Dell N010 Power IC Problem

[mikeluke80]

Hey,

Hoping for some knowledge share on a little problem i have.

Trying to repair a No Power Dell N5010 down at board level and ive come accross an issue i havent seen before.

I have +PWR_SRC from the adapter and to all the places it should be but i have no 3.3v, 5v or 15v coming out of the RT8205B power IC.

The question i have is, does that mean that it is the IC that is caput or can there be any other influences to stop it regulating the voltages down? Its not getting hot or anything and i cant see any obvious shorts.

Any help would be appreciated

Mike

[khaahk]

Re: Dell N010 Power IC Problem

If RT8205 is getting power on pin 16, then at least VREG3 and VREG5 should be present. If not - either bad ic or overcurrent (should be hot).

[ktmmotocross]

Re: Dell N010 Power IC Problem

there are one or two mosfets right after the +PWR_SRC and fuse. check it

[HarryPK]

Re: Dell N010 Power IC Problem

If RT8205 is getting power on pin 16, then at least VREG3 and VREG5 should be present. If not - either bad ic or overcurrent (should be hot).

you are right...

[mcplslg123]

Re: Dell N010 Power IC Problem

If Charging Ic Isl88731 is bad,then also no 3v/5v. So check it

[mikeluke80]

Re: Dell N010 Power IC Problem

Thanks for the replies,

Ive attached the Schematic, on this mobo the I/O board which has the power connector on is seperate and i cant find the details for that on the scheme. There is one power mosfet after the DC jack which has 19.7v coming in on pins 1,2,3 & coming out of 5,6,7,8 but the gate voltage on 4 is only 3.1v ?

Ive just found that on page 46, i have 3.3v ALW coming into the FET Q4601 so it must be there somewhere.

Thanks

[mikeluke80]

Re: Dell N010 Power IC Problem

Thanks mcplslg123

Ive had a quick look at the charger circuit, i have 19.7v coming into the Mosfet PU4503 and also a gate voltage of 19.7v but nothing coming out, i presumed thought that was because it wasnt charging the battery?

[ktmmotocross]

Re: Dell N010 Power IC Problem

it is P-channel mosfet

[mikeluke80]

Re: Dell N010 Power IC Problem

khaahk so i can confirm that i have VREG3 & VREG5 out of the R8205. These are 3.3v_ALW_2 & 5v_ALW_2.

Just cant figure out why i havent got anything else out of the controller. Does it need a run signal from anywhere?

[khaahk]

Re: Dell N010 Power IC Problem

Check resistance on PL4601 and PL4602 relative to gnd. SMPS will shut down if overcurrent detected. It should not be low ohms. If possible change the rt8205 to be sure.