KN6500 power on and HD-SX3 firmware

Hi everyone

Just got a Kn6500 which has a problem that it wont always boot. ON boot the backlight of the screen lights up, and floppy drive led lights up, but nothing else happens. No leds, and no sound is heard from the keyboard when pressing keys/pushing buttons.

After booting it up for four or five times it started ok. I used the debug menu keys and on the first screen test it says that Table Rom IC13: NG. Everything else says ok. Also pitch bend and modulation dont work, on the debug page, they do not change the parameter values.

I suspect that the ic13 is maybe a little "off" the pcb board, which causes the malfuntion. Sometimes it connects on boot and keyboard starts, sometimes not. Any ideas? or maybe spare parts?

Also bought hd-SX3 board with hd-sx6 harddrive, on which the 6 has been marked with 3. Does that boad need firmware to set up on the kn6500, and if so, where can I get the firmware?