Motorola ASTRO Digital Spectra Plus Detailed Service Manual page 227

Troubleshooting Charts
Fail 01/88
Host C External RAM
Failure.
Verify standard
bias per table
Table 3 pertaining
to host C.
No Standard
Isolate and
bias OK?.
repair problem.
Yes
Verify Host RAM:
Use ohmmeter to
electrically verify
following signal connections
to source IC:
Signal @ U202 Source Signal @ U206
HA0-HA13 U206
OE*
HD0-HD7 U204
WE*
MEMR/W* U206 HD0-HD7
OE* U206 4XECLK
CS* U211
HA0-HA4,
HA14_IN, HA15_IN,
Signal @ U211 Source HA16,HA17
IN_B U204 CSIO1*
IN_A U206
CSPROG*
During radio power up
Self-Test, verify
Yes
activity (transitions
from high to low) on
U202 OE* and WE*.
During radio power up
Self-Test, verify
No
Signals
Yes
Replace U206.
activity (transitions
verified?
from high to low) on
U202 CS*.
Verify operation of
U204 and U211 logic AND
No Signals
gate. During radio power
verified?
up Self-Test, verify
activity (transitions
from high to low) on
U211 IN_B.
No Signals Yes
Replace U204. Replace U211.
verified?
MAEPF-24665-B
Chart C.9 01/88, MCU (Host mC) External SRAM Failure
6881076C25-E
Synopsis
This failure indicates a failure
in the C external SRAM at
power up test. 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 and the SRAM.
3) 4xECLK missing to the SLIC.
4) SLIC is faulty.
5) Improper decoding logic due
to open or failure of U211 AND
logic gate.
6) SRAM is faulty.
Source
U204
U204
U204
U204
U204
U204
U204
Connections No Repair
good? connections.
Yes
Replace U202.
Fail 01/92
Internal EEPROM
Checksum Failure
Verify operation of
Power Down Reset Per
Fig. W9.
Reset No
Functional?
Yes
Reprogram Internal
EEPROM.
Internal
No
EEPROM
Replace U204.
reprogrammed?
Yes
Realign radio.
End
MAEPF-24407-B
Chart C.10 01/92, Internal EEPROM Checksum Failure
5-9
Replace U407.
Synopsis
This failure indicates the Host
C internal EEPROM is incorrect.
This data contains, among other
things, radio tuning parameters.
Basic failure modes are as
follows:
1) The contents of the internal
EEPROM have been corrupted.
A possible cause of corrupted
data may be improper operation
of the power down RESET
circuit U407.
2) An internal failure of U204
has occurred.
September 5, 2008