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ATI Radeon HD 4850 Issues

Last response: in Graphics & Displays
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June 17, 2011 9:11:24 PM

So I've been using this card for about 18 months now. Recently I've been playing slightly more demanding games, and my card's been running very hot (~105C). A few times my PC shut itself down while playing, perhaps some failsafe to stop the card frying itself. After this, rebooting my PC causes the fan to instantly run at 100% speed for a while when it normally starts low.

Anyway I've just opened my PC up and given it a good dust, reconnected everything at gone to fire it back up again, and I'm receiving no signal through the card. Everything else if fine, I'm typing on here now with my monitor plugged into the VGA port on the motherboard. When I turn it on, 2 red LEDs turn on on the back of the card for ~ 2 seconds and then go out again, just as the fan kicks in and spins at full speed. The LEDs remain turned off but the fan doesn't stop, even when the power cable to the GPU is unplugged. I've searched issues regarding red LEDs, and all I find is scenarios where the lights remain on or continuously flash.

TLDR: No signal through GPU, on start 2 red LEDs flash for ~ 2 seconds followed by the fan continuously spinning at 100%.

More about : ati radeon 4850 issues

June 17, 2011 9:34:15 PM

The most common cause would be the power supply is damaged on it's 12v rail.

The higher the temp, the higher the current draw with most cards.

Try the card with another power supply, If the one you are trying it on is under 400 watts, its ok to run in 2d mode, but don't play any games until you get a better one. Do you have something like a old 250 watt kicking around?
try it and see if it runs in 2d mode.

Maybe in the bios if a card shuts down it changes to any available vga card and it enabled the onboard video. In the bios it should be set to "primary video" "pcie slot 1" . If the onboard video is enabled and working, then it wont try to run the card in the pcie slot.
June 17, 2011 9:43:54 PM

My PSU is 450W. I did open it up to dust it since it was pretty dusty in there... could it have been something I did? It just seems odd that it was working before I dusted it.
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June 17, 2011 10:24:25 PM

Ok from what I've seen the red lights are standard. I've gone into BIOS and set pci-e to default with no effect. I still don't know why the fan constantly spins (regardless whether the 6 pin cable is plugged in or not. Despite heat issues I think whatever's gone wrong happened whilst dusting it. Anyone else have any information ;-)
June 17, 2011 11:00:54 PM

My guess is it's the power supply. Try the card in another system in 2d mode, or try getting a loner power supply to try. The card will not work without the power cables plugged in.

June 17, 2011 11:45:18 PM

May I ask how I can set it to 2d mode?

Also I find it funny that when I normally start my PC, the fan spins at full power for 2 seconds and then goes low as the system boots. Now, it's quiet for 2 seconds, and then goes full power endlessly.

Anyway thanks for the input guys, though I'm still wondering what actually triggered this problem... Whether it was a coincidence that I happened to clean my PC just as it failed or I did something stupid :/ 
June 18, 2011 12:13:40 AM

The card runs in 2d mode when it boots up and runs normal windows tasks like internet surfing. What i meant is if you try something like a 250 watt to 400 watt power supply, or don't want to risk frying a borrowed power supply, don't play any games. The gpu clocks go up when playing games or any 3d tasks. That is when you need a larger power supply.

You should have something like a antec 600 watt or corsair 600 watt
a 450 watt or generic 500 watt often won't put out enough for that card when running games.

It is possible the card died, i hope not, but if you want a new card that is a bit faster and uses less power, get either the 5770 or 6770, 6790. The 6850 is ok too.
June 18, 2011 12:17:20 AM

You need to do some trouble shooting first, and find out if it's the power supply, or card.
Try the card in another system and see if it displays when first starting.
DON'T LET IT BOOT WINDOWS OR WINDOWS WILL CHANGE THE VIDEO DRIVERS
Just see if you can get the card to work during the bios post.
June 18, 2011 12:29:12 AM

NO!!! don't buy anything until you troubleshoot first. There is nothing wrong with a hd-4850 card, they usually work fine.

If it's the card and the 450 watt is still working well, then the lower wattage 6790 will run fine on it if the 4850 was.

Plus without troubleshooting you end up keeping junk around that you think might still work.
June 18, 2011 9:25:22 AM

Unfortunately no one who lives near me has a pc big/new enough to test my card, and I have no old PSUs lying around. Perhaps it's time to build that PC I was thinking of doing over summer.
June 18, 2011 5:57:28 PM

Is there anything else I can try in the meantime? It'll be a while before I can get access to another PC to troubleshoot. I've tried clearing bios and reinstalling drivers with no luck. Fan on GPU still runs at full speed, but my PC just can't detect that it's there.
!