How to choose which power rail to investigate?

Mrit

New member
Let's say I have a board with some problem on a certain state Six ( G3h, S5, S3, or S0).

Some of the power lines are ok, some have a voltage close to the value expected, but still out or range ( for example 30%-40% below the expected value) , some have a voltage in the mV range, some are 0V.

How would I choose the power rail to investigate first? Is there a criteria to follow in order to speed up troubleshooting?

Also, does the order in which the different power rails appear in the schematics have any relavence to troubleshoot ing order?

As an example, I have a 820-2530-A with problems on S3.

PP5V_S3_REG=5V
PPVTT_S3_DDR_BUFF=0.84V
PP1V5_S3_REG=2.8V
PP3V_S3_FET=15mV
PP3V3_ENET_FET=0V
PP1V2R1V05_ENET=0V

Out of my gut, I would go with PP1V5_S3_REG, as I interpret the presence of a non zero voltage as and indication of something going which somehow get shut down.

Is my assumption correct?
 

2informaticos

Administrator
Staff member
The forum goal is to help on repair process.
For training courses you should contact forum staff.

About 2530 board, if you get 5V_S3, then all S3 voltages must be present.

1V5_S3 is very high and you must inspect U7300 area, especially RA/B.
 
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