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Lenovo G500 (model name 20236) - accidently disconnected the Intel video card.
#1
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Hi,

I think i have bricked my Lenovo G500 laptop.
The BIOS has been modded (whitelist removal and unblocked advanced menu).

I have been stupid and disconnected the Intel video card.  Sad

In an attempt to enable the AMD GPU in the laptop i forgot about the warning to not disconnect the Intel video card... Now the laptop turns on with a black screen (don't even see the back-lighting turning on) and no further activity whatsoever... After a minute the CPU fan starts spinning and that's about it.

I have already tried this procedure without any progress:

1) remove AC jack, Main Battery, and CMOS Battery
2) remove HDD and all DIMMs
3) wait 10 mins
4) press and hold power button for 30 sec.
5) install CMOS Battery and one DIMM only, inject AC jack (without Main Battery!)
6) try to boot your laptop.  

I don't understand why clearing the CMOS does not restore some reasonable defaults...
Aren't those settings stored in de CMOS RAM chip?
Even disconnected the CMOS battery (and other power sources) overnight with no luck.

Is there anything else i can try? Do I need to reprogram the BIOS EEPROM?
What's a good programmer?
Can the programming be done in-circuit or do i need to de-solder the EEPROM chip first?
I have all the necessary tools and experience to work on PCBs.

I still have all the files generated during the modding process.

Here are some screenshot with additional info:
   
   

Any help appreciated.
Thanks in advance.
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#2
I've done some research and found that on modern PCs BIOS parameter are likely NOT stored in volatile RAM. That could of course explain why removing the battery had no effect on the problem. From what i've found the battery is only used for the RTC.

I'm trying to figure out where the laptop stores it's BIOS parameters and more importantly how reset those to some reasonable defaults and bring the laptop back to life.

Any help would still be appreciated
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#3
Laptop: Lenovo - G500 (20236)
Mainboard type = LA-9631P

I'm getting a bit lost in looking for a way to clear (load defaults) BIOS parameters from so called CMOS memory?
From what i've read the storage of BIOS parameters could be in the south-bridge...
Some jumper, pads or pins to reset the CMOS BIOS parameters?
Any other way to unbrick the laptop?

Greetings,
bootpanic
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#4
Yesterday I found schematics for the LA-9631P mainboard of my Lenovo G500 laptop and i was able to locate the Clear CMOS pads (CLRP2) underneath the hard-disk (see picture). Shorting the Clear CMOS pads and powering the laptop on / off made no difference...

I don't understand why clearing the CMOS did not solve the problem.

Did something break in disconnecting the Intel video by setting a BIOS parameter?
What is going on?

Any more info by one of the experts here would be greatly appreciated.

Best regards,
bootpanic


   
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#5
Disassembling the laptop and re-flashing the BIOS with a programmer fixed the problem.

Best regards,
bootpanic
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