Can't boot laptop after Ram upgrade

[sgmai]

Hi, recently I got new HP elitebook 840 G11 (14 inch). It had 16GB of RAM, so I bought one kingston 16GB 5200 CL42, opened laptop, disconnected battery, put the RAM in and connected battery again.

Now laptop is in state where it won't boot, and the Fan is running at max speed. F5 and F8 LEDs are amber, and power LED is blinking amber if AC power is plugged and battery disconnected. 

Whenever I plug AC or battery in, whole keyboard flashes once, and after ~5 seconds, Fan turns on, along with F5 and F8 LEDs, and thats it. I tried to leave in this state for several hours, nothing happens

I cannot do anything with laptop, neither turn it off or on, unless I completely remove power (battery and AC).

I tried every possible solution I could find, CMOS battery, holding combination of keys, removing RAM, switching RAM, and nothing worked.

I cannot do BIOS recovery either since laptop wont turn on at all, except fan and LEDs, which i cannot turn off except removing all power sources.

Thanks for any help

[TzortzisG]

Hello sgmai.

This sounds like a motherboard level malfunction. I had a similar problem a while back when I upgraded the SSD on a G9 Elitebook. Turned out that when I replugged the battery a capacitor got short-circuited. Unfortunately the post-G8 HP Business models tend to be very complicated and sensitive and upgrading might create problems more often than on older systems. I seriously doubt you'll be able to get this sorted out by yourself. You need to use the warranty.

[Paul_Tikkanen]

Hi, @TzortzisG 

Would the DDR5-5200 memory be the problem?

The service manual calls for DDR5-5600 memory.

Maintenance and Service Guide HP EliteBook 840 14 inch G11 Notebook PC

[sgmai]

Hi TzortzisG, thanks for your reply.

Then what should be the correct way to upgrade these laptops? 

During this upgrade I followed all important guidelines: Unplugging battery, holding power button for ~30 seconds, install RAM, plug battery back in.

As a matter of fact I installed probably over 100 RAM upgrades in my life, never had similar problems. 

[TzortzisG]

Paul, if I'm not mistaken Sgmai has tried reverting back to original hardware but still no dice. This is why I assume something got botched during the upgrade.

Sgmai, I'm not saying you did something wrong. I understand you followed protocol, yet so did I and I still had to remove the capacitor to get the system working again. For some reason the G9, G10, G11s tend to be very very delicate when it comes to upgrading...... It's just a matter of luck in these cases I'm afraid.