5-18 Troubleshooting Charts: DC Supply Failure
5.4.4 DC Supply 1.85 Volt Failure
V_SW_1.85 supply
Is radio
drawing > 100mA
from battery
or power
supply?
Remove
VOCON
shield(s)
Voltage
level
correct?
Replace
VOCON
board
Yes
Yes
Yes
No
No
No
Verify connectors
J1001 to P101 are
seated correctly
and not damaged
Verify battery or
battery eliminator
contacts are
connecting to the
RF board’s
spring contacts
Check U6508 and
verify enable input
at R6543 is present
Verify SW_B+ is
present at C6565
Verify
UNSW_B+ is
present at
Test Point:
F_UNSW_B+
Remove RF board
and ohm across
P101
(pins 28 thru 36)
and B+
(battery contact)
at the RF board
and verify fuse
F200 is intact
(i.e. not blown)
Check
Q6501
Replace
VOCON
board
Check Q6502 and
Q6503 for damage
Replace
VOCON
board
Voltage level correct
for V_EXT_1.85
at C6568?
MAKO
damaged
Replace RF
board
No
Yes
No
Remove
VOCON
shield(s)
No
Verify all other voltages are present
(i.e. 3.6, 1.4, etc) since if they are
absent, radio IC’s maybe preventing
MAKO from turning on and
generating V_EXT_1.85
No
Check if OMAP
U6302
is drawing
excessive curent
from V_EXT_1.85
thru E6501
No
Replace board
with damaged
connectors
Are connectors
J4001 to P2001
shorted or
damaged?
Yes
Refer to other
troubleshooting
charts for these
voltage supplies
Check for
damage to
Q6507
Check for
damage to
voltage
translators
U2202, etc
Check for
damage to
MUXES
U6601, U6103,
U6104, U6105
Check if
CPLD U6101,
Audio codec U6605,
DDR U6301, or
FLASH U6302
are drawing excessive
current from V_EXT_1.85
No No
No
NoNo
Yes
Check for
short to GND
at J2001-10,
P2001-28
Replace
Expansion
board
Check for
short to GND
at J1001-6,
J2101-29,
J2304-12,
J4001-28
No
Check if
MACE U2501,
eMMC U2301,
BlueTooth U2401
are drawing excessive
current from V_EXT_1.85
Check for
damage to
voltage
translators
U2406, U2407,
U2408, U2409,
U2410, U2478,
U2414, U2473
No
No
No
No Yes Yes
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