Dell Latitude E5450 LA-A901P no BIOS voltage

[JaroTech]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

Are you ready to try a special test?

[BMCappelletti]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

Are you ready to try a special test?

Asking like that I'm not sure. :p
But... go ahead. The worst I can do is give up.

[JaroTech]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

So far we know with a charge of 100K ohms you have 3.3V on the pin 3 of UZ8 without the chip installed. With the original or an equivalent, you have zero volt on pin 3. My theory is the chip UE2 can't handle the current from the UZ8 and go directly to zero volt. With the EM5209 still on the board, cut the trace from the pin 3 and connect it to pin 2 so you will isolate pin 3 from UE2. You should have 3.3V on pin 14 of UZ8 and see what happens from this.

[BMCappelletti]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

So far we know with a charge of 100K ohms you have 3.3V on the pin 3 of UZ8 without the chip installed. With the original or an equivalent, you have zero volt on pin 3. My theory is the chip UE2 can't handle the current from the UZ8 and go directly to zero volt. With the EM5209 still on the board, cut the trace from the pin 3 and connect it to pin 2 so you will isolate pin 3 from UE2. You should have 3.3V on pin 14 of UZ8 and see what happens from this.

Done. Indeed now I have 3.3V on it. And 3.3V in the BIOS chip. But it still does not post. Power light comes up and goes down after over 10 seconds. 13 or 14 seconds maybe.
No fan spin.

[JaroTech]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

So, what I deduct from this test, the chip UE2 is defective. "This is my final answer", it's from a program "Who Wants To Be a Millionaire" from the TV series.

[BMCappelletti]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

So, what I deduct from this test, the chip UE2 is defective. "This is my final answer", it's from a program "Who Wants To Be a Millionaire" from the TV series.

Ok. Not worth trying to replace it. Will use it for spares.
Was fun to try diagnose it.
Thanx a lot.

[JaroTech]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

I'm not an expert with laptop but I know how to understand a schematic, if someone else have a better answer for this problem, be my guest.

[BMCappelletti]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

I'm still up for other tries.

[mcplslg123]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

Very likely chip UE2 is defective but to be 100% sure, you can remove UZ8 once again and inject 3V on pin13-14 and notice the current consumption.Is anything slightly warm?

[BMCappelletti]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

Very likely chip UE2 is defective but to be 100% sure, you can remove UZ8 once again and inject 3V on pin13-14 and notice the current consumption.Is anything slightly warm?

Tried it. Consumption is only 0.056 amps. Not enough to warm anything.

[JaroTech]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

Another try, reconnect pin 3 of UZ8 to A_ON and remove the resistor RZ42. Check the voltage on A_ON.

[BMCappelletti]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

Another try, reconnect pin 3 of UZ8 to A_ON and remove the resistor RZ42. Check the voltage on A_ON.

Pin 3 of UZ8 is A-ON. What do you mean by "reconnect" it?

[BMCappelletti]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

Anyway... the board does not have RZ42 and RZ41 installed.

[JaroTech]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

In post #23 I said "cut the trace from the pin 3 and connect it to pin 2 so you will isolate pin 3 from UE2" that's what I was referring to.

[BMCappelletti]

Re: Dell Latitude E5450 LA-A901P no BIOS voltage

In post #23 I said "cut the trace from the pin 3 and connect it to pin 2 so you will isolate pin 3 from UE2" that's what I was referring to.

Oh sure. Yep. Forgot about that.
But... no resistor there anyway.

[ameesh.p]

I have same issue on this same motherboard all replays help me lot . finally i pre heat UE2 chip then all voltages ready . bios voltages comes. and working well. thank you all.....