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Asus M4A785-M no VGA output

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New Member
Dec 4, 2011
Satan's Colon, US
I have an old Asus mobo that worked just fine when I retired it. Last night I decided to see if I had enough old parts to slap together a functioning back up rig. When I tried this mobo everything seems to work, CPU fan spins up and cycles from high to a lower speed, light comes on, HDD sounds like it's doing something. I got no signal from the onboard graphics chip. I tried all three ports (VGA, DVI, HDMI) with different cables and three known working monitors. Next, figuring the old Radeon HD 4200 gave up, I tried two different graphics cards and got the same results. Bot cards work, all monitors I tried work, and all the cabling I tried works. I also tried two CPUs, a Phenom X4 9850 and a Phenom II 980 BE, with every iteration listed. Same results. I tested both CPUs in another mobo and both worked with no issues. Same with three different RAM sticks.

I cleared CMOS and found no problems with a couple hundred visual inspections. If there was a PCIe failure, would that affect the onboard graphics? I had OC'd the PCIe on the board previously, but never ran it over 110% and never touched the voltage. It was only for a few minutes (leading to the discovery that OCing your PCI will break your Windows faster than a myopic Berkeley with a box of rocks). It ran fine for over a year after that. About 5 years ago I had to RMA the original board and got a brand new one back from Asus, so its service life was only around 3 years. I'm all out of skills and experience on this one, so I'm open to suggestions.
The motherboard has an onboard Radeon HD 4200 GPU. I also tried a R5 240 and a RX 480, both of which are working cards.
Showing my age I guess. I didn't know they integrated pgu with the *board*. I had thought that was an on-cpu feature that was only available with specific cpus.

Best I can say is give it a bath in isopropyl and a good gust of wind from the compressor. Whatever happens I am curious of the results. Good luck
How reliable is the Power Supply you're using?

Do you have a power on light on the board? What color?
The light on the board is green, and lights. It's an old low end PSU, but it powered another mobo with both chips and all the peripherals, except case fans. Because it was built on the living room floor. I checked the PSU with a multimeter. Seems odd that it won't output a VGA signal even with a discrete card.

edit: I'm not getting the lights on the keyboard either when it powers up. That's probably not a good sign.
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You've mentioned you have cleared the CMOS. Aside from triple checking all your connections (the CPU 12v gets me all the time) and re-seating the ram/CPU I'd say it's probably dead. :(

These are the posts when I wish RGone was still here. Right up his alley. Maybe PM Scotty if you don't get any other suggestions. He's pretty handy with these older boards too.
I've gone over every plug and connection several time, unfortunately. The cheesy little CPU cooler I put on it to test the board isn't getting warm at all. I don't know how it died sitting in a closet, but it seems to have gone peacefully in its sleep. LOL I may try the oven trick if someone doesn't come up with an "Ah ha!" moment. The graphics card gets warm, it just doesn't output a signal.

I just unplugged it and pulled the cooler off. The chip is colder than a mother in law's heart. :(
Same chip, same cooler, isn't getting warm in another mobo either. Then again, the fan on the cooler is turning 4500 RPM so I'm surprised it isn't flying around the room. I guess I have to get a new motherboard. I should probably get on that soon, as AM3 boards may be a little scarce. :D
It's BIOS 1101, the latest. I did notice it wasn't on the list, but the 9850 I tried was running on that board previously, and works fine in another board. I'm not sure why the 980 isn't on the list. Every other P II X4 and P II X6 is. I'm starting to suspect the socket. I have to be very careful removing the cooler or the chip just pops right out. I'm going to look for an old speaker and try to get some beep codes. I should have thought of that sooner.
I would suspect the socket as well because we see the same symptoms in Intel boards with bent socket pins or on AMD boards where a CPU pin is bent or broken off.
Yeah. The pins are all good. What bugs me is it came out of a working rig. After the RMA replacement the board was only a couple years old. I don't know if there would be any clues under the backplate or not. It's a major disappointment. I'm using a complete piece of crap ECS mobo at the moment in that rig. I'm trying to figure out what trouble shooting I can pull off.
I'm not. First off I'm getting the 24x magnifier out and looking at the socket to see if I can spot anything. Not much faith in that either, but the board has sentimental value as well as being perfect for my retro build/backup rig.
Gave it a thorough cleaning with isopropyl, hooked up a speaker and nada. No beeps. I took a junk Socket 940 socket apart to see what's in there and how to get to it. If I can get in the socket without breaking anything I'll have a look and see what's up, if anything, in there. If I don't spot anything obvious in there like a dead cat I'll reflow the solder on the socket pins from the back of the board. If I were a doctor I'd be the guy at the funeral home doing CPR. LOL. I'll reflow every solder joint on the board this winter. I need a hobby anyway. :clap:

edit: Correction, it doesn't look like the socket pins can be reflowed from the back side. Well, phooey.
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It's not the socket.

Onboard graphics failed.
The problem with that board and a couple others just like it is, The bios defaults to onboard graphics when cleared, and a discrete card is not identified unless you turn off the onboard graphics, which you can't do because you have no way to see the bios.
I have a couple boards just like it here, in the same situation.
Most boards now will output on the discrete card so you can at least see the bios to turn off the onboard.
This particular board will not. There are a couple others that are the same way. Biostar has one, and Asrock or MSI I think is the other. All were from the same era.
It was a sh1tty design.

Anyhow, throw that board away.
I rigged up a speaker and didn't even get a beep. So, yeah it's a goner. Getting to be a pain to find a half decent AM3 board for reasonable money anymore. This https://www.amazon.com/M5A78L-M-Plu...566&sr=8-1&keywords=Asus+-+M5A78L-M+PLUS/USB3 looks like basically the same board with lousier on board graphics and a cheesier power section. What's your opinion of this board? https://www.outletpc.com/hf1999.html# It looks like it might have a decent power section on it. My issue is I went and bought a 980 BE because I thought I had a mobo to play with it on.
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790-890 chipset boards are what you want but, so does everybody else. They're $75+ when you see them.