View Full Version : Raising max contrast


lnx64
05-24-2012, 05:31 PM
How do you raise the maximum contrast, if the chassis doesn't have a subcontrast POT?

Since lowering the G2 voltage to prevent the red flickering on the dark screen (as lowering the BIAS or drive didn't do anything), while my maximum brightness is still very bright, my contrast has to be turned all the way up for a normal picture.

PS: The drive controls only have two POTs, red and blue, no green pot.

Username1
05-24-2012, 05:53 PM
you have a problem. the tube should go all the way down to dark, cutoff. And there are usually only 2 "drive" adjustments. Something is wrong check voltages around the tube socket. Something is not right if you have too much brightness....

lnx64
05-24-2012, 06:20 PM
No no, I was just saying that i CAN have a lot of brightness if cranked and little if turned down.. Brightness works fine.. Contrast on the other hand, goes down all the way, but for one quarter of a turn up, it does nothing, then when all the way up, it looks normal, but not high enough..

radiotvnut
05-24-2012, 06:45 PM
That may be as good as it gets. As the CRT's and other components in these sets age, it often becomes necessary to have the contrast control at maximum for the best picture.

lnx64
05-24-2012, 07:31 PM
Ok. I'll let it be.

I know I know, I find something new to talk about and be curious about. I just want the best out of a TV that is tired, but lucky it got me, and not someone who didn't trash it.

PS: There is no sams photofact for this TV.

rcaman
05-24-2012, 09:25 PM
did you put an asti flyback in this set or as we call them nasty asty terrible flybacks. steve

old_tv_nut
05-24-2012, 09:39 PM
I lost track - is this a solid-state set? if so, you are probably hitting a beam current limit designed to prevent excess X-rays. That doesn't mean it's working right, just that it's working. I think going further needs a service schematic with adjustment procedures.

lnx64
05-24-2012, 09:49 PM
It is solid state, 100%.

When the G2 was higher, the contrast did go much higher. Though blooming, it did give me "range".

It's the fact that it's seemingly lacking range right now that's a worry.

I can't find anything on this TV.

old_tv_nut
05-24-2012, 10:02 PM
It is solid state, 100%.

When the G2 was higher, the contrast did go much higher. Though blooming, it did give me "range".

It's the fact that it's seemingly lacking range right now that's a worry.

I can't find anything on this TV.

well, then it's worth seeing if you can find a compromise G2 setting

lnx64
05-24-2012, 10:45 PM
Yea, the G2 was lowered to just when the red flickering went away.. The G2 control was the ONLY thing that caused the red to stop flickering at total darkness.

I think this IS my compromise.

I won't feel bad, my Philips Magnavox TV from 1999, at max contrast looks exactly the same as this TV.

lnx64
05-25-2012, 01:31 AM
Oh god I feel like an idiot.

This whole time I'm going through my VCR. I bypass it, and it's nice and bright!!

The VCR thinks this TV is another VCR and is kicking in the macrovision, and causing the picture to darken, and brighten, darken and brighten. I was using the VCR as an AV switch and was getting the same results.


http://www.youtube.com/watch?v=xBg95pphFBY

Electronic M
05-25-2012, 12:55 PM
Be glad you don't have a roundy or any other tube era sets because the macrovision bars often light up the screen on retrace and appear as horizontal dashed lines right in the CENTER of the picture. It is annoying enough that I keep a macrovision remover on hand for when I watch pre-recorded VHS tapes.

lnx64
05-25-2012, 11:19 PM
Oh, you mean like this?! lol

http://img.photobucket.com/albums/v395/Evilweredragon/_IGP6888.jpg

This TV shows those things too, but as a glowing grey orb in the center, that only shows on dark screens.

Electronic M
06-01-2012, 05:14 PM
Actually more like this..... http://antiqueradio.org/art/MacrovisionInterference.jpg

lnx64
06-01-2012, 05:37 PM
Oh my god that's terrible! Oh by the way, your DVD players osd and front panel vfd looks exactly like my old mintek 2100.