The information below applies specifically to the DMR-E100H, but some of it probably applies more generally
to most or all Panasonic HD / DVD Recorder models.  I am indebted to users on
forums.afterdawn.com,
most particularly (link now dead) …
<a href="http://www.dxcc.com/dmr-e85h.htm" title="dxcc.com">Roger Amidon</a>
… for some ofthe information here, which I have combined with my own observations.
| Code | Interpretation where known or guessed | Display | 
|---|---|---|
| 0 1 | F00 | |
| 0 2 | Shows Region Code and other data | REGION 1 MAIN 0650E D TIMER 1000E D DRIVE J 104 ROM M 000 | 
| 1 1 | Intense white picture output test | WHIT I | 
| 1 2 | Intense magenta picture output test | MAG I | 
| 1 3 | Momentarily blanks picture | EE2 I xP 48 | 
| 2 1 | TIMER MUTE | |
| 2 2 | MAIN MUTE | |
| 2 3 | Audio test @ -18dB - L: 1kHz, R: 400Hz | AUDIO 48 | 
| 3 1 | Non-destructive, as far as I can tell, hard disk test (press & hold unit power button to stop) | * s | 
| 4 1 | Shows laser usage in hours for both play/rec | nnn | 
| 4 2 | Shows DVD-RAM drive error code | 0 s | 
| 4 3 | Shows DVD-RAM laser error code | 00 | 
| 4 4 | INFO FFFFFF | |
| 4 5 | PVC R00 1002 | |
| 5 1 | Display/indicator test | |
| 5 2 | PB8 HIGH | |
| 5 3 | PB8 MIDDLE | |
| 5 4 | 00 | |
| 6 1 | Display date of unit manufacture | YYYYMMDD | 
| 6 2 | FI 20 19 147 | |
| 6 3 | Read seek test - power off to stop | |
| 7 1 | PC card adaptor w/r test | |
| 7 2 | Jpegtest | |
| 7 3 | SD card w/r test | |
| 8 1 | Shows AV SCART SVHS Input Settings | AV2_YC - AV1_V | 
| 8 2 | Shows AV SCART SVHS Output Settings | AV2_V - AV1_YC | 
| 8 3 | Shows AV SCART RGB Input Settings | AV2RGB - AV1_V | 
| 8 4 | P50 HIGH OK | |
| 8 5 | P50 Lo OK | |
| 9 1 | Cycle tray open / close until power off held 10 sec | 
To get into the service menu:  In standby with the timer off, press and hold …
     TIME SLIP
     STOP
     OPEN / CLOSE (press last)
… simultaneously for 5 seconds.  Then, on the remote, press the numeric codes shown in the table
To toggle the disk eject from LOCK to UNLOCK:  In standby with the timer
off, press and hold simultaneously for 5 seconds …
     STOP
     POWER
To eject a DVD if the unit won't operate (for example, error U99):  If necessary,
press and hold POWER until the machine switches to standby.  In standby with the
timer off, press and hold simultaneously for 5 seconds …
     STOP
     CHANNEL UP
To initialise all settings to factory defaults:  In standby with the timer off, press and hold
simultaneously for 5 seconds …
     |<<  (Skip Rev)
     TIME SLIP
     OPEN / CLOSE