Yamaha CS-30 Service Manual page 39

CS-30(S/# 1001-)
PRA Circuit Board
1. Amplifier Circuit
Set the PN3 VOLUME to MAX and make sure that an input signal of about 0.3V is applied to terminals
II
(CO
—7) and 21 (1)—9) respectively when the key is turned ON. Then, adjust [VR l] and [VR2] so
that 0.6V signal appears at terminals 1H (J —5) and 2H ( £—13) respectively.
At this stage, lOOmV output must be obtained from terminals 1L (Y-2) and 2L (;£—11) respectively,
and also 0.6V output from 1 + 2H ((2 —2) and 50mV output from 1 + 2L (CD-IS) terminals.
2. Headphone Amplifier Circuit
When a set of headphones (8 ohm) is connected to the PHONES jack on PN3, 250mV output should be
obtained from terminals HR ((2)—13) and HL
{%—
12).
3. Initial Clear Circuit
Connect either a set of headpnones or a guitar amplifier, turn the key ON and make sure that a sound is
produced. Turn the main switch OFF and then turn it ON after 10 seconds. A sound should be heard
about 8 seconds after the main switch has been turned ON.
4. Foot Controller Current Regulation Circuit
A +14 ± IV and —14 ± IV should be obtained from terminals +X ( 2 —15) and —X ('2,-14) respectively.
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