755CDV blank screen, doesn't boot

[Half-Saint]

Hi,

today I was given a 755CDV in good condition. but of course it's not technically flawless. Upon lifting the keyboard I noticed that the main battery has leaked badly. I haven't checked the motherboard so I don't know how bad it is.

The first problem is that there's no picture when I turn it on. It beeps and the backlight is on but you can't see anything on the screen. It works fine connected to an external monitor.

The second problem is that the computer is stuck at RAM count. It just sits there.

Any ideas?

Cheers

[jack_zhan]

No picture but backlights on ---> loose connection of the LCD panel suspected. Try reseating the panel. Needs to take the machine apart.

Stuck at RAM count --> bad memory chips and/or unsupported RAM type. Try booting without any RAM cards in the RAM slot. If the problem remains, you might need to replace the system board.

Also, please provide more details about the beeps, e.g. long or short, how many times, etc.

You may refer to the HMM, which can be downloaded here:
http://download.lenovo.com/ibmdl/pub/pc ... tpvol2.pdf

Jack

[Half-Saint]

I get one beep. Removed the IC DRAM Card and everything else that I could.

Got past RAM count only to get an error I9990305 and stuck again.

The computer makes some weird screetching noise. Can't determine if it's the speakers.

If I put the HDD back in, I don't get that abovementioned error but I get stuck at RAM count again.

Tried reseating the flat LCD cables but didn't help.

Any more ideas?

[Half-Saint]

Update:
- managed to get into BIOS and do a system test

I get the following errors:

DISPLAY:
DEV 051
ERR 50
FRU 0041

HDD-1:
DEV 017
ERR 23
FRU 6010

I imagine the video card is integrated onto the main board and the hard drive is toast.

[jack_zhan]

The error code I9990305 is nothing to worry about. It's "No bootable media". It is expected as you removed the hard disk. And with nothing to boot from the machine can only hang. You can get past the RAM count? Without hitting Esc while it is counting and got the correct "7808KB OK"? Then your onboard memory is intact. Currently we don't know if your RAM card is working, so let's put it aside until other things are repaired.

The codes from the test:

FRU 0041 --> Bad video card. But it can still work fine with an external monitor. Interesting.

FRU 6010 --> The hard disk is toast. You are right. Get a bootable CD-ROM and try booting from it. See what happens.

Still don't know why booting with hard disk attached the system hangs at RAM count. But your system board might need to be replaced, for this symptom and also the suspected bad video card(yes it is soldered on the system board).

Update: one beep and blank LCD --> Bad LCD and/or bad video card and/or bad DC/DC card. DC/DC card is the small board inside the screen case near the hinges. If you want to replace things, first the LCD, then the system board, then the DC/DC card.