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………..
…………………………………………..
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.
…………………………………………..
…………………………………………..
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
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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
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