Opt Ic Adjustment - Canon A-1 Repair Manual

84
4.1 OPT IC Adjustment
1.
Offset voltage check
1)
Desolder one end of resistor
RTC.
2) Short OPT pin
7 (E)
to
8
(MOS OUT) .
3) Measure the voltage from pin 6 (TP) to ground (Vl).
4)
Measure the voltage from pin
8
(MOS OUT to ground
(V2)
5)
If V2 is within ±0.2 mV of Vl, no adjustment is
necessary .
Pig.
~-2
2. Offset Adjustment
If V2 is not within 0.2 mV of Vl, adjust in the follow-
ing manner .
Fig. 4-3
1) Remove res i stor R NULL
ADJ .
and replace it
temporarily with an approximately 30Rn variable
resistor.
2) Adjust the variable resistor until Vl and V2
are within ±2 mV of each other.