Lenovo 80nj 3.3v Alw power ic Replacment

[garrymc123]

Hi, Guys, I removed pu401 .3.3 volts power ic SY8208BQNC as it was getting hot and had no 3.3 volts on the motherboard but before i replace it on pin 5 vcc on the motherboard im getting continuity to ground is this normal i just want to double check before i put on the new power ic on .Thanks In advance

[techtiger]

pin5 SY8208BQNC not VCC it's LDO +3VLP check the cap PC412 or your output from the point is short, check pin2 also same voltage goes there

[garrymc123]

Thanks Techtiger for your help. i'm a bit confused according to the pin out on the datasheet which i have attached its says vcc on pin 5 second pin down.I will check what u have suggested and see if i can find the short. Thanks

[techtiger]

Originally Posted by garrymc123

Thanks Techtiger for your help. i'm a bit confused according to the pin out on the datasheet which i have attached its says vcc on pin 5 second pin down.I will check what u have suggested and see if i can find the short. Thanks

Yep as for the Dataset SY8208BQNC pin5 VCC or LDO

[garrymc123]

Aww i see now i was just going with what the pin said sorry. How will i find out where that pin goes as its just a wee silver dot on the other side of the motherboard to find the short . Thanks

[piernov]

I've seen this mistake a lot recently but indeed this is very confusing.

Pin assignment of SY8208 is not the same on the A, B, C and D variants. Datasheet shows only A variant. Note that several Compal schematics have the wrong footprint for SY8208 (as it is the case here on Compal LA-B092P I think). Compal LA-9535P has the correct footprint for SY8208B and SY8208C. Also boardview for Compal LA-9535P is available if you want to make sure which pin is which on the chip.

[techtiger]

Originally Posted by piernov

I've seen this mistake a lot recently but indeed this is very confusing.

Pin assignment of SY8208 is not the same on the A, B, C and D variants. Datasheet shows only A variant. Note that several Compal schematics have the wrong footprint for SY8208 (as it is the case here on Compal LA-B092P I think). Compal LA-9535P has the correct footprint for SY8208B and SY8208C. Also boardview for Compal LA-9535P is available if you want to make sure which pin is which on the chip.

thanks Piernov for this information

[on/off]

More info:

Originally Posted by fzabkar

The SY8208 part was manufactured by Silergy (it was also the subject of a patent infringement case). AFAICT it has at least three versions -- adjustable (DQNC), 3V fixed (BQNC), 5V fixed (CQNC).

Note that the suffix is VERY IMPORTANT.

he SY8208DQNC incorporates an adjustable step-down switchmode converter with a feedback reference voltage of 0.6V.

The SY8208BQNC appears to be a fixed 3V converter, and the SY8208CQNC appears to be a fixed 5V converter.

[garrymc123]

Thanks, guys for the information it was very helpful. piernov where can I get the board view for this motherboard I have downloaded board view software thanks for the link

[garrymc123]

Still in the process of repairing this motherboard anyone know where I can download the boardview for this model Compal LA-9535P Piernov said it is available ..Thanks

[on/off]

Boardview:

[garrymc123]

Just realised its the wrong schematic for my board bit it is similar tho mine is _la-b092p_r1.0_ anyway i couldn't find anything shorted so i injected 3.3 v on that line that was short to ground and it was the big chip that heated up is this my problem chip?

[techtiger]

Originally Posted by garrymc123

Just realised its the wrong schematic for my board bit it is similar tho mine is _la-b092p_r1.0_ anyway i couldn't find anything shorted so i injected 3.3 v on that line that was short to ground and it was the big chip that heated up is this my problem chip?

Test pin 9 U11 for resistance ,Your SIO U11 getting heated up Remove it up from the Mob and test if the short is still there

[Ilidio PS]

Originally Posted by garrymc123

Hi, Guys, I removed pu401 .3.3 volts power ic SY8208BQNC as it was getting hot and had no 3.3 volts on the motherboard but before i replace it on pin 5 vcc on the motherboard im getting continuity to ground is this normal i just want to double check before i put on the new power ic on .Thanks In advance

good afternoon,
I really have defect what do I
help me please ??