Crown OC-150A - OC-150 Test and Setup Procedures

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* CAUTION: Bewarc oi high voltage points internally exposed while
testing this unit!!
OC-25BA Yest and Sek-Up
Visually inspect the unit for broken wires, cold solder joints
solder bridges and cracked sr braken meters, Clean and check
all switches for proper contact.
With the power on and no input signal:
a) Adjust the meter mechanical FBcenterw "screw Ear. zero
b)
Depress "AC linew and observe panel meters for approx. line
value
Apply a 120 volt input signal to Amp # 1 input (both channelsf
use a true rms peakequivalent AC meter to obtain an accurate Source.
a) Set range to 140~; Switch to VU and depress
amp # 1"
b) Adjust R28 for 120 v on panel meters
Connect a digital volt-meter to the output of IC-2 and ground
a] Set meter switch to "peak" and turn "hold-timeM controls full
clsckwi se
b) Remove signal from the input
c) DVM reading should not vary .001 v over a 30 sec period
dl If signal does vary, adjust R23 or change value of R19,R21
Switch range control-button to 14v, turn "hold-time" controls
to full CCW and feed a 10 volt signal to Amp # 1.
a) Meter should read 3OV
Switch Range control-button to 1,4v, feed in a 1 volt signal.
a) Meter shaufd read 1V
Feed a 7,8V lKHz signal to Amp # 2 input, Take the output from
one of the two fcant panel headphone jacks andbfeed to an A@
vsPmeter,
a) Move headphone attenuator sUde switch to and observe
reading sf L8V (0 db on +20V scale)
b) Move headphone attenuator slide switch to "MIDDLEQ
bAtp
position* Vafkmeter should read = 2,2V (-17db)
C) Move headphone attenuator slide switch to tfMINu position,
Voltmeter shaufd read .6 v Qm22db)