.blogspot.com/2020/02/yamaha-a3000-fix-part-5-capacitor-hack.html

 --> Final Update :  https://synthnitz.blogspot.com/2020/02/yamaha-a3000-fix-part-6-conclusions.html

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