This is the original manufacturers service manual, with detailed info on the circit boards, explosion drawings of all parts in assembly order, and tuning instructions. The only thing missing is the information on the dimensions of the various drive belts. mail me if you need them. gcrossman_at_aol.com
This service manual for the Kenwood KT-990D was reproduced really well ,is very legible and manual is complete.Combined with the low price paid,in the future,I will be checking Owner-Manuals.com any time I need a manual.
Text excerpt from page 124 (click to view)
...from previous page
B
Remove the Main digital board and check the resistance to ground at the Vias points which are the path for the audio signals.
Is the measured resistance below 19 Kohm?
Yes
Repair/Replace the Digital Main board.
No
Repair/Replace the Terminal board.
The next pictures show the location of the Vias in the Main-Digital Board. These Vias are the paths for the audio signals. Check the waveforms and/or the resistance at these Vias. Digital Main Board,