# [SOLVED] Screen flickering for AMD HD 7770 / Monitor not recognized by OS



## darth_sithus (Aug 13, 2012)

My friend recently purchased a Gigabyte AMD HD 7770 graphics card. 

Firstly the games he played would freeze for a few seconds and then the notification would show in AMD CCC that device driver has failed and recovered.
This was solved by updating the drivers to latest stable 12.6 catalyst drivers.

But now a new problem has started. Whenever he starts any game, it loads to menu screen without any problems but in game, the screen starts to flicker like an old CRT with a very low refresh rate.
But there is no flickering in menu screen and desktop. But on closer inspection, we found that even in desktop there is a flickering but not as noticeable as in games.

In display settings, we found that monitor was not getting recognised by windows 7 and it was showing as generic non-pnp monitor. The card had an HDMI port so we connected it to the TV where there were no issues and no flickering.
The monitor is a Viewsonic 18.5 inch LCD with a VGA port. The graphics card does not have a VGA port hence he uses a DVI-I to VGA adapter.

For your reference here is a list of troubleshooting steps followed by me based on what I could search on google(None worked so far):


Rolled back to previous driver(12.1). 
Performed a clean install of driver using driversweeper. So far I have tried with catalyst drivers: 12.1, 12.3, 12.6 & 12.7 Beta
Checked the DVI port and the DVI connector(No noticeable physical damage)
Tried to manually set referesh rate to 75Hz from monitor.
Tried the DVI adapter on my PC(It works on my pc)
Tried to underclock the graphics card to 1000Mhz


His configuration:
Processor: Intel i5 3450
Mobo: Asus b75 MLE (Bios ver. 0410)
Ram: 4GB DDR3
Gfx: AMD HD 7770 1.1Ghz clock
PSU: corsair cx430
Monitor: Viewsonic VA series 18.5 inch max res 1366x768 @ 75Hz via dvi-i/ TV: Panasonic Vierra FHDTV via HDMI 1.4
Display Driver Version: Catalyst 12.6
OS: Windows 7 Professional 64 Bit


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## avinandan012 (Aug 13, 2012)

try the monitor with another PC if the problem still persists send it to RMA


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## aloodum (Aug 13, 2012)

Is'nt there an option in Catalyst under display options to use composite signal? Try that and let us know.


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## darth_sithus (Aug 13, 2012)

avinandan012 said:


> try the monitor with another PC if the problem still persists send it to RMA



Tried that. Montior works fine on another PC.




aloodum said:


> Is'nt there an option in Catalyst under display options to use composite signal? Try that and let us know.



Where is that option? I can only find Detect Display and Rotate display options.


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## d6bmg (Aug 14, 2012)

Problem is due to the VGA port you are using. If the monitor have a DVI port, but a DVI cable and use it. Your problem will be solved.
Possible reason: Conversion error from Digital to analog signal.


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## RCuber (Aug 14, 2012)

offtopic.. I think this is the first time after many years that I am seeing a member post a query after doing proper initial troubleshooting  

ontopic. Yes even I feel its the VGA conversion which is giving the issue. check with a different cable/VGA converter. @d6bmg.. his monitor doesn't have a DVI port.


EDIT:
@OP can you check by connecting the GFX and monitor to your PC.


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## darth_sithus (Aug 14, 2012)

d6bmg said:


> Problem is due to the VGA port you are using. If the monitor have a DVI port, but a DVI cable and use it. Your problem will be solved.
> Possible reason: Conversion error from Digital to analog signal.





RCuber said:


> offtopic.. I think this is the first time after many years that I am seeing a member post a query after doing proper initial troubleshooting
> 
> ontopic. Yes even I feel its the VGA conversion which is giving the issue. check with a different cable/VGA converter. @d6bmg.. his monitor doesn't have a DVI port.
> 
> ...




You may be correct. The card has DVI-I port but there is a square sinewave marking besides the port. Does this mean it only processes digital signal? But there were no issues previously when we first installed the card.  I am at work right now. I will post some screenshots of ATI CCC and a pic of the port later in the evening for better understanding.

Either the display port has gone bad or the monitor just doesn't accept proper signals from the card.


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## CyberKID (Aug 14, 2012)

Have you checked the screen's refresh rate. There are times when screen flicker occurs due to either high or low refresh rates also. Though, chances of this being the cause are bleak, but, you can do a check for this too.


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## Tech_Edge (Aug 14, 2012)

problem is your vga to dvi converter change the converter


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## d6bmg (Aug 15, 2012)

darth_sithus said:


> You may be correct. The card has DVI-I port but there is a square sinewave marking besides the port. Does this mean it only processes digital signal? But there were no issues previously when we first installed the card.  I am at work right now. I will post some screenshots of ATI CCC and a pic of the port later in the evening for better understanding.
> 
> Either the display port has gone bad or the monitor just doesn't accept proper signals from the card.



Well,I've posted this from my personal experience. Whenever I onnect any of my monitors with VGA cable and then try to change the mode of operation from the monitor, flickering occurs.
As youur monitor donn't even have DVI port, I think that monitor isn't made for digital signal and that's why flickering occurs.


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## ico (Aug 15, 2012)

darth_sithus said:


> You may be correct. The card has DVI-I port but there is a square sinewave marking besides the port. *Does this mean it only processes digital signal?* But there were no issues previously when we first installed the card.  I am at work right now. I will post some screenshots of ATI CCC and a pic of the port later in the evening for better understanding.
> 
> Either the display port has gone bad or the monitor just doesn't accept proper signals from the card.



Like Charan and Tech_Edge said, the problem is with your DVI-I to VGA adapter. *i.imgur.com/HT4uM.png

Regarding the bold part, what a DVI-I to VGA adapter does is - it discards the digital signal, converts the signal from those 4 square analog pins to D-Sub/VGA analog. Then you use your VGA cable.

What you could do is, try buying a DVI-I to VGA cable. I am using one myself and it also discards the need of the adapter. Should cost Rs. 150 and it will do the job for you.



d6bmg said:


> Problem is due to the VGA port you are using. If the monitor have a DVI port, but a DVI cable and use it. Your problem will be solved.
> Possible reason: *Conversion error from Digital to analog signal.*


Conversion from Digital to Analog _never_ happens in a DVI-I to VGA adapter. (the ones which we get with our graphic cards)

The 'conversion' problem is there but it is in analog-to-analog itself.

The four square pins which you see on the left carry the analog signal in a DVI-I connector.

*i.imgur.com/sb1WW.png


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## darth_sithus (Aug 15, 2012)

SOLVED!! PSU was the issue!

It was because the Card was connected to 4-pin Molex connectors instead of normal 6-pin pci connectors. Finally RMA'ed the PSU and now it is working fine on 12.6 Drivers


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## coderunknown (Aug 15, 2012)

low power was causing graphics problem.

problem solved. closing thread.


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