# [SOLVED] HD 6770 Screen goes black "no signal input"



## thrombox (Dec 12, 2009)

Spec:

Dell Optiplex 755 SFF
A22 Bios
Intel E8600 3.33Ghz CPU
Chipset Intel Q35
2Gb Ram
320Gb HD
1GB HD6770 Radeon
Windows XP 32 Bit Home.

Succesfully installed a new HD 6770 Sapphire low profile card, it works very well in heavy gaming etc.

Initially I was having problems with the screen going black and "no signal input" coming up, this was random and could happen in 15 seconds or after 30 minutes.

Anyway went to the BIOS and changed the graphics controller but I only have two options "Auto" and "Onboard/Card" (the onboard/card one says it will use the PCI-e slot to override the IGP". I switched it back to "Auto" as it was on "Onboard/Card".

So anyway now the problem seems to be mostly cured, but this time if I leave the computer alone for longer periods without use I again get the "no signal input" no amount of reconnecting helps it and I have to restart.

Does anyone know how I can solve this? It appears I am not able to disable the IGP and the HD6770 manual does say I should do this.

I also reloaded the HD 6770 drivers again just in case. I also appear to have two monitors in "display" in the control panel I seem to be unable to remove the 2nd unused monitor.


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## Tyree (May 10, 2009)

*Re: HD 6770 Screen goes black "no signal input"*

If you're using the 305W OEM PSU that came with the Dell, you should remove the 6670 GPU immediately. 
Replace the PSU is replaced with a good quality 450W minimum unit.
SeaSonic-XFX-Antec HCG are top quality.


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## T_Rex (Oct 21, 2012)

*Re: HD 6770 Screen goes black "no signal input"*

Update op? Did you trash the dell power supply?


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*



Tyree said:


> If you're using the 305W OEM PSU that came with the Dell, you should remove the 6670 GPU immediately.
> Replace the PSU is replaced with a good quality 450W minimum unit.
> SeaSonic-XFX-Antec HCG are top quality.


This is totally incorrect.

I triple and quadruple checked this.

Plenty of people use the low power low profile Sapphire HD 6670 for years on the 755 SFF with no problems whatsoever the PSU is more powerful than Dell marked it, and it is the 2nd best graphics card you can use for a 755 SFF optiplex, I researched this ad nauseam before buying.. The PSU cannot be replaced on the SFF model there is not enough space to my knowledge.

This is from reading several threads on the official Dell forum itself, please take it from me and drop that angle of thinking.

I can play games at high graphics settings for hours on end with no black screen or any problems. It is *only* when I leave the computer idling for something like 30 minutes or more do I get the "no signal input", it has to do with the IGP taking over which I cannot disable from BIOS and which is a requirement for the HD6770.


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## greenbrucelee (Apr 24, 2007)

*Re: HD 6770 Screen goes black "no signal input"*

I wouldn't use a 305w psu with that card and I used to test power supplies and cards for my job.

AMD even say you should be using a 450w.

Go into your BIOS if you can but you probably cant because its a dell and see what the voltages say or use CPUID hardware monitor but BIOS is more accurate.

When manufacturers state specs they don't just make them up, they usually see what the TDP is and then add to it to allow for electricity fluctuations, brownouts and other factors.


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## T_Rex (Oct 21, 2012)

*Re: HD 6770 Screen goes black "no signal input"*

Throm that's likely a power setting handling issue between your OS and your box as you have already discovered, and you can possibly mitigate it by using the device manager if your bios keeps giving you a hard time. Boot up with IGP, and then when in windows disable it in the Dev_MGR. Upgrading to windows 7 might help but I realize you may not want to do that with that box given your specifications.


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*



greenbrucelee said:


> I wouldn't use a 305w psu with that card and I used to test power supplies and cards for my job.
> 
> AMD even say you should be using a 450w.
> 
> ...


What upgrades for the Dell Optiplex 755 Tower(mini tower)? - Desktop Video Forum - Desktop - Dell Community

Look at the official recommendation by the Dell customer support (i.e. "Single Slot Versions of GDDR5 Radeon HD6670 1GIG cards are what I recommend for the 755 Tower with 305W power supply."). 

