So I own a Kawai K4r. I bought it off a guy on the internet from the US back in the early 90’s, this was way before anything like ebay or Gumtree existed and the transaction relied on me having complete faith in the seller and sending him a money order and hoping that he fulfilled his end of the deal and actually sent the thing to me! Well luckily he did and I now have a great synth. But, there has always been problems with it, mainly when using the filter in fast sweeps the sound would get choppy and clicky, I had read that this is due to a software problem but had been unable to find the necessary firmware to do the upgrade. So after some desperation I emailed Kawai in the US;

I am after a firmware upgrade for my Kawai k4 serial number 297547.
I would like OS version 1.4, P207C.  I can do the upgrade myself. Can
you supply the ROM file or advise where I can download it from ?

… and low-and-behold I got a reply. Juan Escobar from Kawai sent me the firmware directly, you legend!  So without further delay I programmed it up.

I already own a decent eprom program so it was just a matter of finding which eproms to use, and since I didn’t really want to mess with classic eproms because they are painfully slow I went on the hunt for a pin compatible replacement for the 27c256 that is used in the K4r. I found that the 27SF512 is a perfect EEPROM replacement, I also changed the battery while had it opened. The rom upgrade has brought this thing to life! it’s like I have a new synth, now I can filter sweep as much as I like and there are no noises! If you need to ROM image just send me a message….

EDIT: I’ve had so many requests for the firwmare that I will now put a link right here:  P207C_K4r  If anyone has any problems with me distributing this LET ME KNOW IMMEDIATELY!!