Good day all..:)
sorry for my bad english

introduces me self im from indonesian and i am a new keyboard technician, need help about my job.

I have a two pcs of keyboard technics KN 1400 errors, the both of them have the same type of error.
If the device switch on normally the device will on but just error text shown in display: CAUTION "ERROR IN CPU DATA TRANSMISSION", no panel lamp is on and nothing respon any tab or key. But when the device switch on while holding the key/chord (B+F) the display will shown like this device will on normally but until logo KN 1400 and EQ preset, ater that will not responding any key or tab,no panel led is on.

I hve open the device and i don't meet any damage or something wrong (like burning component or other damage).
And i have try to change each other pcb parts with other part, but still same error shown.

The owner says that error after style songs copy procces via floppy disk.
If any experience about this case, please help me and any help would be greatly appreciated. Thank's before

Best regards:

Kahar Kelana