4870 no signal to monitor

[yannis18]

Hi everyone,

I am experiencing a very disturbing issue with my newly installed ATI 4870 and my Windows 7 RC (7100).

Prior to installing this card I had the following setup, which worked flawlessly.
nvidia 8800gt
intel p35 chipset in the motherboard
Samsung a656 40" LCD connected via a DVI to vga connector.

When I got my 4870, I uninstalled the nvidia drivers,rebooted, installed the latest (9.5) ati drivers and rebooted.

Then, I got a no signal in the monitor at the windows login screen.

Mind you, that when I (dual) boot in Vista, using the 9.4 drivers, everything is fine.

Things that I tried:

1. Creating a new monitor.inf file (located at the windows folder) using info from a post in this forum.

- This should not make a difference, since I was using the same monitor.inf file in the same windows 7 installation, whitout any issues before I installed the 4870.
​

2. Changing the ATI .inf file to include only one resolution for the r7x cards 19 20 10 80 00 00 00 60

- I think it sould be a refresh rate issue, since the vga port of the TV supports many resolutions, including 1600x1200 etc.
- It could also be an unsupported resolution, if the ATi driver cannot detect the monitor correctly.
​

3. Installing the windows 7 default ATI driver.

Things that I noticed:

1. I can login only in safe mode.

2. Low res mode (640x480) gets me to the login in screen, but as soon as I input my passowrd, I get no signal.

3. Changing DVI ports in the 4870 (it has 2)

Does anyone have any ideas?

 

[torrentg]

Login to safe mode and change the refresh rate. try to set it to 60 first. Boot normal and test. Try 75 next if that is unsuccessful.

 

[yannis18]

Thanks, but..

Safe mode displays a generic monitor in the display panel.
It does not allow for any change other than the resolution.
One thing that I failed to tell is that, when in safe mode, the max resolution is something like 1944x1400 which obviously is unsupported by my TV.
Maybe this is where the problem lies, windows telling the monitor to work at that resolution, during normal boot.

 

[torrentg]

Eh...damn, too bad. Have you tried installing the Catalyst driver in safe mode? Just ideas I think of...

 

[yannis18]

Thanks,

already did that.


It seems that the problem is far larger, just check the ATI forums and beware.

AMD Game Forums - HD 4870 Vista black screen / no monitor signal after install

 

[yannis18]

Update:
I managed to "fix" the issue by connecting my TV via a DVI to HDMI connection.
I think the issue must have happened because the TV is operating at 59,5 hz Refresh rate when via VGA and 60hz via HDMI.
Anyway, the TV was properly identified by windows, i set the refresh rate to 59hz and both connections work now.