Dell 3421 motherboard 5J8Y4 does not turn on

[ruletero]

Hi everyone

I have 5J8Y4 Dell 3421 motherboard it does not turn on.

I don't have power led, I checked power secuence and I have 3v alw, 5v alw and It's 3V_5V_POK signal but Kbc does not release PM_RSMRST#.

I don't know what to do now, Please help

Raul

PD: Sorry for my bad English

[razu]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

reflash the bios, with new file

[ruletero]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

Sorry

I forgot to say it, the first I do was to flash the bios without change.

Thanks.

[mcplslg123]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

The kbc itself can be bad-so if you have a spare kbc, replace it first.

[Luaina]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

First check that the KBC is properly powered (Test all the voltages that goes in it).

[pyry]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

que voltajes tienes en el charger pu4005
en los pines
20
6
5
12
16

[ruletero]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

First check that the KBC is properly powered (Test all the voltages that goes in it).

pin 104 vref 3.27v
pin 19 vcc 3.19v
pin 4 vdd 0v ???
pin 114 vbkup 3.12v

I guess it is fine...

[ruletero]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

que voltajes tienes en el charger pu4005
en los pines
20
6
5
12
16

20 19v
6 2.55v
5 0v
12 2.76v
16 6v

I guess it's fine too.

Thanks

[mcplslg123]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

pin 104 vref 3.27v
pin 19 vcc 3.19v
pin 4 vdd 0v ???
pin 114 vbkup 3.12v

I guess it is fine...

PIn 4 VDD on kbc must be 3.3V. Measure again and if not present, then you need to find out why voltage not present on pin4. This is the input for kbc-so kbc wont work properly without this voltage.

[Luaina]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

pin 104 vref 3.27v
pin 19 vcc 3.19v
pin 4 vdd 0v ???
pin 114 vbkup 3.12v

I guess it is fine...

3.3v Vdd is S0 power rail. It is present only after you press the power button ( It figures among the last volatge that comes in alongside the processor volatge). I recommend replacing the IO but you can nevertheless inject t 3.3v there and see what happen( Does this injected voltage goes down? something hot?).

[pyry]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

friend first check that all the signals are reaching the kbc for example
feed that we already know is fed
pin 99
pin 85
pin 17
pin 73
pin 93 to change from 3.3v 0v and go up to 3.3v when you press the power button
for that you can bypass pin 4 with the two of PWRBT1 for an instant only and at the same time measure the leg of kbc 93 that the change of state is coming to the kbc of the power button

[ruletero]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

PIn 4 VDD on kbc must be 3.3V. Measure again and if not present, then you need to find out why voltage not present on pin4. This is the input for kbc-so kbc wont work properly without this voltage.

I guess that signal is not present en s5 state, but I'll check it again.

[ruletero]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

At the moment I am reviewing the S5 status because neither the power led turns on, but thank you very much for the recommendation.

[ruletero]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

3.3v Vdd is S0 power rail. It is present only after you press the power button ( It figures among the last volatge that comes in alongside the processor volatge). I recommend replacing the IO but you can nevertheless inject t 3.3v there and see what happen( Does this injected voltage goes down? something hot?).

I'm going to order the KB but, does it need to be programmed? or only I must to change it.

Thanks for the help

[Luaina]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

I don't think it's a programmable KB. You have just to replace it.

[mcplslg123]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

I guess that signal is not present en s5 state, but I'll check it again.

Yes, schematic clearly tells it S0 state power. so wont be there without turning on.

[mcplslg123]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

I'm going to order the KB but, does it need to be programmed? or only I must to change it.

Thanks for the help

NPCE885 is not programmable-so just replace it and see if RSMRST appears.

[ruletero]

Re: Dell 3421 motherboard 5J8Y4 does not turn on

Ok

I ordered the chip I have to wait about 3 weeks for arrive it.

Thanks all, I'll inform you the results as soon as I can.