Ba6856Fp Turn Table Motor Driver (7020); Tda7073A Power Drivers (7021, 7022) - Philips CDR775 Service Manual

GB 60 8.
Pin Configuration
HFREF 1
HFIN 2
ISLICE 3
V 4
SSA1
V 5
DDA1
I 6
ref
V 7
RIN
D1 8
D2 9
D3 10
D4 11
R1 12
R2 13
V 14
SSA2
CROUT 15
CRIN 16
Figure 8-23
8.3.4

TDA7073A Power Drivers (7021, 7022)

Description
The TDA7073A is a dual power driver circuit for servo systems
with a single supply. In this configuration it is used to drive the
sledge, tray, focus and radial.
Measurements
Keep microprocessor 7202 in reset by forcing pin 7 of
connector 1208 to +5V. Connect the power supply as
described above in "1.1.1. Supply Voltages". Check the
following voltages :
Pin Location
5 7021
5 7022
1 7022
2 7022
6 7022
7 7022
1 7021
2 7021
6 7021
7 7021
Figure 8-24
CDR775 Faultfinding Guide
48
47
46
45
44
43
42
41
SAA7324
40
39
38
37
36
35
34
33
CL96532086_052.eps
Value
12V ± 10%
12V ± 10%
1.65V ± 10%
1.65V ± 10%
1.65V ± 10%
1.65V ± 10%
5.0 ± 10%
5.0 ± 10%
1.65V ± 10%
1.65V ± 10%
CL96532086_053.eps
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Pin
9
12
SBSY
13
SFSY
16
9
SUB
12
RCK
13
TEST3
16
STATUS
SILD
RAB
SCL
SDA
RESET
8.3.5

BA6856FP Turn Table Motor Driver (7020)

SCLI
SDI
Description
WCLI
This component is a 3 phase, full wave pseudo linear driving
V2/V3
system with inbuilt Hall Bias circuit and 3 phase parallel output.
V
SSD1
Measurements
Keep processor 7202 in reset by forcing pin 7 of connector
1208 to +5V. The outputs 9, 10, 11 of connector 1006 are 0V.
Pin 21 of the motor driver 7020 is 2.5V ( 10%.
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Pin 22 of the motor driver 7020 is 2.5V ( 10%.
Pin 23 of the motor driver 7020 is 0V.
Pin 19 of the motor driver 7020 is 5V ( 10%.
Put the processor out of reset to continue the measurement.
Check MOT1 at pin 59 of CD10. The duty cycle of the output
should be 50%. Check wave form at pin 11 of 7005-D :
amplitude 5V + 5% duty cycle 50%.
The motor driver 7020 can be measured dynamically by
connecting a hall motor to the application panel. Apply a pulse
of 1V 10Hz and 15% duty cycle to pin 22 (Ec) as input value
with reference to pin 21 (Ecr=2.5V). Measure the output signals
on the driver. This will give as response a square wave on pin
17 and pin 18. When a positive voltage is applied, the square
wave on pin 17 will go ahead of the square wave on pin 18.
All signals will have a value as shown in the truth table. Check
the following output signals :
Location Value DC
5.8V ± 10%
7022 FOC
7022 FOC 5.8V
7022 RAD 5.8V
7022 RAD 5.8V
7021 SLE 5.8V
7021 SLE 5.8V
7021 TRAY- 5.8V
7021 TRAY+ 5.8V
CL96532086_054.eps
Figure 8-25
080999