Piano World Home Page Forums Our Most Popular Forums Digital Pianos - Electronic Pianos - Synths & Keyboards KAWAI ES920 need Technical Help !

hi guys I am sad as my KAWAI ES920 is not working

yesterday I click the "on" button as always and the thing didn't turn on. so I pressed repeatedly and sometimes the small blue led lit for a sec. I kept pressing persistently until the unit finally powered on! but all I got is a fixed constant static noise from the speakers and no sound from the keyboard not the headphones. The static noise was the same regardless of me moving the volume slider but it stopped once I shut off the speakers using the switch on the back.

For some reason I decided to spray compressed air on the speakers. I was outside with the keyboard in a sandy/dusty and super hot enviorement for a couple of hours the day beforehand. Turned on the keyboard and it worked like a CHARM! Played it for a few moments, all buttons, keys and sounds worked! thinking I fixed it I went to sleep woke up and that previous problem returned.

Thinking this is not a major problem since it did work for some reason before and after the "problem" I opened up the ES920
and I found this connector having nothing connected to it but I couldn't find any loose wire that would fit (look at the pic with the yellow circle highlight). I have no idea what's the silver chip next to it but it seems important.

If any of you guys know what should I look for or have any experience with the problem I encountered I would really appreciate any help to cure my beloved Kawai out of its sickness

URL link to image of the "lonely" connector

[img]https://ibb.co/c8VZv5W[/img]

thanks to anyone who has advice/insight

If there is no cable loose, this connector must be for manufacturing, service or software development purposes (e.g., access to a JTAG port to attach a programmer or debugger).

EDIT: I just looked picture again and the ID is TP5002 whereas other connetors around has only a "P" prefix, so I will hazard a guess on what that "TP" stands for: Test Point.

oh man... that sucks I have really no idea what causes this problem, I should probably take it to servicing because I can't even diagnose it to know what to do

As you have it open, try disconnecting and reconnecting the connectors, especially those that come from the internal power supply (DCDC converter). Also check the voltage of the AC/DC power brick.

Other than the above working, you may have no choice but taking it to service.

Naive suggestion, but check carefully for dirt in the powwr cord itself (and power socket on the es920). And try a different power cord.

Regardng that empty connector, 99% sure that is not the problem. Many boards have connectors that are used to flash firmware or run diagnostics during assembly or service.

Possibly a power supply issue. Such as a capacitor gone out of specs. Impossible to say. Still under warranty?

Also agree with checking the voltage of the external power supply ..... when connected to a suitable resistive load that can handle the power.

Yeah, checking the power supply is definitely my best bet! I did check the connectors and made sure all are firm but to no avail. I don't have a multimeter though. The inside look very clean actually. I'm going to the store in a couple of hours to check out the board with a different power brick. fingers crossed. if doesn't work I'm going to have to service it, will update

Sounds good chummy. Whatever the cause is ..... this could be a lucky thing if under warranty ...... the bugs will be nicely ironed out.

Did you check with a different power cord? Power supplies problems don't usually come and go. It was not working, then it was, then it was not. I would discard physical problems (cables, sockets, soldering of sockets) before the PSU.

I do not want to be pessimistic onthe warranty.
But since you have opened it by yourself, it might be a clause of ending of the warranty.
However the repair costs might not be that high, so let us know.

what type of dusty environment, what kind of dust, what was the humidity ? and how hot, was it exposed to direct sunlight. spraying the top with compressed air almost certainly didn't do anything. I want to say it's possible that the chassis got hot enough to warp a little, that can in theory loosen connectors, break internal boards but it's unlikely. check the power brick for sure, could've been kicked, overheat possible though unlikely. piano overheating, possible but unlikely. take some more photos when you get the chance later.

Since it has been opened, It would be great to have more pics of the inside of the DP. Just to alleviate my curiosity.....

Nah the warranty was for 2 years and I have it since about Nov/Dec 2020. Just tough luck.
The ES920 has been rock solid. I also handle it very carefully but I could have mishandled it by mistake.
I do take it outside and use it for gigs, etc. I even took it to the lake to film a video clip for my duo's original song with my singer.
day after we filmed and recorded a couple of covers in the garden, it was hot AF and a lot of dust/sand.. However when I opened up the machine I did not find the dust/dirt I was excepting to find.

I went to the place I bought it from and tried a new PSU to no avail. Whatever it is I just sent it to the lab to get fixed.
The ES920 is my work tool and I need it fixed I would do it myself had I had any idea how to diagnose the problem
a qualified tech is better to fix it.

Just from looking at the inside it seems neat and clean. All Wires are color coded and many are held by a nylon restraint so they keep in place and don't create a mess. No major dust, dirt and no visible damage/break anywhere in the components.
I've already gave it to the store to have it fixed so I didn't post any pics. The Kawai ES920 manual says "there are no user serviceable parts inside" and also something in the lines of "don't open the front lid - shock hazard" .. at the beginning I was trying to look for a service manual but couldn't find one. Seems to me Kawai doesn't want users to fix it just send it to techs.
Hopefully it doesn't cost an arm and a leg... and also I hope this is something fixable.

Looks like it was just not getting power to it. The power brick connects to the instrument, and then -- the inside of the instrument will have an internal power supply circuit too, which converts the power brick's higher DC voltage to lower DC voltages that will accommodate for example the digital circuitry etc. They'll likely just be working on that internal power supply (or DC regulator section - to see if any of the components have busted or gone out of specs in that area). Because the instrument was able to start up once ----- the situation sounds quite promising - as in the chances of having it fixed.

Yeah I hope so too. I'm being hopeful since the problem "fixed itself" than reappeared . It's like the board gave me a "grace period" of a few hours of working like a charm so I could finish the 2 tracks I really wanted to finish... if it hadn't done so who knows how long I'd have needed to wait till I got it back and working again

Chummy - know what you mean. Some desktop computers are like that too --- such as when a particular capacitor's capacitance gets out of specs due to aging etc --- which can either lead to intermittent start up issues, and eventually get to a stage where the operation is way out of specs - and no more start up. That's for cases where the rest of the electronics downstream is all good. Sometimes, failed caps can take out other basic components in the power/supply regular area - such as transistors, fuse etc. But a tech has chances of sorting that out if that happens.

It sounds (no pun intended) like some sort of bad contact or solder breakage. Let's hope your service shop sorts this out for you ASAP and at a fair cost.

Watched a YT video a while back where the internal power supply connector on a DP was replaced (old one unsoldered and new one soldered in) due to breakage of the old one. That part gets used a lot, connecting and disconnecting/pushing and pulling. I can see where it could wear out/break and need replacement, although likely rare. Since it powered up intermittently and the new PSU didn't solve the issue, that is a possibility.

Intermittent problems are the worst to try and diagnose.

Either way, good luck with it, and let us know what the problem turns out to be.

Rick

True! Some power supply connectors have been known to develop a crack in the solder, around a metal leg. Very sneaky indeed. And a re-soldering turns the tables from a scare to a wonderful relief.