Panasonic DMR-XS350EB Service Manual page 12

Main functions
1. Execute Tuner Service Mode
Turn the power on to receive digital broadcasting (HD broadcasting).
Press and hold [POWER] (Unit Key) and press [OPEN/CLOSE] + [REC] for 5 seconds at the same time.
2. Finishing Service Mode
Method 1: After turning the unit "OFF", pull out the AC cord.
Method 2: Repeat turning ON and OFF twice: P-OFF → P-ON → P-OFF → P-ON.
3.6.1. Hard Test (Device Test)
Perform Access Test for each hard device and display the result.
12