There are threads after threads recommending this. AMD says 400W, a massive overestimate to cover their liability. There has been a lot of coverage of the 755 SFFs with the HD6770, no problems with it whatsoever and it is the official recommended upgrade by *DELL* :banghead:

Again please take it from me and drop that angle.

Lets get back on subject which is "no signal input" at idle and turning the IGP off which I can't do in the BIOS.


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## greenbrucelee (Apr 24, 2007)

*Re: HD 6770 Screen goes black "no signal input"*

Who to believe dell who dont have anything to do with the manufacturiung of the card or AMD who do manufacturer the card.mmmmmm

Dells support is childish at best the majority of the time, this is why I would never use one or have my work use any.

Turn off your power management in windows if you can and see if it helps but I still maintain running that card on a 305w psu is asking for trouble. You can get lower profile power supplies.


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*



> Throm that's likely a power setting handling issue between your OS and your box as you have already discovered, and you can possibly mitigate it by using the device manager if your bios keeps giving you a hard time. Boot up with IGP, and then when in windows disable it in the Dev_MGR. Upgrading to windows 7 might help but I realize you may not want to do that with that box given your specifications.


Ah ok I will try this thank you. (and no I'll keep Win Xp! :smile: )




> Who to believe dell who dont have anything to do with the manufacturiung of the card or AMD who do manufacturer the card.mmmmmm
> 
> Dells support is childish at best the majority of the time, this is why I would never use one or have my work use any.


Yes but there is user review after review of the HD6670 with the 755 SFF, it works perfectly.

Also plenty of tests on the Wattage of the LP Sapphire HD6670, they all concur, nothing like 400W PSU needed, you can even get away with 250w or less in some instances.


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## T_Rex (Oct 21, 2012)

*Re: HD 6770 Screen goes black "no signal input"*

I think the above have the 6670 confused with the 6770 maybe.


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## greenbrucelee (Apr 24, 2007)

*Re: HD 6770 Screen goes black "no signal input"*

how many of those "reviewers" have come back and said my comp doesn't work anymore because I screwed it by underpowering it? probably none because people who do things like that never come back and admit they have screwed up.

But lets stop arguing it's upto you what you want to do it's your system, your money.

Just a friendly piece of advice and don't take offence but there is a reason why people like me never have any issues with their computers and reason why others do.


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*



ChronoGeek said:


> I think the above have the 6670 confused with the 6770 maybe.


OOPS my bad.. Yes 6670 not 6770, sorry typo error in the title, apologies everyone.



> But lets stop arguing it's upto you what you want to do it's your system, your money.
> 
> Just a friendly piece of advice and don't take offence but there is a reason why people like me never have any issues with their computers and reason why others do.


I agree, but I have researched this exhaustively and did want to get back to the actual subject the IGP!


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## greenbrucelee (Apr 24, 2007)

*Re: HD 6770 Screen goes black "no signal input"*



ChronoGeek said:


> I think the above have the 6670 confused with the 6770 maybe.


This is what I am looking at Power supply requirements for ati radeon 6670 - Graphics Cards - Graphics & Displays it says 400w


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*



greenbrucelee said:


> This is what I am looking at AMD Radeon™ HD 6770 Graphics


Yes my bad in the title, typo error it is in fact the 6670, and that is yet another thread recommending the 6670 for lower power supply.


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## greenbrucelee (Apr 24, 2007)

*Re: HD 6770 Screen goes black "no signal input"*



thrombox said:


> Yes my bad in the title, typo error it is in fact the 6670.


yeah I realised that 400w is reccomended.


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## T_Rex (Oct 21, 2012)

*Re: HD 6770 Screen goes black "no signal input"*

Well the 6670 especially low profile , given it's economical circuitry should be fine. The issue is likely motherboard itself and the particular GPU you have interacting with an older operating system. Check your settings in the control panel make sure you have hibernation enabled, and if that doesn't work try the Dev_MGR (if you don't need to use your IGP).


