I have an electrohome ECP4101 projetor.

All running pretty well BUT I cannot get any detail in the dark parts of the image without turning up the brightness and so destroying the black level. (blacks become grey, but details in dark areas are revealed)

I am using the RGBVH input (although true of video input and with different sources)

Any ideas?

Cheers,

Ian:)

Gamma correction. Use an HTPC with FFDShow and Zoom Player pro. Check "levels" on ffdshow and bring the middle tab to highlight "curve". Click and drag the bottom left point to the right until it turns to the number 16.0 on the top right. Then click custom points on the bottom area and curve outward towards the left without curving the upper end. The lower end controls dark areas. Just play aorund with dark scenes playing. First calibrate the brightness until you hit true black on a fade to black with a dvds source.

I'll try to post an image example later on so you will better understand. It makes a world of difference though.

What sources are you using? There are other ways to get gamma correction, including many scalers, or external boxes like Kim's RTC2200, etc.

Kal

Advice for Gamma Correction using PC great, thank you.

I am using a fairly basic PC as a source, running Windows 98SE, as that's what I have available! I have fitted a NVIDIA 4MX 440 SE graphics card.

Output is absolutely fine on a PC monitor. So....

I would be interested to know if I should be revisiting some of the projector's calibration before I resort to tweaking the signal. The video null controls on the video control module, or the cathode DC level on the video output module?? I just don't know how good the image should be, but the blacks are very 'crushed' at the moment without greatly increased brightness resulting in grey blacks.

Quite competent to make adjustments - have a 'scope and a multimeter and good elelectronics knowledge - even have the extender card but need a little guidance.

Any more ideas please?:confused:

Video null controls are pretty easy but might be worth a try tweaking. Put up the convergence grid and then turn off each tube with the video kill switches on the G2 board... if you can see a negative of the convergence grid then something is up.

Are you sure your G2 is setup right... I haven't played with my ECP in a while so it might be worth checking that. What are your contrast level set to?

Make sure you are doing all this work in a pitch black room eh... light coming in can really wash out any black detail obviously. Tweaking gamme is a definit on the ECP atleast I found so give that a shot its quite simple to undo if you mess it up...

Also try to get a grey test patten from black to white with bars so you can see where your loosing your black that will make setting game easier.

good luck

I think null and G2 controls are reasonably set up, as I carefully followed instructions from the Service Seminar.

Contrast seems good around 4 or 5 but can be as low as 3 when brightness up at 7+ to reveal detail in blacks.

I am viewing in near dead blackout.

When you say go ahead and adjust the gamma, do you mean actually as part of the ECP (in which case I do not know where I should be tweaking)? Or do you mean give it a go externally with the source material?

Thanks for help and advice.

Ian:)

I think you've got your contrast and brightness levels backwards.

I always had my contrast near 6 or 7 and brightness lower at like 5

But I pushed my little projector pretty hard, although still no visible burn...


There is no gamma correction on the ECP, I was suggesting you tweak it on your PC atleast if you mess it up you can quite easily restore the dafaults.

I would suggest you increase your contrast though may make a bigger difference then you think. Of course contrast and brightness are relative to all your other analog settings so you can't directly compare one set to another.

Seen as though you have a scope and know how to use it, you may wish to check the RGB voltage at the projectors input. E-homes like a hotter input voltage than most vid cards produce. How long is your RGBHV cable?

Chip

Hey all,

I am helping a friend out with one of these projectors and I know little to nothing about it. I'm technically savvy which is why I am working on it and hot him. I hooked it up to my laptop and was able to get an image from it but found that while the green channel looks great, the other two channels have small horizontal lines spread sporadically through them. Is this something that can be calibrated out or am I in trouble?

Thanks for the help.

Joe

Fitted a graphics card to my PC which has an adjustable gamma curve - made a huge difference - really chuffed! :-)

Thanks for all your help and suggestions.

Joe - doesn't sound too healthy, but, manuals for this projector can be downloaded from the very informative www.curtpalme.com. Someone had been 'tinkering' with the one I have and although it seemed unsalvagable, following the set up procedures in the user manual and service seminar soon got it back to life.

Hope that might help you.

Regards

Ian