So I was hacking my internal laptop monitor (basically I was trying to understand the pinout and try to use it externally). During that I used continuity checker to trace circuitry. It is my old laptop so it was meant for experiments.

Now I did something and I don't know what did I do. Neither internal nor external monitor is not working. I am afraid that by using continuity tool I have damaged some sensitive components.

Is there a way to check approximately where the issue is - gpu, cpu or systemboard?

I know the following points may mean nothing, but maybe they will be usefull:

  • GPU and CPU heat up
  • Motherboard supplies power to VGA and internal monitor sockets (including inverter)
  • I am testing without all unnecessary peripherals (just ram, motherboard(&its intergreted components), cpu, gpu). It should show blinking bar. Not monitor is not even started(stays on sleep mode)
  • Monitors have been checked
  • I have oscilloscope, external power supply - if checking testpins is the case, I could do it.
  • I cannot replace cpu or gpu - buying spare parts and checking wouldn't be the best idea.

Please ask any additional information you require. I will try to answer.

  • \$\begingroup\$ If you can't replace the CPU or GPU, why would you care where the problem is? \$\endgroup\$ Commented Aug 27, 2012 at 22:27
  • 2
    \$\begingroup\$ Isn't it interesting to know, where the issue is? I am curious :) \$\endgroup\$ Commented Aug 27, 2012 at 22:46

1 Answer 1


It sounds like you may have shorted your GPU. Try probing any lines going to the chips, and seeing if they have any signal. Be sure to be careful when you are poking around and the computer is on. Also make sure that the chips have some type of heat sink if they need one.

Personally I do not know of anyway of repairing a broken gpu (aside from replacing the motherboard)

In my opinion, I would consider the laptop scrap, and salvage any interesting looking parts (I like the keyboards and mice). Please make sure to destroy the Hard drive if you chose to scrap it (a good game of Hard Drive baseball is always fun!)

As for figuring out the pinouts on the monitor; I would do some DEEP research into the model number. About 75% of the time you can find some sort of semi-useful datasheet on your laptop components. If you have any trouble with this, be sure to post the question here.

  • \$\begingroup\$ Is it somehow possible to confirm that the issue is in the GPU? I believe probing ANY lines from GPU won't work, will it? If you want me to check if it's even doing at least something, then I must say that it warms up, therefore I believe it is. \$\endgroup\$ Commented Aug 27, 2012 at 20:38
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    \$\begingroup\$ There is no way to confirm without a doubt that it is the GPU short of pouring over dozens of pages of schematics that are not public. The pins (atleast some of them) should be available to be probed on the bottom side of the board, under the chip. Heating up means nothing if there is no useable output. \$\endgroup\$
    – Reid
    Commented Aug 27, 2012 at 21:18
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    \$\begingroup\$ Booting headless (with remote access) and querying the status of graphics system components from software might be informative. \$\endgroup\$ Commented Aug 28, 2012 at 6:25

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