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## Tyree (May 10, 2009)

*Re: HD 6770 Screen goes black "no signal input"*



thrombox said:


> This is totally incorrect.
> 
> I triple and quadruple checked this.


Nothing incorrect about it.
Did you check with the chipset manufacturer?

AMD Radeon™ HD 6670 Graphics


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*



Tyree said:


> Nothing incorrect about it.
> Did you check with the chipset manufacturer?
> 
> AMD Radeon™ HD 6670 Graphics


Like I have said before again and again in this instance the manufacture states this to cover themselves for warranty, there is no additional power connector on the LP HD6670 card it is a low power card, enough people have tested the voltage of these cards on systems such as mine, quoting someone who has tested this card:



> Even a 250 Watt power supply unit like the Seasonic TFX SS-250TFX and the SFX SS-250SFD will work. It's not the power supply's total wattage that determines whether or not the power supply is capable of properly powering the system. Always look at the combined +12 Volt continuous current rating of the power supply.


Back to the issue at hand..



> Throm that's likely a power setting handling issue between your OS and your box as you have already discovered, and you can possibly mitigate it by using the device manager if your bios keeps giving you a hard time. Boot up with IGP, and then when in windows disable it in the Dev_MGR.


I tried this but the trouble is I get a black screen and no signal input if I try and connect from the IGP to the monitor.

I also identified one of the things that was causing it, in power options turn off monitor was set to 20 minutes, it seems this caused the black screen and then "no signal input".

Trouble is this no signal input still does occur on occasion when turning on the computer, but once windows is loaded its gone. 

Even in this state I still consider it a problem as the core issue has not been dealt with, I wouldn't mind the monitor actually being able to turn off for example after 20 minutes.

The guy bloc97 in this thread knew exactly what was going on, but I cannot get in touch with him:

No input signal - HD6670 card problem [Solved] - Radeon - Graphics & Displays


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*

Can no one really help me?

I've now deduced this is 100% a Windows/Software issue, but I still have no idea how I can stop it.

Here's what I've done/what happens.

-If I set x minutes to turn the screen off in power options, once the screen turns off I then get the "no signal input", although I still get skype calls etc. So I've set turn screen off to 'never'.

-I reinstalled Windows XP and the drivers, same problem.

-Trying to use the IGP while the graphics card is installed produces a black screen with no signal input, obviously the IGP is disabled by the software.

-Removed the graphics card and loaded up with the IGP, checked device manager there are no hidden drivers etc. that I can uninstall.

-When I have switched the computer off for a while and turn it on for the first time I am guaranteed a "no signal input" black screen when windows has just loaded. 

I thought this was card related but when I removed the graphics card and used the IGP, I also get this black screen for a second or two when Windows has just loaded. Clearly the monitor powers off for a second or two, in the case when using the HD6670 it results in getting the 'no signal input' screen.

Oddly this only occurs the first time I load up the computer after a period of use.

-Occasionally when turning off the computer I get this 'no signal input' screen and the computer doesn't turn off, haven't been able to ascertain the cause of this.

It is clear to me it must be due to the fact there is no permanent way to disable the IGP in the BIOS so whenever the monitor turns off for even a moment, the system switches over to the IGP, thus giving me the 'no signal input' screen.

P.S. I am able to play games on max settings for 8 hours straight, stable with no problems whatsoever.


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## greenbrucelee (Apr 24, 2007)

*Re: HD 6770 Screen goes black "no signal input"*

is your clock in the BIOS correct?

If not replace the cmos battery.


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*

Clock in BIOS is correct.

Could it be that the graphics card is faulty? It works fine in games?

It was brand new, can't see that being the problem.


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## greenbrucelee (Apr 24, 2007)

*Re: HD 6770 Screen goes black "no signal input"*

I still say your underpowered which is why the GPU would be faulty. Borrow a quality psu which is of sufficient wattage and see what happens.


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*

Well you guys maybe right to an extent.

Further research shows that the HD6670 is fine with the 305W PSU Dell Optiplex 755 I have the 275W PSU, and an old PSU at that.

I will test on a better PSU today and let you know.


