SONY UP-980
Service Manual

5-2. PRINT IS TOO DARK OR TOO LIGHT

START

Is voltage (approx. 5.7 V) at pin 4 of IC6 on MA-91 board output when "CONTRAST"is set as center value?

NO

IC203 and IC201 or peripheral circuit of Q16 on MA-91 board are defective.

YES

Is voltage (approx. 1.4 V) at pin 6 of IC6 on MA-91 board output when "BRIGHT" is set as center value?

NO

Peripheral circuits IC203 and IC201 or Q15 and Q17 on MA-91 board are defective.

YES

Is voltage (approx. 1.5 to 2.5 V) available atpin 78 of IC505 on MA-91 board when head is at the normal temperature? YES

NO

Peripheral circuit IC404 and pins 15 and 16 of CN202 line on MA-91 board, or the thermistor in the head are defective.

Are the required voltages available at each terminal, 3 V at 19 pin of IC6 and IC7 on MA-91 board, and 1 V at 23 pin of the IC's? YES

NO

Peripheral circuit Q21 on MA-91 board is defective.

Is density of stair step printed in test mode properly?

NO

The head voltage or connecetor CN202 line on MA-91 board is defective.

YES

The data buses of IC7 and IC8, data buses of IC602 and IC603, or peripheral circuit IC2 on MA-91 board are defective.

5-2

UP-980(UC) UP-980CE(CE)