Error 502: impossible turn on the notebook

[ALDO28]

Two months ago my pc's battery started giving problems.

Without being plugged in the pc would not turn on and could not stay on (if I tried to turn on the pc without it being plugged in, it would not turn on. If I turned it on keeping it plugged in, and then unplugged the power supply, it it turned off immediately. )

Over time it happened that when I turned it on, a black screen appeared with a CMOS 502 error.

I clicked enter.

The PC shut down and restarted automatically.

Turning on the pc so I found myself with the wrong data and time but at least it started.

A few days ago I went to replace the battery.

I specifically asked to change both the main one and the internal one.

After a day they called me telling me that my notebook doesn't have an internal battery separate from the main one and that therefore also the Bios, date and time control depended on the main one.

Being pratically at 0% of usability, it was normal that the pc was not able to handle the CMOS and reset it every time. However, I go to collect the pc from assistance and at the time of collection I find myself in this condition: The pc can turn on without being connected to the current and the battery lasts about 3h. The only problem is the fact that when I turn it on it gives me the CMOS 502 error and then I have to click enter, it turns off and on again automatically (as before the change).

I say: well it doesn't matter, the important thing is that I can also use it outside the home without it being connected to the current.

After 1 day of use, however, I find myself in a disastrous situation: if I try to turn on the PC without it being connected to the current, first it gives me the CMOS 502 error, then I click enter, it turns off, turns on again and then immediately after, while  it's in the black loading screen with the white HP logo, a kind of BEEP is heard from inside the pc and it shuts down.

And there is no way to turn it on.

If, on the other hand, I plug current in, it turns on with the 502 error. (so i have to click enter... but at least it start)

But the battery works, in fact, after accessing it, I can safely unplug the cable and use it for about 3h.

Strange thing, after turning on the pc (keeping it connected to the current, because I repeat, otherwise it won't turn on) it's as if it had forgotten the accounts logged into the pc, because to access windows I have to put username or email and then password.

Please help me, I really don't know what to do.

I ran Hp hardware tests on battery and ac charger and they are perfect.

I have updated the BIOS to the latest version.

I even reset it with WIN + B key on startup.

What could it be?

[Nal_NR · Accepted solution]

Hi @ALDO28,

Welcome to the HP Support Community. 

I'd like to help!

Fabulous analysis. Spectacular diagnosis of the issue before posting. Kudos to you for that. You've done a remarkable job performing the steps. 

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