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## Tyree (May 10, 2009)

*Re: HD 6770 Screen goes black "no signal input"*

I don't know where you have been researching but you're getting incorrect information about the power requirements for a 6670 GPU.
The chipset manufacturer, AMD, recommends a minimum 450W PSU (clik on "Support" tab): AMD Radeon™ HD 6770 Graphics 

And Sapphire, the maker of your particular 6670, also recommends 450W minimum (Clik on "System Requirements") tab: SAPPHIRE HD 6770 1GB GDDR5

Insufficient power may or may not be the cause of your immediate problem but using a low quality underpowered PSU will, without doubt, have negative effects on the GPU as well as other components.


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## thrombox (Dec 12, 2009)

*Re: HD 6770 Screen goes black "no signal input"*



Tyree said:


> I don't know where you have been researching but you're getting incorrect information about the power requirements for a 6670 GPU.
> The chipset manufacturer, AMD, recommends a minimum 450W PSU (clik on "Support" tab): AMD Radeon™ HD 6770 Graphics
> 
> And Sapphire, the maker of your particular 6670, also recommends 450W minimum (Clik on "System Requirements") tab: SAPPHIRE HD 6770 1GB GDDR5.


Yes but like I said they do this to cover themselves, this is way above the actual requirements.

You are right however that 275W is slightly underpowered, I am now 100% sure this is my problem, people do have good results with the 305W Dell Optiplex however, although it is still cutting it slim.

Apologies for my obstinacy, feel free to close this thread I consider it solved and am removing the card.


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## Tyree (May 10, 2009)

*Re: HD 6770 Screen goes black "no signal input"*



thrombox said:


> Yes but like I said they do this to cover themselves, this is way above the actual requirements.


More misinformation. ^

But, your money - your choice.


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## thrombox (Dec 12, 2009)

*Re: [SOLVED] HD 6770 Screen goes black &quot;no signal input&quot;*



> More misinformation. ^
> 
> But, your money - your choice.


No it's not misinformation. The wattage and power usage of such cards has been tested extensively and is ok on a 305W system, mine is 275W.

I just solved my problem in the end by downloading the latest drivers from the Sapphire site and uninstalling those from the Sapphire CD driver. No more signal input, running games at max settings.

But I am still going to buy a system with a bigger PSU to be on the safe side.


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## greenbrucelee (Apr 24, 2007)

*Re: [SOLVED] HD 6770 Screen goes black &quot;no signal input&quot;*

dont buy a system build one, companies that build systems for you generally use low quality parts and charge OTT prices for it and when you build you can ensure you put quality parts in it.

When you say its been extensively tested and is ok. How long were these systems tested? 1 day (means nothing) 1 week (means nothing) 6 months (your getting there) 1 year I would say yeah it's ok.

I have seen many systems run ok on underpowered systems for a month then they die, when you see reviews on sites that you buy stuff from and see people saying I'm running this on a 250w and I have no problems you never ever see them come back and say I have completely screwed my system up because I have under powered it.


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## thrombox (Dec 12, 2009)

*Re: [SOLVED] HD 6770 Screen goes black &quot;no signal input&quot;*



> hen you say its been extensively tested and is ok. How long were these systems tested? 1 day (means nothing) 1 week (means nothing) 6 months (your getting there) 1 year I would say yeah it's ok.


People with a dual core CPU and a 305W Dell power supply have been reported good with an HD6670 for long periods, less than that it's like you say could be a month or a few weeks, I've got a 275W so too much to risk.

Honestly can't remember the sites I went on comparing the Dell 305W etc. but they can be found with a google search.



> dont buy a system build one, companies that build systems for you generally use low quality parts and charge OTT prices for it and when you build you can ensure you put quality parts in it.


Thanks, I just bought an HP xw4600 with a 475 Watt PSU so should be more than adequate.


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## Tyree (May 10, 2009)

*Re: [SOLVED] HD 6770 Screen goes black &quot;no signal input&quot;*



thrombox said:


> Thanks, I just bought an HP xw4600 with a 475 Watt PSU so should be more than adequate.


Best of luck.


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