Yamaha DVD-S510, Service Manual, Page: 20 / 78

DVD-S510/DV-S5350
19
1.5 Key-matrix
Connect a extra 10kpull-up resistor to pin 36 en 37 of the
µ
P and check next matrix scanning at these pins.
PM3392A
ch1
ch1: low =-46.9mV
ch1: high= 5.09 V
STOP
CH1 2.00 V= MTB10.0ms ch1-
1
B
A
Figure 5
Level A: 5.0V +/-7%
Level B: 0V +/-200mV
Check matrix scanning from pin 26 until 33 of the
µ
P.
The results should be the same as the diagram above.
1.6 I.R. receiver
Check at pin 23 of the
µ
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.
1.7 Karaoke interface
The karaoke interface (4 lines) is a single direction
communication.
This means that it consists of four
µ
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
: 0x70
Command byte : 0x24
Data byte : xxxxabcd
Where : a = Karaoke reset.
: b = Karaoke data.
: c = Karaoke clock.
: d = Karaoke strobe.
1.8 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
µ
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
µ
P output-pin becomes low
and transistor 7101 is switched off.
1. Check the voltage at the P50 output connector 1118-5:
4.9V +/-5%.
2. Check also the
µ
P P50 input (
µ
P pin 20): 5V +/-5%.
3. Connect the P50 line (connector 1118-5) to ground.
4. Check again the
µ
P P50 input (
µ
P pin 20): <0.3V.