User Guide

PAMS
Technical Documentation
NHD–4
Disassembly & Troubleshooting
Page 21
Original 11/97
1.2 Check CDRFI(N700) pin 63. See Figure 4. Is there a
15.36MHz clock signal present?
– YES! Go to 1.22 / NO! GO to 1.21
Figure 4
1.21 Check this signal solder joints, if OK replace
CDRFI(N600).
1.22 Check connections between ASIC(D704) and MCU
(D706), especially ASIC(D704) pin 104 and MCU(D706) pin
69. If no clock is present and connection looks OK replace
ASIC(D704).
2.0 Are MCU’s supply voltages OK?
Measure MCU(D706) supply voltages from pins 5 and 42 (nominal 3.15V
V
dc
±0.15 V
dc
). Are supply voltages right?
YES! Go to 3.0 / NO! Go to 2.1
2.1 Check PSL_+3V(N500) VL1(3.15V) pin 4
3.0 Is XSYS_RESET signal OK?
Check XSYS_RESET at MCU(D706) pin 10. While a high (about 3.15
V
dc
) is ok, GO to 4.0. If zero then MCU(D706) is in reset, GO to 3.1.
3.1 Is XPWR_RESET signal from PSL_+3V(N500) OK?
– Check XPWR_RESET line from PSL_+3V(N500) pin 8. If it
is high GO to 3.12, if zero GO to 3.11.