User Guide

PAMS
Technical Documentation
RAE-3
8. Troubleshooting
Page 8 – 60
Issue 1 06/01
2.17 COBBA Control Interface troubleshooting
NOTE: If there are problems in COBBA serial interface, self tests fail and there
is ”Contact service” shown on the display. Wintesla shows fails at ”Cobba paral-
lel”.
Check COBBACLK line at J322
Square wave, Freq. 13MHz ?
Signal rising/falling edge 3 to 5 ns?
Check COBBASDA line at J324
Activity?
Check COBBACSX line at J323
Activity?
NO
D300 or PWB
OK?
YES
Check all lines simultaneously, see fig. below
faulty
Signal duty cycle about 50per cent?
Low when inactive?
Signal rising/falling edge 3 to 5 ns?
High when inactive ?
Signal rising/falling edge 3 to 5 ns?
High when inactive ?
Check COBBARSTX a J321
High (about 2.8V) ?
Figure 44.
Figure 45. Write sequence to COBBA.
Figure 45 is a write sequence to COBBA. There should be non–all–zero writes
to COBBA.