Awesome manual. Complete diagrams of all board assemblies as well as how to get to each part of the t.v. down to the individual screws and their locations. Get it.
This is exactly the service manual I needed.
Complete with all schematics, partslists, PCB layouts and alignment instructions.
This manual covers both the T-4970 en T-488F Onkyo tuner.
Text excerpt from page 2 (click to view)
Technical Manual
IRS Sigma
WIRING DIAGRAM
MIDBASS MID-BASS TRANSDUCER 902-7379 NETWORK A020-7397
YELLOW BROWN BLUE GREEN WHITE
MID/TWT NETWORK A020-7396
HIGH FREQUENCY TRANSDUCER'S 902-5228
GREEN
MID FREQUENCY TRANSDUCER 902-5339A
YELLOW
+
40" BLK 40" RED
BLACK RED RED GRAY ORANGE WHITE
LOW FREQUENCY TRANSDUCER 902-7502
WOOFER NETWORK/BOARD A017-7398
IRS Sigma INPUT ASSY A017-7399
TR1 16" BLUE + Input From Switchboard 16" GREEN MR1 16" WHITE + Input From Switchboard 16" ORANGE 0.91 ohms 5 WATTS MR2 0.91 ohms 5 WATTS 6.8 ohms 5 WATTS TR2 6.8 ohms 5 WATTS