Ericsson R250s PRO Troubleshooting Instructions page 11

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Measure VRAD on N412 pin5, VVCO-N410 pin5 and VRPAD-N411 pin5 volt-ages ~3.8V.
3.5 The phone does not start in the flash programmer
Disassemble the phone and check for liquid damage.
No further action should be taken for a liquid damaged telephone.
Make sure the system connector pads are not damaged or burned.
•
Measure the resistance of R421 ~ 0.1 ohm.
Mount the board in the fixture. Start it up and keep it running by keeping DCIO high.
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Check VDIG-N702 and VDSP-N701 voltage 3.2V.
•
Check the power reset (PWRRST) voltage at C710 >3V
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Measure the voltage VRAD-N412 pin5, VVCO -N410 pin5 and VRPAD-N411 pin5 voltage
~3.8V, fig.
4/00021-2/FEA 209 544/18 D
If any of the voltage are too low, measure the resistance from it to ground (VDIG -
>500 ohms, VDSP - >25 kohms).
If the resistance is correct, replace the corresponding regulator.
If it is too low, send the unit on according to the local company directives.
If any of the voltages are too high, replace the corresponding regulator.
If any of the voltage are incorrect, measure the resistance from it to ground (>50
kohms).
If the resistance is correct, replace the corresponding regulator.
If that does not help, or the resistance still is too low, send the unit on
according to the local company directives.
If R421 is replaced, the charging function has to be verified. If it's incorrect, send the
unit on according to the local company directives.
If any of the voltage are too low, measure the resistance from it to ground (VDIG >500
ohms, VDSP >25 kohms).
If the resistance is correct, replace the corresponding circuit, VDIG - N702,
VDSP - N701.
If the resistance is too low, send the unit on according to the local company
directives.
If any of the voltages are too high, replace the corresponding circuit.
If it is lower, check R704 ~0 ohms and R725 ~100 kohms.
If they are ok, first replace C710 and if it does not help, replace N703.
If any of the voltages are incorrect, measure the resistance from it to ground >50
kohms.
If it is correct, replace the corresponding circuit.
If the resistance is too low, send the unit on according to the local company
directives.
Standard Trouble Shooting Instructions
11(35)