Service manual

5-8 Troubleshooting Charts
July 1, 2002 68P81076C25-C
Chart C.7 01/82 or 002, External EEPROM Checksum Failure Chart C.8 01/84, SLIC Initialization Failure
Reprogram
external EEPROM.
External
EEPROM
reprogrammed?
End
Yes
Repair opens.
Connections
good?
No
Yes
Verify operation of
Power-Down Reset Per
Fig. W9.
Reset
Functional?
Replace U407.
No
Yes
Fail 01/82 or 002
External EEPROM
Checksum Failure
Use ohmmeter to electrically
verify following signal
connections to source IC:
Signal @ U201 Source
HD0-HD7 U204
HA0-HA13 U204
HA14OUT U206
EE1CS* U206
OE*,MEMR/W* U206
RESET* U407
VCC +5V
VSS GND
Check for operation of
U204 and U206 as
follows: During radio
power up Self-Test,
verify activity
(transitions from high
to low) on U201 -
EE1CS*, and OE*.
Replace
U201.
No
Yes
No
MAEPF-24415-A
Initial
operation
checks
Good?
Refer to section on
Power-up Failure C.3
and/or Fails to
Bootstrap C.4.
Synopsis
This failure indicates the
External EEPROM data
containing mostly customer
specific channel/mode
information is incorrect.
Basic failure modes are as
follows:
1) The contents of U201 has
been corrupted. A possible
cause of this failure would be
the improper operation of the
RESET circuit during a radio
power down sequence.
2) The decoding logic comprised
of U204 and U206 is not
working properly due possibly
to circuit opens or shorts or
that a failure of one or more of
these ICs has occurred.
3) U201 has failed.
Fail 01/84
SLIC Init Failure
Verify standard
bias per table
Table 3 pertaining
to SLIC.
No
Isolate and
repair problem.
Yes
Standard
bias OK?.
Verify Host/SLIC connections:
Use ohmmeter to electrically
verify following signal
connections to source IC:
Signal @ U206 Source
OE* U204
WE* U204
HD0-HD7 U204
4XECLK U204
HA0-HA4,
HA14_IN, HA15_IN,
HA16,HA17 U204
CSIO1* U204
CSPROG* U204
Synopsis
This failure indicates a failure
in verification of the data in the
SLIC parallel programming
registers Some basic failure
modes:
1) Missing supply or ground to
SLIC.
2) Open in parallel address bus,
data bus or associated select
lines between the host C and
the SLIC.
3) 4xECLK missing to the SLIC.
4) SLIC is faulty.
Verify 4xECLK on SLIC;
nominal 1.8432MHz
square wave, 0-5V.
Connections
good?
Repair
connections.
MAEPF-24664-A
Yes No
Signals
verified?
No
Yes
Replace U206.
Replace U204.