Disklavier

I own a Disklavier DC2A with the DKC55RCD control unit.   The piano is almost 
3 years old.  Last week the piano went entirely dead while it was playing.  I 
removed the CD/Floppy control unit from the piano and took it to the local 
Yamaha dealer.  I hooked up the unit to a known working piano and it worked just 
fine.  I believe that isolates my problem to the amplifier itself.  Yesterday 
the technician (a piano tuner by trade) came to my home.  After laying under 
the piano for a few minutes with a $30 Radio Shack VOM, he surfaced and said 
that the power supply was bad. I offered my phone and my FedEx overnight 
priority account number to enable him to get some parts coming.  He declined.  He 
wasn't sure if Yamaha was going to send an entire amp or just a circuit board.  
I encouraged him to call to find out.  He advised that he didn't have enough 
information to make a call.  He needed other information that he did not have 
with him.  That irritated me as I had given him the above mentioned explicit 
information at the time I set up the service call.  I had checked all of the 
connections as he had directed over the phone... to avoid a nuisance service call 
for some easy to fix reason.  Here are more specific symptoms that the piano 
exhibits:  When the on-off button is depressed, absolutely no lights 
illuminate or disk operation occurs.  A tiny relay does click in and out within the amp 
itself when the on/off switch is depressed.
 
Yes, it's probably a power supply or related circuitry.
 
Does Yamaha typically replace boards or do they swap the entire amplifier 
unit?  Do they have an exchange program or does the suspected item have to be 
returned to Yamaha for repair?  What is the tech support number at Yamaha?
 
I'm a former TV repair technician, yet I purposely left the piano repair up 
to a "qualified" technician as it is still under warranty... but if this is a 
simple board or amp swap, I'll gladly do it myself.  By his own admission, the 
repair person is not at all familiar with the removal/repair of the amplifier 
unit.
 
I'd appreciate any help from this group.  I believe that an infusion of 
additional knowledge will enable me to move this repair ahead to a successful 
conclusion.
 
Thanks.....Merry Christmas

I've checked all of the fuses...all 4.  None of the fuses are open.

Thanks for the tips, Carol.  

The outlet is a 3 prong.  Wired to code with a dedicated ground circuit in 
addition to the hot and neutral legs.  119.7 volts measured with a DVM.  The 
piano has played flawlessly for 2 years and simply quit in the middle of a song.  
Totally dead.

Roma from tech support advised that the only things I should (could) check 
were the 4 fuses.   All fuses have continuity.  Ironically, she never mentioned 
any other possible scenarios that could shut down the system.  Yes, you are 
right... virtually always, a blown fuse is for a reason... not just a blown fuse 
for fuse sake.  

I tried in vain to give her what I believe is a very telling bit of 
information.  Over the last several months on rare occasion the piano would not shut 
off.  When the off button was depressed on the control head, the main relay 
would not disengage.  The led screen would stay lit as well.  Unplugging the cord 
would be the only way to shut off the piano.  When unplugging the cord, then 
the relay would disengage.  Often, the piano would then turn off and on 
correctly for several weeks thereafter.  I am guessing that this relay has now stuck 
in the open position altogether.  Roma was unwilling to get into that subject. 
 Is the relay an integral part of the power supply circuit board?  Is the 
relay externally mounted on the chassis?  Is the relay technician changeable?  
Or, does Yamaha always change "the entire black box"  and worry about technical 
troubleshooting back on the bench at Yamaha?  Those are questions that went 
unanswered yesterday.  I offered to lay on my back with my DVM under the piano 
and read Yamaha any test point voltages that they wanted.  I had a fax machine 
and the net at my disposal to facilitate the exchange of information.  Roma 
declined to use any of these tools.  

At the moment, I am anxiously waiting for FedEx.  Roma kind of promised... 
yes, kind of promised that she would overnight FedEx a new "power supply" as 
they call it.  She said "the whole black box"... to which I responded, then 
you're sending me not only the power supply, but also the amplifier, tone 
generator, etc. to which she replied, no... only the power supply.  So I said, then 
you're just sending me the power supply circuit board... No, she said,  the whole 
black box.  That tells me that this person at tech support does not have a 
technical background at all, as she believes that the only thing the black box 
does is act as a power supply (smile).  It took a while to get Roma comfortable 
with the fact that I could perform this repair myself.  I mentioned that in a 
previous life I had built over 30 Heathkits including TV's and AM-FM 
Receivers with literally hundreds of hand soldered parts.  I believe I had finally 
made Roma comfortable that I would not blow up the piano LOL.

The piano tech from my local dealer just called as I am typing this.  Looks 
like he may have messed up my deal with Yamaha.  He advises that they want him 
to do more testing before sending parts.  He advised that Yamaha is now closed 
until Jan 2nd... ok, I'm getting steamed now.  He couldn't even tell me what 
testing, however... hmmm.  It's 11:30 am Milwaukee time and I'm beginning to 
believe that the overnight FedEx shipment is not going to happen.  I just 
called my local dealer back.  They're very embarrassed and offering to give me the 
infamous black box from a DC1 on the showroom floor.  I'm going to remove mine 
and make the swap.  Thanks for your help everybody and stay tuned.   Jim