Philips BDL4230E/00 Service Manual page 118

118 BDL4230E LCD
RS232 link fail
Check U28 pin20 is high?
Check U28 pin19 is high?
Check J22 pin RX and TX
is normal ?
Check signal MCU_RX and
MCU_TX is normal
Repair Flow Chart
No
Yes
No
Yes
No
Yes
No
1. Check control pin RS232_TXEN status
(default high)
2. Check R213 or R214 is mouted?
Check control pin RS232_SHDN status (default
high)
1. Check RS232 cable (pin2/pin3 is cross type
or normal type)
2. Cross type must plug in to substratum of J22
3. Normal type must plug in to upper stratum of
J22
1. Check U28 soldering or to change a new
chip
2. Check system RS232 status is setup at off
status