Maybe if I had heated the original solder more it would have produced a better result. Or perhaps I need to fully clean off/ remove all the old solder before re-soldering?

If you look at photo and have no new ideas,

or my suggestion above seems misguided,

then my question is— can I send Yamaha the pc board for repair? Would be a lot easier and less expensive than sending the entire keyboard. Assuming the problem is on that pc board somewhere.

Big thanks,

Thanks for the picture, it reveals all. The area around the C#5 part of the circuit is badly corroded. In addition to the obviously affected solder joint (which, by the way, appears to be for D5, not C#5), the foil traces in the area appear “lumpy”.

After a pc board is etched, it’s coated with solder mask (https://en.wikipedia.org/wiki/Solder_mask). The appearance of the coated foils should be smooth. The lumpiness that’s evident in the picture typically indicates corrosion has occurred under the coating. It’s likely that there is loss of continuity in the affected foils.

This sort of damage can be easily repaired by a competent technician. The solder mask is gently scraped off to reveal the copper foil traces, or the lack thereof where corroded. Thin wires are then soldered to jump over any breaks that are found.

Of course, replacing the pc board would also resolve the problem.

Wow do you know your stuff or what!

I’m not sure the “lumpiness” isn’t just a photo optical distortion. I don’t recall it looking anything that bad in reality. In this photo it looks really bad.  Hmmmm…

Re which note it is, I thought the D on the far left of the three solder joints stood for “Diode,” since they all seem to have a “D” on that solder joint #3. (see keys on either side of C#). Plus it looks like it says D6 - D15 or something. Whatever, that was the one I re-soldered. The Ohm meter worked on all foils, for wjat that’s worth.

At any rate, scraping of the mask, finding breaks, soldering them… whew, I think I hit the wall on that one.

Wonder if Yamaha would throw me a pc board for free since it’s been only 1.5 years in an AC studio. Or, what they might charge to send me one.

What do you think I should do?

BTW, you have been AMAZINGLY helpful. I couldn’t have asked for more. And all the time you took to answer so carefully. Wow. I can’t thank you enough.

Really.

PS Do you moderate this blog? If you don’t you should!

Thanks, again.

Winky - 22 July 2015 06:59 AM

Wow do you know your stuff or what!

Thanks. I have lots of experience, too much to detail.  :-)

 

Winky -

I’m not sure the “lumpiness” isn’t just a photo optical distortion. I don’t recall it looking anything that bad in reality. In this photo it looks really bad.  Hmmmm…

Well, there are only three possibilities for the failure of that one key to sound.
1) Bad contacts - but a new contact strip didn’t help, and apparently neither did cleaning of the board area.
2) Bad diodes - but ohmmeter testing indicated they’re OK.
3) Discontinuity of foil trace(s) only in the immediate area (since all other keys work).

 

Winky -

Re which note it is, I thought the D on the far left of the three solder joints stood for “Diode,” since they all seem to have a “D” on that solder joint #3. (see keys on either side of C#). Plus it looks like it says D6 - D15 or something. Whatever, that was the one I re-soldered. The Ohm meter worked on all foils, for wjat that’s worth.

There are two diodes per key location. Although not every position on the board might be labeled this way, typically the first (left to right) “D” does indeed designate a diode, and is immediately followed by a one or two digit reference number. There can then be a hyphen, followed by the key reference. The one at the end of the board says “D1-C#5” - it’s the first diode, and for the C#5 key. The one where you soldered says “D3-D5” - it’s the third diode, and for the D5 key.

 

Winky -

At any rate, scraping of the mask, finding breaks, soldering them… whew, I think I hit the wall on that one.

Wonder if Yamaha would throw me a pc board for free since it’s been only 1.5 years in an AC studio. Or, what they might charge to send me one.

What do you think I should do?

I wasn’t necessarily suggesting that you do the repair yourself - any skilled technician could do this. It becomes a question of the cost of the repair versus other options.

It used to be that soldering was done using a rosin flux. To remove that type of flux requires solvents that are not usually environmentally friendly, but the flux is relatively inert once the joints cool and it often can be left in place. Modern practice is to use a different type of flux that can be washed off with just water, but that flux must be removed because it is hygroscopic (absorbs moisture from the air) and then becomes active and can cause corrosion.

So, there’s a possibility that the defluxing of the board wasn’t done sufficiently, and that’s what caused the problem. If Yamaha will see it that way can only be determined by presenting the situation to them.

