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| Elitebook 850 G5 Not turning on, 3.2 boot error | |
|---|---|
| Device | EliteBook 850 G5 |
| Affects part(s) | Motherboard |
| Needs equipment | Phillips Head Screwdriver |
| Difficulty | ◉◌◌◌ Easy |
| Type | General |
Problem description
The 3.2 boot error refers to the caps lock and num lock LEDs flashing 3 times slowly followed by 2 quick flashes. I got this issue when installing a second RAM module, but I also found that this error occasionally appears with only one RAM module.
Symptoms
- Caps lock and num lock flashes 3 times slowly followed by 2 quick flashes
- Screen is black and system will not even enter BIOS
- After roughly 10 seconds, the fan ramps up to 100%
Solution
After numerous trials, I believe I have isolated the issue to the CMOS battery. Simply removing the CMOS battery caused the issue to completely go away in my case, but your results may vary. If you remove the CMOS battery and allow your main battery to completely drain, you may get a boot error that the system time has been forgotten. But, pressing the enter key will continue to boot the system.
Diagnostic Steps
The 3.2 boot error seems to commonly come from RAM errors. First, use https://memtest.org/ or use previously tested memory modules to make sure that the installed RAM is good.
If you still get this error, you may try the steps below.
Repair Steps
- Remove the 10 screws from the back plate. They are captive screws so they stay on the back plate and don't come out.
- Set your finger tips into the grove of the hinge on the back of the laptop. Slowly pry the plate back. There are multiple loud clips holding it in place so don't be afraid to use a bit of force.
- Locate the CMOS battery (which is next to the main battery) and unplug it by gently wiggling its white connector from the motherboard.
- Power cycle the laptop and test if the laptop boots normally. If so, continue to the next steps.
- You may completely remove the battery by prying it. The CMOS battery is only held by small clips, no screws.
- Align the back panel with the hinge placement. Using your palms, press the panel into the back of the laptop by applying pressure around the edges. You will hear several loud snaps as the clips set in place.
- Screw the 10 captive screws back in place.
I do not know the source of this error. I believe there might be a faulty chip connected to the CMOS that might provide a short or other issues to the board.