Philips DVD712 Service Manual page 31

Diagnostic Software Descriptions And Troubleshooting
5.8.4 Reset
Check next reset timing with an oscilloscope at pin 10 of the
microprocessor.
PM3392A
ch2
ch1
T
2
1
CH1 2.00 V=
CH2 2 V= BWL MTB 100ms- 1.04dv ch2+
Figure 5-42
Timing: 400msec < T1 > 700msec.
CH1: +5Vstby voltage at power on.
CH2: Voltage at pin 10.
5.8.5 Display Steering
Check next timing and level for all grid-lines (G1 r G14).
PM3392A
ch1: low =-34.2 V
ch1
ch1: high= 3.98 V
1
T
CH1 10.0 V=
Figure 5-43
1. Check level A: +4V5 +/-10% for grid lines 1 => 11
2. Check level A: +4V0 +/-10% for grid lines 12 => 14
3. Check level B: -33V +/-10%
4. Check timing and levels of segment-lines P1 => P10:
PM3392A
ch1
1
T
CH1 10.0 V= BWL MTB 500us- 1.04dv ch1+
Figure 5-44
Level A:+4V5 +/-10%
Level B:-33V +/-10%
The data on these segment lines depend on the characters
that are displayed.
The characters can be set by sending I2C commands to the
display.
T1
CL 96532065_073.eps
130799
A
B
STOP
MTB 200us 2324us ch1+
CL 96532065_074.eps
130799
A
B
CL 96532065_075.eps
130799
DVD712-722
See the Slave URS how to send a display command.
5.8.6 Key-Matrix
Connect a extra 10k W pull-up to pin 36 en 37 of the m P and
check next matrix scanning at these pins.
PM3392A
ch1: low =-46.9mV
ch1
ch1: high= 5.09 V
B
1
CH1 2.00 V= MTB10.0ms
Figure 5-45
Level A: 5.0V +/-7%
Level B: 0V +/-200mV
Check matrix scanning from pin 26 until 33 of the m P.
The results should be the same as the diagram above.
5.8.7 I.R. Receiver
Check at pin 23 of the m P if this line switches from low (<
0.3V) to high (> 4.5V), while pressing a key on a Philips RC5
or RC6 remote control.
5.8.8 Karaoke Interface
The karaoke interface (4 lines) is a single direction
communication.
This means that it consists of four m P output lines.
The interface can be checked by setting or resetting these
output-ports via the I2C bus.
Send next command via the I2C bus:
Address
Command byte
Data byte
Where
5.8.9 P50 Interface
P50 is a bi-directional serial interface, which is used for
communication between video equipment. For European
sets, this communication goes via pin 10 of the scart-bus. In
other regions, it can be a cinch bus at the back of the set.
1. Keep the m P in reset by short-circuiting emitter and
collector of transistor 7108, via resistor 3100 and 3104
transistor 7101 is switched on.
2. Check the voltage at the P50 output connector 1118-5: <
200mV.
When the reset is released the m P output-pin becomes low
and transistor 7101 is switched off.
1. Check the voltage at the P50 output connector 1118-5:
4V9 +/-5%.
2. Check also the m P P50 input ( m P pin 20): 5V +/-5%.
3. Connect the P50 line (connector 1118-5) to ground.
4. Check again the m P P50 input ( m P pin 20): <0V3.
5. GB 31
A
STOP
ch1-
CL 96532065_076.eps
130799
: 0x70
: 0x24
: xxxxabcd
: a = Karaoke reset.
: b = Karaoke data.
: c = Karaoke clock.
: d = Karaoke strobe.