KR-4500 Schematics

[Ngrai]

Hello Beaver,

I finally got the KR4500 here for repair. ... Anton, if you are reading this: could you send me a copy of the schematics - might be handy to have in case of trouble.

All the best
Uncle Victor
luc@e2t.eu

I hope you are still reading posts to this forum -- your expertise remains invaluable as KR-4500s continue to deteriorate and non-experts like me need help. The KR-4500 was an expensive piano. We bought ours new more than a decade ago, and it was faultless until we shipped it to our new home in Hawaii two months ago. Maybe the sea air on the cargo ship, and here on the island, has accelerated the electronics decay.

Anyway, we're now having the problems everyone else has been having in this forum -- crackling through the speakers, odd messages in the little window, a urine smell (our first thought was that a rat had gotten inside the keyboard on board the ship!)

If I use the piano purely as an amplifier for my iPad (connected through the line-in jacks at the back of the piano), where the iPad controls volume, then there is no crackling. It's only when I turn up the piano volume control that the crackling -- and the smell, from near the volume slider -- occurs. So I guess I might be lucky and just have a bad volume control or component.

Anyway, I'm sure I can find a local electronics whiz to fix it, but I imagine he will need the schematics, as you did. If you received them and still have them, would you be kind enough to share?

Or anyone else reading this, who has the schematics -- any and all help appreciated, thanks.

[huladaddy]

Bump...

Does anyone have any spare parts for this piano? Spare motherboard? :)

[alex_2012]

hi to all. today i buy slightly damaged KR4500. It has noisy(crackling) sound and slightly vibrated sound if play piano. I am prepared to change capacitors and I would like to ask someone who has a scheme for sending it to me. Thank You in advance. My email is: alesandro(rollmop)seznam.cz
I will write later what happened after repair
BR
Alex

[alex_2012]

ok service manual i get directly from Daniel Burton.
Thank You Again to Dan
and I wish nice day to all :)

[alex_2012]

so my piano is working again? :) all caps are changed by tantalum caps. By scheme are all caps used as power filtering and tantalum caps are most useful for this. Before repair was very noisy right channel and it was changed by volume slider. now it is absolutely clean if i don't play and volume is on max for example. but little bit problem is by playing piano has right channel still little electronic echo? PCB was very damaged from leaked old caps. It isn't visible at first look. after desoldering caps is damaged PCB below or vias around. Fortunately there are lot of multiple vias to ground to bottom layer. So my last fight is signal from BurrBrown device to operation amplifier and device about. My question: someone tried change standrard floppy drive by "fdd to USB convertor" ?? for example this: http://www.ebay.com/itm/New-Upgrade-3-F ... 3cbea5e3a8
Someone tels me that is function on Roland W30 and it uses the same file structure...

[hape9012]

Hi all,
I got a KR4500 recently which definitly also requires some "service".
Some keys (10) give no resonse at all others (2) respond not at a correct sound level.
Furher it seems to have a problem with the start-up so initially the sound is OK then it is muted for about 3 sec
before it comes back. Finally some of the setting buttons are broken or do not respond.
So there is definitely some work involved in bringing back as much function as possible but I don't want to give up yet.
The most helpful information at the moment would be some instructions on how the keys
can be disassembled and definitely a schematic, circuit diagram or some service documentation would be helpfull.
Is there anybody who could help me with some of these issues ?

Regards,
and Thanks for any help
HaPe

[hape9012]

Hello all,

I figured out how to get the keys out so that problem is solved.
However I havent' found yet the root cause why they do not work
so any schematic might still be helpfull.

HaPe

[hape9012]

Hi,

Thanks for the support Alex ... so now the challenge can start.
Hopefully I don't break more than I fix.

Thanks again,
Hape

[KR-4500-Fan]

This thread is years old but anyway, I have a copy of the schematics for the KR-5500 (identical to the KR-4500). Forum users can send me a private message if assistance is needed.

[oldrectorycottage]

Hi,

I have just aquired a roland kr-4500.

All seems to be ok except for the following

• Occasionally a note will repeat itself much louder one on key press
  Some of the higher/lower keys play the note correctly, but when they have decayed there is a littel residual high pitched sound.
  One of the function keys ('Layer') has been pushed down a bit so is not in place and does not work.
  There was mention of the USB drive replacing the floppy with an item from ebay - can this be done?

Many thanks

[KR-4500-Fan]

Congrats for this wonderfull ePiano, oldie but goldie!

> Occasionally a note will repeat itself much louder one on key press
Most likely the contacts of the key are defect, self-reapair difficult or impossible, I would replace the octave with defect key, hopefully available as replacement part, ask manufacturer.
> Some of the higher/lower keys play the note correctly, but when they have decayed there is a littel residual high pitched sound.
Sounds like a defect capacitor... might be difficult to find, if there are no obvious electrolytic leakage on circuit board.
> One of the function keys ('Layer') has been pushed down a bit so is not in place and does not work.
apple juice in the mechanics? Usually can be easliy fixed by opening the case and cleaning the mechanics of the button.
> There was mention of the USB drive replacing the floppy with an item from ebay - can this be done?
Sounds like technically possible, but I have never tried.

[Projectroland]

Hi...I also have a "project" KR-4500....does anyone know the circuit board responsible for the "smell " and crackley sound ? Power ? Audio ? or any good ideas ...
Thanks
Bob

[meeshow44]

i have dead keys, its every two notes... so C#D# in the first octave, third, fifth, seventh, ABFG in the second, 4th, 6th, 8th,...but every other key works fine, there's a pattern

i've changed the pads, and the flat wire that goes from the keys to the processor...any ideas?

[huhu]

Hi,

I have to fix a KR-4500. I changed all the caps, but one of them was like really blown up and damaged the conducting tracks on both sides of the board. Now I want to recreate the missing parts of the track and am looking for the schematics. It would be kind if someone could send me the schematics or where to get it.

Cheers Chris

[YvanJal]

Hi !
I also have to fix my KR-4500 motherboard. I replaced a lot of damaged surface mount caps but I'm afraid I accidentally induced a problem with the "Pitch Bend" that doesn't work anymore. If I could have the schematics or a photocopy of the pitch bend circuit from the pot to the connector on the main board and from that connector to the next circuit on the board, it would be very appreciated. I know for instance that the pot goes to pin #4 on the motherboard connector but I can't follow it on the board.
Thanks
YvanJal