Go-No-Go Test of VGA/GPU Outputs

Howdy,

I'm bran' new to the forum. My electronics knowledge is rusty and limited. I do pretty well with computer hardware and software in my business. I wonder if there is a simple it-works-or-it-doesn't test for VGA/GPU outputs. Basically I would like to test for blank monitors when they're fer sure powered up and MoBo is doing its thing but absolutely no image. I have to be careful of cost as this would not be a very common need. So is there a way of testing such with a multi-meter? that would be great. If I need a frequency counter, maybe I could find the time to build a kit if it comes with suitable instructions/data.

Any help will be much appreciated,

scruf

Are you trying to test the graphics card or the monitor?

You could certainly stick a frequency counter on the sync lines of the VGA output - the horizontal synch should read something in the 10's of khz if it's working, 60hz or so on the vertical sync (around 1V peak) and nothing if there's no signal.

For the monitor, they sell inexpensive VGA "monitor testers" - https://www.cdadapter.com/vgaplus.htm

So you're saying that booting up the mobo or PC (with the video card/on-board video in question) into a known-working-good monitor (or booting up a known-working mobo/PC into the suspect monitor) doesn't give you the information you need? I mean, if you can't see the PC BIOS boot sequence/post at the lowest level, that pretty much guarantees you that the video is dead (and not worth looking at any further, given the commodity prices we are talking about for most video cards and motherboards). What am I missing (and I must be missing something big here, because this question seems like a no-brainer)?