Kurzweil PC3K8 - won't boot

[readymedia]

Hello here!

My Kurzweil PC3K8 (service manual:https://www.synthxl.com/wp-content/uplo ... manual.pdf) won't boot. After switch on I see following:

* There is a SOUND ROM in BANK1 on Engine Board. BANK0 is empty. The same symptoms are there is both BANKs ara empty.

- all LEDs go on for a second
- then they go off
- then 8 at numpad lights up for a second
- the LCD display is blank
- I can change contrast and brightnes
- no reaction if I press any button
- no possibility to get into a diagnostic mode
- no noise or plopps, at audio out
- the main voltages at J301 are fine: +/-12V and +5V

If I disconnect the POWER_UP_RESET line of the J301 Socket the lcd display shows some pixel chaos... If I touch this line the display wents blank.

Any ideas?

Best!, Ready