Yamaha Clavinova CLP-411 - no LED display, no sound

Hi,
Our beloved Yamaha CLP-411 just stopped working recently. When turning on, the LED power indicator (front left of the piano) is ON. However, the LED indicators on the main panel are not lid at all, and no sound when pressing the keys.
I removed the piano top cover and checked inside, the transformer still worked and supplied 18V to the main circuit board (marked as YAMAHA XP616) but did not have the service manual to check further. Could someone please kindly advise what to do to confirm this board is faulty? Many thanks in advance.
Regards,
Tim

The XP816 board is the power supply, and the next thing to check would be to see if that board is sending the correct voltages to the rest of the unit. It looks like there should be +5, +9, and +8 volts DC coming out of it, and it is possible that one of those is not being supplied. (You should find these voltages on the connectors that feed the other circuit boards.) If one of these voltages is missing or wrong, that board will need repair (or replacing).

If the power supply is outputting those voltages correctly, then it gets much more complicated, and will require some pretty serious diagnostic work to find the problem.

Thanks a lot for the info, Sam. Will give it a try and let you know the outcome. Meantime, do you know where I can order this board and how much it costs? Thanks

Unfortunately, the power supply and main boards for the CLP-411 are no longer available from Yamaha, and we do not have used boards available. The good news is that, if it is a power supply issue, it is likely repairable and won’t require any proprietary (and thus potentially obsolete) parts.

If it is a main board issue, you may end up spending more to repair it than the keyboard is worth.

Appreciated for all the help, Sam.

Just did a thorough check. Unfortunately, the power board XP616 worked fine and supplied the voltages to all other boards. I checked the power on the connectors and also the ICs on the main processor board XR586, it received the voltages correctly. Also inspected the board closely to see any physical damage or burn marks, it looked OK too. Looks like one of the ICs on XR586 has been fried from the inside.

One thing I noticed was that after putting the board back in and powering up, the LEDs on the main panel flashed then went off. Is it possible to identify the faulty IC from the symptoms e.g. no LEDs on the panel, no sound?

Nevertheless, may be it’s time to let it go and buy a new piano :-). But for us, it’s such a waste to discard such a beautiful and beloved equipment.

For reference, here are Yamaha Clavinova CLP-411 parts:

  • XP616 PU40D2
  • XS339 AN
  • XP840 JACK
  • XR586 DM
  • XR606 JACK1

Smartufo, if you’re still here, how did you get the top of the Clavinova off. The chipboard bottom of mine is screwed on but also stapled under the keyboard. I’m tempted to drill out the staples but then it doesn’t make any sense to use screws AND staples (is there glue too!?).

My problem is the sound is very staticy and I want to see it fixing the speakers is an option.

Any suggestions would be greatly appreciated!

Thanks!

Mudbug, do you also have a CLP-411, or is it a different model? I can check the service manual to hopefully get a clue on opening it up.

That said, I don’t think static in the sound would be a speaker issue - it sounds more electronic. If the speakers are bad, you would get no sound or distorted sound when playing notes. When you say static, I imagine that you are getting static noise when you are NOT playing any notes as well as when you are playing - is that the case? If so, it’s not the speakers - they can’t generate any noise on their own, so something is sending that noise to them.

Yes, I have a CLP 411. Actually, it’s my wife’s and it’s been a while since she’s played it. My wife remembers that while the static was happening, the sound was better through headphones but was getting worse. I also remember that I tried hooking up a little amplifier and that also helped. I don’t remember how I hooked up the amplifier or if we used headphones with it or not. I’m a regular font of information, aren’t I? :slight_smile:

I think in any case I’ll still need to get inside of it. As I said, I got all the screws out but the chipboard was at least stapled under the keyboard. I was considering cutting it somehow but I didn’t know what might be on the other side. Maybe drilling out the staples is the better choice but I would have to be careful not to drill to far, etc.

Any suggestions you can give would be very appreciated!

Here is a bit from the Service Manual on getting inside the CLP-411:

Thanks Sam! That was my problem. I was trying to open the bottom!

I turned it on and after a few moments, a rumbling sound happened so I’m guessing that the problem is with the amplifier. Are there any simple tests and/or repairs I could attempt or should I just consider it a lost cause?

(I got caught trying, as a new user, posting more than three times to a thread - for some reason that’s not allowed. Is there a way around this in case I need to discuss this further?)

Hi mudbug, I promoted you to a basic user so you can post more.

Thanks Cody!

More information:

The rumbling sound doesn’t seem to happen when headphones are plugged in. Several years ago, I set up an external amplifier and speakers fed through a headphone jack. My wife remembers that that seemed to work pretty well but it was clumsy to switch between headphones and speakers. Our nephew said that even the headphones started a up, but fooling around with it today, it didn’t seem to have a problem.

Except for our nephew’s complaint, it seem that the headphone side of things works pretty well.

Any advice or suggestions would be greatly appreciated!

Having something plugged into the headphones jack switches off the speakers, so what I would try next is waiting for it to rumble, and then with headphones on and ready, plug them in at mid-rumble. If you hear the rumble in the phones, then the problem is with the sound generation, and will likely be difficult (= expensive) to diagnose and repair, and require a tech with the ability to do signal tracing of the circuitry. If you don’t ever hear the rumble in the phones (like NEVER), then the problem has to be in the amplifier circuit - which at least isolates it, and possibly makes a circuit board swap the solution.

It sounds like the problem is with the amplifier circuit, then. Is there a way to determine which board needs replacing? Are circuit boards available?

Just wanted to mention that Sam’s very useful comment on 18th October has one error: the DC supplies are not +5, +9 and +8V. On my clavinova the +8V supply measures at about +19V which was a bit alarming at first till I looked at the schematic. For some reason this supply is marked as +B (easily mis-read as +8) and it’s clear from the design that this is a more credible figure.

Jon, good call! That +B is a little perplexing to me also, and I misread it on the schematic for +8.

And as for mudbug’s previous post, the board with the amplifier (PU40D2) is no longer available from Yamaha.

Hi I know this thread is years old now bit Im putting this up incase, as I did, someone comes across it looking to fix there clp-411 with this fault.

My daughter wanting to play the piano to show me what she had learn but was a bit eager and when powering it up and didnt wait for the amp relay to click in, so she rapidly turn it on, off, on, off then on. The relay click and no display LED, no sound, but only the front power light. I had words there but they were all stuck in my throat. My beautiful piano I have had for so long was fried. I found if I slapped it underneath it would power up but had a lot of cackling and noise through the speaker.
My instinct told me it must have arced out the main amp power relay and left it with a poor connection. I work on trucks and we have had the same issue with relays working but have burnt connection which cause the ecu’s to flip out and sluk.
I know this isn’t science and Im not an circuit wizard but I had seen how the fault was made it made sense to me.

So I took a punt and ordered a new relay of ebay. I had to but 5 but they were less then £5 for them all. Today I removed the old one and soldered in the new and the piano works perfectly. It was easy to remove the top just three screws on the back and the amp is in the middle. It now turns on without the slap and has not interference noise. So Im very pleased with myself and wanted to share this. Hope it help someone out there.

Peace to all and dont trust the news

The relay is a:
Omron G5Z-2A
12VDC
CONTACT
5A 40VAC
5A24VDC