Table 9-1 Table; Chart 14. 02/90, General Dsp Hardware Failure - Motorola ASTRO XTS 3000 Service Manual

End.
Repair problem
with R410.

Chart 14. 02/90, General DSP Hardware Failure

10-16
Fail 02/90
DSP Hardware
Failure
Verify standard
bias per table
Table 3.
Isolate and
No Standard
repair problem.
bias OK?.
See Chart C.5
Yes
Reflash DSP
code.
Fail Unable to
No No
02/90 Reflash
persists? DSP code?
Yes
Yes
Verify D23 is
pulled high
FLASH
through R410
programming
at power up. error
generated?
Yes
No
D23 is
Use ohmmeter to
high?
electrically verify signal
connections to source
IC as shown in sections
on Fail 02/81 and Fail
Yes
02/88. If failure still
occurs, then refer to
Replace U405.
section on DSP ROM
failure (Fail 02/81).
Chart C.12.
Verify Host Port:
Use ohmmeter to
electrically verify
following signal connections
to source IC:
Signal @ U405
H0-H7
HA0-HA2
HR/W*
HEN*
RESET
HREQ*
On power up, verify
transitions on HEN* from
high to low indicating DSP
is being selected.
Repair opens
as necessary.
No activity
exists on
Host port
No
pins when
operation
measured on
verfied?
U701 at power
up may
indicate a bad
C. If this is
the case
replace U701.
Replace U405.
On power-up the host C sends
several handshake commands
through the host interface to
the DSP system to coordinate
the power up programming of
the ADSIC and detect any DSP
power up status messages..
This error indicates the host
never received a response
from the DSP. The power up
code is downloaded from U404
and executed internally in the
DSP. This is a wide ranging
problem which may be difficult
to isolate without special tools.
Some basic failure modes:
1) Some fundamental system
clocks or supplies are not
operational.
2) Improper operation of the
ADSIC memory mapping
functions.
3) Corrupted DSP FLASH
program code.
4) Hardware problem with host
C/DSP interface.
5) Improper configuration of
MODA and MODB by ADSIC.
6) DSP_RST* not operating
correctly.
7) ADSIC not functional due to
missing 2.4MHz reference.
At power up
No
8) Short or open on DSP
verify state of
address/data bus.
MOD select
pins on DSP
when RESET
goes high:
MODA High
MODB Low.
Verfiy
operation and
No
MOD pins continuity of
RSTx on U406.
correct?
On power up,
Signal should
transition
Yes
from low to
high.
ADSIC RESET
functional?
Source
U701
U701
U701
U701
Verify 2.4
U701
MHz reference
U701
on U406-IDC
per Fig W10.
*Note
frequency may
be off, if
sequence was
aborted before
ABACUS was
programmed.
Reference
Yes
present?
Verify
operation of
ABACUS IC
and repair as
necessary.
Synopsis
No
Replace U701.
Yes
Yes
Replace U406.
No
MAEPF-26028-O