Best of luck in getting this resolved.

I have been following this post very carefully because it relates closely to the situation I find myself in. I have a Motif XS6. Recently I started having problems with three keys in the bottom octave: E, G, and A#. I did the quick fix of disassembling the keyboard and cleaning the contacts as well as the carbon coating on the plastic buttons, it completely solved the problem with the G key but the E and A# remain completely unresponsive. It should be noted that the G was producing some sound but was unpredictable with it’s key velocity whereas the E and A# just went completely dead. I also live in Hawaii (island of Oahu) and we are pretty much on our own out here. Just wondering what happened with your situation, and hoping that I can gain some insight on how to fix my situation. That being said, this forum and specifically this thread have already been a huge help! Thank you!

ecap12 - 02 September 2015 05:54 PM

[...] I have a Motif XS6. Recently I started having problems with three keys in the bottom octave: E, G, and A#. I did the quick fix of disassembling the keyboard and cleaning the contacts as well as the carbon coating on the plastic buttons, it completely solved the problem with the G key but the E and A# remain completely unresponsive.[...]

Welcome to the forum.

Although there is a certain sharing of circuitry between all E and A# keys, and between G and A# keys, problems with just E1, G1 and A#1 have to be due to bad contacts, diodes, copper foil, or solder joints in a limited area. (For the XS6, that would be on the MK61L board.) Often careful visual inspection will reveal a problem.

It would definitely be interesting to find out what the outcome for Winky‘s MOX was, although it may or may not be directly applicable to your XS6.

I found a repair technician on Oahu that sounded very knowledgeable who said he was fully able to do the repair. Very nice guy. I haven’t been able to ship my keyboard over there yet because I’ve needed to use it for performing—minus one note, of course.

His name is John Ross. Telephone is 808-255-2555. 1339 Lunalilo Home Road, Honolulu. 

Keep us posted.

I tried to reach John several times with no luck. Looks like I’m still on my own out here. 5PinDin if I opened it up again and took a picture of the problem area do you think you could check it out and let me know if it’s something I might be able to fix on my own?

ecap12 - 15 September 2015 06:08 PM

[...]5PinDin if I opened it up again and took a picture of the problem area do you think you could check it out and let me know if it’s something I might be able to fix on my own?

I can try, but no promises.

Would you feel comfortable doing something with the XS disassembled and the power on?

Ok I will open it back up. And yes I feel comfortable troubleshooting with the XS disassembled and powered.

ecap12 - 16 September 2015 02:52 PM

[...] And yes I feel comfortable troubleshooting with the XS disassembled and powered.

OK. If you have any foam swabs (similar to cotton swabs) and some aluminum foil…
Wrap some foil around the foam on two swabs, making sure it’s firmly attached. After removing the appropriate key contact strip, you can use the foil-covered swabs to check operation, touching them to the p.c. board contact areas where the carbon-coated buttons of the contact strip normally make the connection. The shorter the time between connecting each of the two contacts, the higher the velocity - start with a key that’s functional so that you can determine how that works. When you know how to trigger a note, try it on a “bad” key position. If those positions work that way, then the contact strip is the problem. If those key positions still won’t function, then we can look further.

If anyone is wondering why foil-covered foam swabs, it’s because they’re soft enough to minimize the chance of damage to the contact area of the p.c. board.

Note to those considering doing the above:
If you don’t have experience working on electronic equipment, especially with the power on, leave such work to someone who does.

Ok, so I finally got around to trying this technique, and was unable to get any sound from the two broken keys, so I guess the contact strip is not the problem… Any other ideas? Would it help if I sent over a picture or video of the problem area?

ecap12 - 02 November 2015 09:01 PM

Ok, so I finally got around to trying this technique, and was unable to get any sound from the two broken keys, so I guess the contact strip is not the problem… Any other ideas? Would it help if I sent over a picture or video of the problem area?

Sometimes in areas of high humidity, especially coastal regions with “salt air”, there’s damage to printed circuit foil.

Concerns a Motif XS6, see the linked pictures in this thread:
http://www.motifator.com/index.php/forum/viewthread/475942/

You could attach a picture.

I had the same problem happen to the middle A key just last week. Probably due to high moisture here in Florida. The circuit board underneath the key bed is very inexpensive for an XS7 model as well. Hope you were able to fix your synth!