Philips CDR779 - Page 65

Faultfinding Guide
GB 65CDR779 8.
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 :
Motor controller truth table
Figure 8-24
Hall-elements input signal voltage
levels
Figure 8-25
8.3.6 Tray Control
Description
The tray control consists of a TDA7073A power driver (7021)
controlled by the processor 7202 via pin 19 TRAYIN and pin
20 TRAYOUT. If pin 20 is low and pin 19 high, the TRAY+
signal at pin 16 of 7021 is forced to +8V and the TRAY- signal
at pin 13 of 7021 to GND : the tray will open. If pin 20 is high
and pin 19 low, TRAY+ becomes GND and TRAY- becomes
+8V : the tray will close. If pin 19 and 20 of the processor
have the same value, TRAY+ and TRAY- will have the same
value as well : the tray stops moving.
Measurements
Keep procesor 7202 in reset by forcing pin 7 of connector
1208 to +5V. Connect a load of 15Ω, 7W between pin 3 and
4 of connector 1002. Check the voltage over the load with
TRAY+ (pin 3) as positive reference. Check also the levels of
pins 19 and 20 of the processor.
U TRAY+,TRAY- = <100mV
Pin 20 = +5V
Pin 19 = +5V
Force pin 20 of the processor to ground, and check the
voltages.
U TRAY+,TRAY- = -6.5V( 10%
Pin 20 = +0V
Pin 19 = +5V
Force pin 19 of the processor to ground as well and check the
levels again.
U TRAY+,TRAY- = <100mV
Pin 20 = +0V
Pin 19 = +0V
Release pin 20 of the processor and check the levels.
U TRAY+,TRAY- = 6.5V( 10%
Pin 20 = +5V
Pin 19 = +0V
Release pin 19 of the processor and check the levels again:
U TRAY+,TRAY- = <100mV
Pin 20 = +5V
Pin 19 = +5V
Input conditions conn 1006 pin Outputs conn 1006 Test points on driver
684 732 9 10 11 18 17 16
U+ U- V+ V- W+ W- UCOIL VCOIL WCOIL HALL_U HALL_V HALL_W
L M H M M M 6V 0V 0V 0V 5V
H M L M M M 0V 6V 6V 5V 0V
M M L M H M 0V 6V 0V 0V 5V
M M H M L M 6V 0V 6V 5V 0V
H M M M L M 0V 0V 6V 5V 0V
L M M M H M 6V 6V 0V 0V 5V
CL96532086_055.eps
080999
Input voltage Level Tolerance Unit
H2.80.1V
M2.50.1V
L2.20.1V
CL96532086_056.eps
080999