Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

[reessi]

Hello,

Since looking at this laptop it has only posted twice after numerous times.

First thoughts were corrupt bios, I unsoldered it and tried some bios files off here for 3500 model and I extracted the bios from the official HP download to no avail. I have put a request in the bios request section as I am unsure if the one off the HP site should work or I need a dump from a working board.

Even then does the bios need board specific details editing into it, should it post with errors if that were the case?

Next I warmed up the combined CPU/GPU lightly with 200c air as this always has brought faulty GPU's to life tempererally but to no avail again.

What about the Embedded Controller (IT5570E), can these be intermittent. I have replaced these chips in the past successfully but this was after they had gone short circuit...

Is it worth replacing or are they either working or not. Since it has posted twice then maybe it is working?

What else can I check?

I have replaced ram and removed the SSD during testing...

When it turns on, there is no heat from the processor, voltages appear normal, 5v, 3v etc to bios and embedde controller.

Any schematic available?

There is no activity on the h/d led on the side of the laptop when SSD is installed.

The fan never spins, I cannot remember if it did on the 2 occasions it posted..

The battery is charging..

There is no output to an external monitor.

I have marked 3 coils with no voltage on the pic, I do not know if that is abnormal as I do not know what they power.

Many thanks.

[reessi]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

Is there anyway to check if the bios is corrupt? I have my dump I could upload?

[mon2]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

This one?

https://www.badcaps.net/forum/showthread.php?p=1073747

[Sephir0th]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

Even 1.2V VDDQ not coming up...? Smells like a issue with the RAM-circuit, -socket or even with the module itself. Ruled out bad Memory module...? Might also a good idea to do a detailed visual inspection.

[mcplslg123]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

I think there is no dc-dc transfer happening on 3V/5V circuit. may be enable for dc-dc conversion is missing.

[reessi]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

This one?

https://www.badcaps.net/forum/showthread.php?p=1073747

Ah sorry, I must have only searched the laptop model and not the board number..

Normally I search both..

[reessi]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

I've definitly ruled out ram module. Tried known working ram that works in other machines. I'll check again all the voltages this evening. Because it posted twice this is confusing, I've never seen the power rails work intermittently..

I have done a thorough inspection of the both sides of the board under the microscope, the board is immaculate..

The underside has very little components..

[reessi]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

If I replace the super I/O controller does it need to be programmed? It is IT5570E. Are there any datasheets for this chip?

Nothing in google...

Cheers.

[mcplslg123]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

I think there is no dc-dc transfer happening on 3V/5V circuit. may be enable for dc-dc conversion is missing.

Not answered yet

[mcplslg123]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

If I replace the super I/O controller does it need to be programmed? It is IT5570E. Are there any datasheets for this chip?

Nothing in google...

Cheers.

Yes, IT5570 needs programming with SIO programmer.

[reessi]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

Not answered yet

Sorry late replay. I am not sure what you mean? In the photo I uploaded I labelled the 3.3v and 5v coil/regulators. They both turn on when the laptop is turned on!

Am I missing something?

Also it does post very rarely like once a month, I don't think a regulator goes intermittent from my experience or can it?

Thats why I was focusing on the Bios/IT Chip and the CPU.

Cheers.

[mcplslg123]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

Even 1.2V VDDQ not coming up...? Smells like a issue with the RAM-circuit, -socket or even with the module itself. Ruled out bad Memory module...? Might also a good idea to do a detailed visual inspection.

You've not confirmed whether this 1.2V rail for ram comes up when its not booting. If this rail doesnt comes up, then focus should be on the requiremnt of ram regulator.

[reessi]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

Hello, I'm back on this.

I can confirm that the RAM power rail 1.2v is not present. There is no short at the coil. Tested with a meter and 1.2v from my bench power supply. It takes nothing with no ram and ~30mah with a ram stick in.

Also there is a power supply above the APU (see my picture) which I believe is the APU power rail but the nearest chip I cannot find the datasheet.

Chip markings:

5v=7J
J4Q


I believe it is a power supply as has similar markings (ML=7J) as the one next to the MSATA power supply which is working.. 1.8v.

So for both supplies to not be up and not short implies they are not being enabled, is this the job of the SUPER I/O?

I'm not sure where to go from here?

I am still confused why it booted on the 2 odd occasions !

[mcplslg123]

Re: Occasional POST - HP 14-CE3600SA - G7AL-2G - DAG7ALMB8C0 REV.C

Yes the chip marked 5V=7J is cpu power regulator and you should'nt probe it as cpu core will come after all its requiremnts are met.Check whether VCCSA/PCHPOWER coils have voltage? Check voltage on pin 7/8/9/4/11/12 of PU12(after turning on)