The service manuel is very helpful, we where able to restore the device to its working operation again.
Text excerpt from page 29 (click to view)
DV-SP504 TEST MODE/ CONFIRM FW
1. Confirm Region code 1-1. Press "Dimmer" key and "Pause" key at the same time. 1-2. Press "Pause" key. Display "Region Code " on the FL tube.
MDD1N : USA 1 NTSC MJJ2N : JPN 2 NTSC MUK3N : ASIA 3 NTSC MUP2P : EURO 2 PAL MUT3P : ASIA 3 PAL MUA4P : AUS 4 PAL
2. Test Mode 2-1. Press "Stop" key and "Display" key at the same time with NO DISC condition. 2-2. Display "SYS 06830A" on the FL tube.
(Version number of System MICIN)
2-3. Press "Display" key three (3) times. 2-3. Display "0E-060907A" on the FL tube.
(Version number of Back end MICIN) TV MONITOR Release Version : OE 060702A (HP-1-------) FE BE Version : 10.26 Version : 1508530000 H: Writing of HDCP key OK P: Writing of CPPM key OK 1: Region number
2-4. Press "Display" key two (2) times. Light up all segment of FL tube. 2-5. Press "Standby" bottom to exit the test mode. 3. Initializing 3-1. Press "Stop" key and "Standby" key at same time with No DISC condition. Display "INITIALIZE" on the FL tube. 3-2. And display "COMPLETE" to "STANDBY".
