User Guide

PAMS
Technical Documentation
RAE-3
8. Troubleshooting
Page 8 – 41
Issue 1 06/01
2.10 Serial Interface Troubleshooting
2. Check and replace
1. Check Serial connector
4. Check DCE_Rx (AccTxData)
3. Check DCE_Tx (AccRxData)
Serial I/O
OK
NO
Serial Interface problem
Flashing
successful?
X450 spring contacts
ESD protection device V451
comp. R452, C458, R300
comp. R450, C453, R309
Flashing
successful?
Check that ”DTR Detection”
state changes by pressing
ACC_VOLTAGE switch
in the service jig
Activate WinTesla,
observe
ADC–readings
OK?
Check DCE_DTR line
comp. R454, C459,V489, R310
OK?
Refer to Accessory power
output troubleshooting
Faulty MAD (N300)
or PWB fault
OK
YES NO
YES NO
NO
YES
5. Check DCE_DCD (MBus)
comp. R453, C457, R307
Figure 30.
NOTE1: Ensure that the customer’s DLR–2L is OK.
NOTE2: Wintesla ADC–readings for ’DTR Detection’: state ”0” = DCE_DTR
– line at 2.8 – 3.0V
Wintesla ADC–readings for ’DTR Detection’: state ”1” = DCE_DTR
– line at 0 – 0.3V
NOTE3: Signal levels in practice: High  2.7V, Low  0.3V
Exception: Diode in DTR line causes voltage drop, see Figure 31 below: