Crown Com-Tech 1610, Руководство по обслуживанию

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Com-Tech 810 and 1610 Amplifier Service Manual
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6-1
Rev. 0
6.1 General Information
The following test procedures are to be used to verify
operation of this amplifier. DO NOT connect a load or
inject a signal unless directed to do so by the proce-
dure. These tests, though meant for verification and
alignment of the amplifier, may also be very helpful in
troubleshooting. For best results, tests should be per-
formed in order.
All tests assume that AC power is from a regulated
source. Test equipment includes an oscilloscope, a
DMM, a signal generator, loads, and I.M.D. and T.H.D.
noise test equipment.
6.2 Test Procedures
6.2.1 Standard Initial Conditions
Level controls fully clockwise.
Stereo/Mono switch in Stereo.
Sensitivity switch in 26 dB fixed gain position.
70-V mode switches in the 8/4 ohm position.
Place a jumper across pins 3 and 4 of both TP100 and
TP200. This will keep the amplifier out of auto standby.
It is assumed, in each step, that conditions of the am-
plifier are per these initial conditions unless otherwise
specified.
6.2.2 Turn On Delay
Spec: 4 seconds ±2 seconds.
Procedure: Up to 1 second after turn-on, the current
path to the primary is through an NTC. After 1 second
a relay closes that shorts out the NTC. Three seconds
later bias is applied to the output section of the ampli-
fier.
6.2.3 Output Bias Adjustment
Spec: 320 to 340 mVDC.
Procedure: While the heatsink temperature is less than
40° C measure the DC voltage on the output module
across R37 (15 ohm), adjust R02 if necessary. Mea-
sure the DC voltage on the output module across R39
(15 ohm), adjust R33 if necessary. Repeat for the sec-
ond channel.
6.2.4 ODEP Voltage Adjustment
Spec: See chart
Procedure: Measure the heatsink temperature. If un-
able to do so, note the room temperature and do this
procedure while the heatsink temperature is still at room
temperature.
Measure the voltage on TP100-5 and adjust R186 for
the voltage per the chart. This voltage will be a nega-
tive voltage. Measure the voltage on TP100-10 and
adjust R300 for the voltage per the chart. This voltage
will be a positive voltage. For channel 2 the designa-
tions are TP200-5, TP200-10, R286, and R400.
ODEP Voltage Chart
Tolerance ±0.1V
°F °C Voltage
66 18.9 10.55
68 20.0 10.48
70 21.1 10.41
72 22.2 10.34
74 23.3 10.26
76 24.4 10.19
78 25.6 10.12
80 26.7 10.05
82 27.8 9.97
84 28.9 9.90
86 30.0 9.83
88 31.1 9.75
90 32.2 9.68
92 33.3 9.61
94 34.4 9.54
6.2.5 DC Offset
Spec: 0 VDC, ±10 mV.
Procedure: Measure DC voltage at the output con-
nectors (rear panel). There is no adjustment for output
offset. If spec is not met, there is an electrical mal-
function. Slightly out of spec measurement is usually
due to U104/U204 out of tolorance.
6 Electrical Checkout
Procedures