Yamaha SY35 repairs …

The Non-Hunt for Synth Parts

Yamaha SY35 Vector SynthesizerYeah, I grabbed one of Yamaha’s forgotten vectors a while back for a good price.  The SY35 is a pretty sweet-sounding instrument that’s fun to program. I look forward to digging deep into its digital soul.

The unit I got had a couple of dead keys. I also noticed a couple of keys that were hyper-sensitive to velocity, i.e. they would always sound as though you struck them twice as hard as you actually did. So I took the keyboard apart and tried to clean the key contacts under the offending keys, which turned out to be a colossal waste of a lot of time. After a bit of research, I found that this keyboard mechanism is used on a lot of Yamaha keyboards including the DX11, V50, SY55, SY22, CS6X, some PSR (consumer) keyboards, and others. With age, these keyboards will all develop these issues, but there is an easy fix. There is a rubber strip with carbon contacts that runs the length of the keyboard which must be replaced when the carbon starts to deteriorate. The part number has been superseded a few times, but the new part is compatible — Yamaha’s part number is VF83410R. Syntaur carries a rubber contact strip as well. I’m not sure if Syntaur’s offering is a genuine Yamaha part, which may or may not be a bad thing.

The other issue was a dead battery. On the SY35 this is particularly frustrating, because of the way the preset sounds are mapped. The 64 ROM patches are comprised almost entirely of dull acoustic simulations, that really don’t show what the synth can do. The synth ships with the more interesting patches stored in RAM, which is perfect, because you have to overwrite them when you store your own sounds. Seriously Yamaha, I’m sure there’s a statute of limitations on how long you can be called out for this stuff, but I don’t care. The keyboard is 20 years old and the ROM presets are abysmal.

So … here’s the issue with the battery: it’s one of those CR2032 coin cells with PC pins tack welded on, but its pin spacing is unusually short. People all over the internet seem to be asking about this battery, and everyone who has an answer seems to be suggesting buying a coin cell holder and shoehorning it in (actually there is room, but again, the pin spacing is a nuisance). In this case however, the most elegant solution is also the easiest: I asked Yamaha, and guess what? Yamaha part # VE33840R, drop-in replacement battery, in stock. I won’t have to worry about it again for another 10-15 years.

But wait, the good news doesn’t stop there. Let’s talk about prices. I’m fortunate that Yamaha Canada is within easy driving distance for me (in Scarborough, Ontario). But even if it wasn’t so close, they will next-day ship any order for $7.99. The battery cost $4.85 CAD, and the rubber contact strip $34.74. But I’ve been saving the final bit of good news until the end: They gave me a scanned pdf of the SY35 Service Manual! I’ve been unable to find a downloadable copy on the internet. But don’t worry, I won’t hold out on you. I plan to make the full service manual available for download shortly – it’s actually 4 separate files, and I’m trying to figure out the best way to distribute them together.

Two styles of horizontal-mount, solder-tabbed CR2032 coin cells.

The coin cell on the left is typical of coin cells with attached solder tabs. Notice that there is a tab on each edge of the cell. The SY35's battery requires pin spacing similar to the cell on the right. (Click to enlarge)

Details about the battery:

Yamaha VE33840R – “BATTERY SONY/CR2032-HC2H GCX1100″

10 thoughts on “Yamaha SY35 repairs …

  1. Hello there. I also have a SY35 and mine has started to reboot itself after a short time playing. I don’t know if this could be caused by this dead battery. Thanks and hope to hear from you soon.

    • I doubt very it would be a battery problem. More likely a poor connection somewhere.

      If your battery’s dead, you’ll lose your sounds when you power the unit off. But when it’s powered up, everything should otherwise be normal.

    • Hey man, if your problem still occurs, this is not caused by dead battery but by electrolytic capacitors on PSU. Change those capacitors (these are not expensive), you’ll need some soldering skills.
      I had exactly this same issue on my DX7.

  2. Hey there, I have the same issue with the battery; I actually just ordered the CR2032 battery but after reading your article I guess I need the specific VE33840R with the pins attached to it. Also is it quite a process to replace the battery, would you by any chance be willing to list a step-by-step guide on how to go about it. Also any idea where I would find that specific battery or do I contact yamaha directly?
    Thnx so much for your helpfull article.

    • I should have also mentioned that you can use a plain CR2032 with no pins attached, but you would then need to install a battery holder. These things are also only a couple bucks each.

      Since these batteries usually last at least 10 years, I prefer the ones that can be soldered direclty to the board because there is no risk of the connection going intermittent over that long stretch. But if you already have some CR2032 coin cells, and you don’t fancy the idea of doing a solder job again, then absolutely put in a battery holder.

      This is still not a job for an electronic/solder novice though!

  3. Thnx so much for the info, is it also quite easy to open it up and install myself? Im not too keen on opening the synth up and scratching where im not supposed to

    • If you have no experience taking things apart and soldering circuit boards, it is absolutely not an easy job. On the other hand, if you do, it is!

      I also do this work for a pretty reasonable rate. I don’t know where you are, but usually you should be able to find a local repair person more easily than sending it for service. Any electronics repair shop (including TV repairs) should be able to do this job for you, for less than a half hour’s worth of labour.

      If none of this works for you, and you’d like me to take care of this, let me know and I’ll contact you privately.

      • Ok thnx so much for all your help and advice, much appreciated! If I find myself struggling Ill defntly contact you. Many thanks

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