Motorola StarTAC130, Service Manual

Page: 34 / 84

Page 5
- MOTOROLA CONFIDENTIAL PROPRIETARY -
GSM Krunch - Level 3 Procedure vers.1.1
03/05/1999
See diagrams on GSM
Startac/COSMO Lev.4 procedure
No PWR UP
START
Set the voltage of power supply 5V
Supply the PCB via ext.conn J600
Check the PCB ext.conn.J600 socket CR903 and NOTE 1
Is 4.73V
voltage DC
present at
U900
GCAP pin
40
Supplement 3
PCB only
No pwr up
Does the
PCB draw a
lot of current
and also
does the
alert buzz?
Is L275 short
to ground(Use
an "Ohm"
meter to
measuare the
terminal of
C902 or 903)
Pull up the w.dog by shorting the pads TP10 - TP1
Use a power
supply (2.75V,
150mA).
Supply C902 at
terminals and
check the hot
component.
It's likely to micro
DCA or
C751-753-754-755
(0.047uF)
yes
yes
no
no
Try to connect the PCB to emmibox if the
PCB reblow the appropiate SW from it
(see the led status only)
no
Check U900 GCAP and
NOTE 1
yes
3
no
Are U900 GCAP voltage ok(use Osc.scope)?
Attention at the tantalio capacitor(orange) polarity.
1)
Vswitch at C915= 5.6V (NO RIPPLE, it cause the alert
buzz if it's present replace C915)
2)
R475 at C906= 4.75V
3) L500 at C901= 5V
4)
Vref
at C803= 2.75V( it isn't present in the figure)
5) L275 at C902/903= 2.75V
6)
R275
at C908= 2.75V
no
See diagrams on GSM
Startac/COSMO Lev.4 procedure
No PWR UP