TB 9-6625-1976-35
9. Distortion
a. Performance Check
(1) Connect TI OUTPUT to audio analyzer HIGH and LOW INPUT terminals
using a balanced cable.
(2) Press audio analyzer FLOAT key (assure illumination).
(3) Set FREQUENCY RANGE-Hz switch to 100 kHz and FREQUENCY dials to
50.00 K.
(4) Set VOLTAGE RANGE switch to 100 V and VOLTAGE dials to 10.0000 V.
(5) Set SENSE switch to INT and MODE switch to OPER.
(6) Measure distortion. If distortion is not less than 0.041 percent, perform b below.
(7) Adjust resistance standard to 200 Ω and connect across TI output.
(8) Measure distortion. If distortion is not less than 0.07 percent, perform b below.
(9) Repeat technique of (1) through (8) above for settings and indications listed in
Table 4. Distortion
Test instrument
Audio analyzer indications
VOLTAGE
VOLTAGE
RANGE-HZ
RANGE
dials
dials
standard
No load
With load
switch settings
switch settings
(V)
(Hz)
settings
(%)
(%)
(V)
(Ω)
100
20.0
1
1.000000
---
<0.081
---
100
K
20
K
1
1.000000
20
<0.041
<0.1
100
K
50.00 K
1
1.000000
20
<0.041
<0.19
100
K
20
K
10
10.00000
200
<0.041
<0.046
100
K
50.00 K
10
10.00000
200
<0.041
<0.055
100
K
20
K
100
100.0000
---
<0.041
---
b. Adjustments
CAUTION
In the following check, TP4 and TP5 are floating at
approximately + 190 V dc above chassis ground. Isolate the
multimeter from chassis ground and use appropriate
precautions.
(1) Connect multimeter between A7TP4 (LO) and A7TP5 (HI) (fig. 1) of the power
amplifier board.
CHANGE 1
