I thought about this since reading it last night. Best guess is that the graphics card is getting insufficient power.

Some advanced cards have a separate power feed using a slim 4-pin connector- even if the same MB in a lower-rated PSU ran power fine, a different one may limit power fed to the MB as a safety limit, so now you need a separate plug for the GPU even though you didn't before.

Alternately, the new power supply isn't feeding its full promised capacity despite its rating. If you can swap for a different PSU, that'd be a good test.

 

First- I mentioned a separate power feed for the video card- obviously this wouldn't matter for the onboard, but I'm curious if there is such a port on the card.

I assume the monitor works when connected to another PC (either tower or laptop). If you haven't tested it, do so. It may be a matter of stripped leads/bent pins on the monitor's cable. (Also nifty for confirming that the power cable isn't loosely connected and thus causing a circuit spike).

With the onboard video not working, I'm beginning to suspect BIOS or jumper interference. Jumpers are easier, as they can be checked without a working screen. What you're looking for is a jumper setting that assigns the video path to use a particular GPU, rather than being set for 'Auto'.

Playing with jumpers requires guidance from the mobo manufacturer's manual. They're often available online.

BIOS is a chicken and egg problem- you can't navigate if you can't see. If possible, I would suggest trying an older monitor (preferably not wide-aspect) to test for at least basic function.

 

Jumper: a small bit of copper shaped to fit around two pins, wrapped in a rectangle of plastic- you use them to complete a circuit between two pins on a circuit board. Changing the jumpers is a physical way of changing the 'programming' of the system board. Not to be messed with haphazardly.

(I may be a bit retro in thinking they're still in regular use. Check the BIOS first.)

Since you can see the BIOS using the older monitor, you'll want to look through the options to see if the video modes are limited, if the system is set to run in a power-saving mode or any other ginchy settings that may throw off the use of the big screen.

This is where searching Google for specifics on your model of motherboard combined with your monitor may realize some insightful guidance.

 

Sounds like your video cable is dead.

 

You didn't specifically mention swapping your video cable out. Given your reply I'm assuming that your video cable is hard wired into your monitor. It doesn't really matter since you've ruled out the cable anyway.

One thing about onboard video that you may not know and might help with troubleshooting. Motherboards don't automatically turn their onboard video on and off by checking when there's a video card plugged in. I've always had to do this manually.

eg. When I was working on a PC whose video card had died, I yanked it and plugged the monitor into the onboard video instead. The screen stayed blank. Because there was no video feed I couldn't get into the BIOS to enable the internal video option. It wasn't until I reset the motherboard BIOS with the "clear CMOS" jumper that the onboard video started working again. Onboard video is always on by default, and must be turned off in BIOS if you want to use an external video card.

You might already know all of that, but if you didn't then it'd really screw up your troubleshooting work.

I've come across motherboards with dead onboard video too. In that case I was only able to turn on the external video with another jumper. Look for a Primary video or PCI/AGP video jumper in the case that you ever need to do that. It'll be listed in your mobo manual.

 

I've got a theory.

Your old micro-ATX and new midi are exactly the same computer, just in a different case, right?

Assuming that's correct, the onboard video may have been damaged during the transfer to the new case [physical knock, pre-existing bad solder, static, etc.] and so now the onboard video isn't working.

You have a discrete video card. I wish you could just plug it in and then set a jumper to switch primary video to the card...

This theory doesn't account for why the new mobo also doesn't work with the monitor. It's possible that you're dealing with two separate problems here. I've had a string of bad luck like that bite me in the arse more than once. It's usually turned out to be a flaky device and a flaky cable working in unison to drive me insane.

What's the model number of the motherboard? Maybe we can find an alternate way to switch primary video.

When you tested the monitor with the new mobo did you try both the onboard video and discrete video card and change the primary video setting too?

It won't hurt to try it, but I can't see any point in doing it either.

Regarding your new mobo, did you ever get video working on it with a different monitor [eg. the CRT]? If it can spit out video to the CRT but not your usual monitor, then the problem is definitely on the monitor side of the equation.

If the new mobo fails with both monitors, then the problem is probably with the motherboards. The new mobo would be either broken, or had a non-default primary video setting [which could have occurred a couple of ways] in which case you should reset its CMOS to check.

What's the make and model of the new mobo? Just calling them 'mobo' and 'new mobo' is bound to lead to a mistake in my ramblings somewhere.

 

Had a similar problem not too long ago, the video cable itself would only work with a certain monitor and setting combo. Bought a newer cable, problem went away.

Make sure in your CMOS that the video out is selected to go to the correct place. I can't believe you had a video card though, and still opted to get one with the video onboard, those are usually the shittiest boards imho. Too many extra ways for the signal to get fucked, you don't find onboard video on better mobos for a reason =)

 

'in your CMOS' means the same as 'in your BIOS'. The two terms are often used interchangeably for doing the exact same thing.

In reality, BIOS contains the instructions that tells the PC how to operate. These instructions can not be changed by the user [except for BIOS flashing]. The CMOS is a tiny memory module contains the variable settings which we set, such as primary video driver, boot load order, etc.

So when we say to "enter the BIOS" or "change the BIOS settings" we should more properly be saying "CMOS". Almost everyone just uses the term BIOS to refer to the whole thing anyway.

 

Yeah, for some reason I missed the "at all" part. Swap out the video cable, see if that fixes it, if not, I'd take the mobo out of the case, set it on a piece of cardboard, hook everything up, and then try to boot. You might have something shorting out in the new case since it worked before you moved it.

 

Did you manage to sort this one out, Xiph?

 

Sounds like a dead graphic card or a grounding issue. Remount your motherboard and retest.

Now, if you're still getting no video, even through the onboard video, I suggest you reset the BIOS (or CMOS, by unplugging the computer, taking out the battery, wait for 2 minutes, then put back battery and replug everything).

That should fix the onboard video, at least. Otherwise the mobo is shot.