Thanks you very much for this "hard to find" service manual.
Will help a lot in repairing this tuner.
Text excerpt from page 6 (click to view)
KMD-671R
ADJUSTMENT
TEST MODE
1. To enter test mode
While holding the �FM� key and preset �6� key, reset the unit. All indication segments are ON at the beginning of test mode.
2. To release test mode
Simply reset the unit. (NOTE) The test mode is not canceled by ACC OFF, power OFF, momentary power down.
3. MD receiver test mode specification
Pressing the �Track Up� key jumps between tracks in the following order. No.7 � No.2 � No.13 � No.23 � No.30 � No.34 � No.7 (Same as the beginning) Pressing the �Track Down� key jumps to the previous track to the being played. Pressing the preset �1� key jumps to No.28 track. Again pressing the preset �1� key jumps to No.22 track.
4. Audio adjustment
The volume is set to -10dB (which is shown as 30). Loudness is OFF. CRSC becomes OFF regardless of the functional excuse, too. The BASS / TREBLE and BALANCE / FADER controls can be set to the full boost / full cut and full front / full rear and full right / full left respectively by pressing the �Track Up� / �Track Down� keys. Sound coordination(Kex / ec4 / dB) doesn't appear for the Audio mode feed.
